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Fluid, Electrolyte, and Acid–Base Balance LEARNING OUTCOMES After completing this chapter, you will be able to: 1. Discuss the function, distribution, movement, and regulation of fluids and electrolytes in the body. 2. Describe the regulation of acid–base balance in the body, including the roles of the lungs, the kidneys and buffers. 3. Identify factors affecting normal body fluid, electrolyte, and acid–base balance. 4. Discuss the risk factors for and the causes and effects of fluid, electrolyte, and acid–base imbalances. 5. Collect assessment data related to the client’s fluid, electrolyte, and acid–base balances. 6. Identify examples of nursing diagnoses, outcomes, and interventions for clients with altered fluid, electrolyte, or acid–base balance. 7. Teach clients measures to maintain fluid and electrolyte balance. 8. Implement measures to correct imbalances of fluids and electrolytes or acids and bases such as enteral or parenteral replacements and blood transfusions. 9. Evaluate the effect of nursing and collaborative interventions on the client’s fluid, electrolyte, or acid–base balance.

CHAPTER

52

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KEY TERMS acid, 1432 acidosis, 1433 active transport, 1428 agglutinins, 1472 agglutinogens, 1472 alkalosis, 1433 anions, 1425 antibodies, 1472 antigens, 1472 arterial blood gases (ABGs), 1449 bases, 1432 buffers, 1433 cations, 1425 central venous catheters, 1456 colloid osmotic pressure, 1427 colloids, 1426 compensation, 1442 crystalloids, 1426 dehydration, 1437 diffusion, 1427 drip factor, 1465 electrolytes, 1425 extracellular fluid (ECF), 1424 filtration, 1427 filtration pressure, 1427 fluid volume deficit (FVD), 1435 fluid volume excess (FVE), 1435

hematocrit, 1449 hemolytic transfusion reaction, 1473 homeostasis, 1424 hydrostatic pressure, 1427 hypercalcemia, 1441 hyperchloremia, 1442 hyperkalemia, 1438 hypermagnesemia, 1442 hypernatremia, 1438 hyperphosphatemia, 1442 hypertonic, 1427 hypervolemia, 1435 hypocalcemia, 1441 hypochloremia, 1442 hypokalemia, 1438 hypomagnesemia, 1442 hyponatremia, 1438 hypophosphatemia, 1442 hypotonic, 1427 hypovolemia, 1435 insensible fluid loss, 1428 interstitial fluid, 1425 intracellular fluid (ICF), 1424 intravascular fluid, 1424 ions, 1425

In good health, a delicate balance of fluids, electrolytes, and acids and bases is maintained in the body. This balance, or physiologic homeostasis, depends on multiple physiologic processes that regulate fluid intake and output and the movement of water and the substances dissolved in it between the body compartments. Almost every illness has the potential to threaten this balance. Even in daily living, excessive temperatures or vigorous activity can disturb the balance if adequate water and salt intake is not maintained. Therapeutic measures, such as the use of diuretics or nasogastric suction, can also disturb the body’s homeostasis unless water and electrolytes are replaced.

BODY FLUIDS AND ELECTROLYTES The proportion of the human body composed of fluid is surprisingly large. Approximately 60% of the average healthy adult’s weight is water, the primary body fluid. In good health this volume remains relatively constant and the person’s weight varies by less than 0.2 kg (0.5 lb) in 24 hours, regardless of the amount of fluid ingested. Water is vital to health and normal cellular function, serving as ■ ■

1424

A medium for metabolic reactions within cells. A transporter for nutrients, waste products, and other substances.

■ ■ ■

isotonic, 1427 metabolic acidosis, 1442 metabolic alkalosis, 1442 milliequivalent, 1425 obligatory losses, 1429 oncotic pressure, 1427 osmolality, 1427 osmosis, 1426 osmotic pressure, 1427 overhydration, 1437 peripherally inserted central venous catheter (PICC), 1456 pH, 1432 pitting edema, 1436 plasma, 1424 renin-angiotensin-aldosterone system, 1429 respiratory acidosis, 1442 respiratory alkalosis, 1442 selectively permeable, 1426 solutes, 1426 solvent, 1426 specific gravity, 1449 third space syndrome, 1435 transcellular fluid, 1425 volume expanders, 1456

A lubricant. An insulator and shock absorber. One means of regulating and maintaining body temperature.

Age, sex, and body fat affect total body water. Infants have the highest proportion of water, accounting for 70% to 80% of their body weight. The proportion of body water decreases with aging. In people older than 60 years of age, it represents only about 50% of the total body weight. Women also have a lower percentage of body water than men. Women and the elderly have reduced body water due to decreased muscle mass and a greater percentage of fat tissue. Fat tissue is essentially free of water, whereas lean tissue contains a significant amount of water. Water makes up a greater percentage of a lean person’s body weight than an obese person’s.

Distribution of Body Fluids The body’s fluid is divided into two major compartments, intracellular and extracellular. Intracellular fluid (ICF) is found within the cells of the body. It constitutes approximately two-thirds of the total body fluid in adults. Extracellular fluid (ECF) is found outside the cells and accounts for about one-third of total body fluid. It is subdivided into compartments. The two main compartments of ECF are intravascular and interstitial. Intravascular fluid, or plasma, accounts for approximately 20% of the ECF

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Cell fluid 25 liters Total body fluid 40 liters

Plasma 3 liters

Interstitial and transcellular fluid 12 liters

Extracellular fluid 15 liters

Figure 52-1 ■ Total body fluid represents 40 L in an adult male weighing 70 kg (154 lb).

and is found within the vascular system. Interstitial fluid, accounting for approximately 75% of the ECF, surrounds the cells. The other compartments of ECF are the lymph and transcellular fluids. Examples of transcellular fluid include cerebrospinal, pericardial, pancreatic, pleural, intraocular, biliary, peritoneal, and synovial fluids (Figure 52-1 ■). Intracellular fluid is vital to normal cell functioning. It contains solutes such as oxygen, electrolytes, and glucose, and it provides a medium in which metabolic processes of the cell take place. Although extracellular fluid is in the smaller of the two compartments, it is the transport system that carries nutrients to and waste products from the cells. For example, plasma carries oxygen from the lungs and glucose from the gastrointestinal tract to the capillaries of the vascular system. From there, the oxygen and glucose move across the capillary membranes into the interstitial spaces and then across the cellular membranes into the cells. The opposite route is taken for waste products, such as carbon dioxide going from the cells to the lungs and metabolic acid wastes going eventually to the kidneys. Interstitial fluid transports wastes from the cells by way of the lymph system as well as directly into the blood plasma through capillaries.

Composition of Body Fluids Extracellular and intracellular fluids contain oxygen from the lungs, dissolved nutrients from the gastrointestinal tract, excretory products of metabolism such as carbon dioxide, and charged particles called ions.

Many salts dissociate in water, that is, break up into electrically charged ions. The salt sodium chloride breaks up into one ion of sodium (Na⫹) and one ion of chloride (Cl⫺). These charged particles are called electrolytes because they are capable of conducting electricity. The number of ions that carry a positive charge, called cations, and ions that carry a negative charge, called anions, should be equal. Examples of cations are sodium (Na⫹), potassium (K⫹), calcium (Ca2⫹), and magnesium (Mg2⫹). Examples of anions include chloride (Cl⫺), bicarbonate HCO3⫺, phosphate HPO42⫺, and sulfate SO42⫺. Electrolytes generally are measured in milliequivalents per liter of water (mEq/L) or milligrams per 100 milliliters (mg/100 mL). The term milliequivalent refers to the chemical combining power of the ion, or the capacity of cations to combine with anions to form molecules. This combining activity is measured in relation to the combining activity of the hydrogen ion (H⫹). Thus, 1 mEq of any anion equals 1 mEq of any cation. For example, sodium and chloride ions are equivalent, since they combine equally: 1 mEq of Na⫹ equals 1 mEq of Cl⫺. However, these cations and anions are not equal in weight: 1 mg of Na⫹ does not equal 1 mg of Cl⫺; rather, 3 mg of Na⫹ equals 2 mg of Cl⫺ . Clinically, the milliequivalent system is most often used. However, nurses need to be aware that different systems of measurement may be found when interpreting laboratory results. For example, calcium levels frequently are reported in milligrams per deciliter (1 dL ⫽ 100 mL) instead of milliequivalents per liter. It also is important to remember that laboratory tests are usually performed using blood plasma, an extracellular fluid. These results may reflect what is happening in the ECF, but it generally is not possible to directly measure electrolyte concentrations within the cell. The composition of fluids varies from one body compartment to another. In extracellular fluid, the principal electrolytes are sodium, chloride, and bicarbonate. Other electrolytes such as potassium, calcium, and magnesium are also present but in much smaller quantities. Plasma and interstitial fluid, the two primary components of ECF, contain essentially the same electrolytes and solutes, with the exception of protein. Plasma is a protein-rich fluid, containing large amounts of albumin, but interstitial fluid contains little or no protein. The composition of intracellular fluid differs significantly from that of ECF. Potassium and magnesium are the primary cations present in ICF, with phosphate and sulfate the major anions. As in ECF, other electrolytes are present within the cell, but in much smaller concentrations (Figure 52-2 ■). Maintaining a balance of fluid volumes and electrolyte compositions in the fluid compartments of the body is essential to health. Normal and unusual fluid and electrolyte losses must be replaced if homeostasis is to be maintained. Other body fluids such as gastric and intestinal secretions also contain electrolytes. This is of particular concern when these fluids are lost from the body (for example, in severe vomiting or diarrhea or when gastric suction removes the gastric secretions). Fluid and electrolyte imbalances can result from excessive losses through these routes.

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1426 UNIT X / Promoting Physiologic Health CATIONS

200

ANIONS

200 Na+

HCO3– Cl–

Milliequivalents per Liter (mEq/L)

150

150 HCO3– HCO3– HPO42– K+

100

100 Cl–

Na+ Na+

SO42–

Cl–

50

50 HPO42– Proteins

Org. acid K+ Ca2+ 0

Plasma

HPO42– SO42–

Mg2+ Proteins

K+ Interstitial fluid

Intracellular fluid

0

Plasma

Intracellular fluid

Interstitial fluid

Figure 52-2 ■ Electrolyte composition (cations and anions) of body fluid compartments. Martini, Fredric H.; Halyard, Rebecca A., Fundamentals of Anatomy and Physiology Interactive, (Media Edition), 4th ed., © 1998. Reproduced with permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

Movement of Body Fluids and Electrolytes The body fluid compartments are separated from one another by cell membranes and the capillary membrane. While these membranes are completely permeable to water, they are considered to be selectively permeable to solutes as substances move across them with varying degrees of ease. Small particles such as ions, oxygen, and carbon dioxide easily move across these membranes, but larger molecules like glucose and proteins have more difficulty moving between fluid compartments. The methods by which electrolytes and other solutes move are osmosis, diffusion, filtration, and active transport.

In the body, water is the solvent; the solutes include electrolytes, oxygen and carbon dioxide, glucose, urea, amino acids, and proteins. Osmosis occurs when the concentration of solutes on one side of a selectively permeable membrane, such as the capillary membrane, is higher than on the other side. For example, a marathon runner loses a significant amount of water through perspiration, increasing the concentration of solutes in the plasma because of water loss. This higher solute concentration draws water from the interstitial space and cells into the vascular compartment to equalize the concentration of solutes

Higher concentration

Osmosis

Lower concentration H20

Osmosis is the movement of water across cell membranes,

from the less concentrated solution to the more concentrated solution (Figure 52-3 ■). In other words, water moves toward the higher concentration of solute in an attempt to equalize the concentrations. Solutes are substances dissolved in a liquid. For example, when sugar is added to coffee, the sugar is the solute. Solutes may be crystalloids (salts that dissolve readily into true solutions) or colloids (substances such as large protein molecules that do not readily dissolve into true solutions). A solvent is the component of a solution that can dissolve a solute. In the previous example, coffee is the solvent for the sugar.

H20 H20

Dissolved substances

Semipermeable membrane

Water molecules

Figure 52-3 ■ Osmosis: Water molecules move from the less concentrated area to the more concentrated area in an attempt to equalize the concentration of solutions on two sides of a membrane.

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Diffusion is the continual intermingling of molecules in liquids, gases, or solids brought about by the random movement of the molecules. For example, two gases become mixed by the constant motion of their molecules. The process of diffusion occurs even when two substances are separated by a thin membrane. In the body, diffusion of water, electrolytes, and other substances occurs through the “split pores” of capillary membranes. The rate of diffusion of substances varies according to (a) the size of the molecules, (b) the concentration of the solution, and (c) the temperature of the solution. Larger molecules move less

Dissolved substance

Lower concentration

Semipermeable membrane

Figure 52-4 ■ Diffusion: The movement of molecules through a semipermeable membrane from an area of higher concentration to an area of lower concentration.

quickly than smaller ones because they require more energy to move about. With diffusion, the molecules move from a solution of higher concentration to a solution of lower concentration (Figure 52-4 ■). Increases in temperature increase the rate of motion of molecules and therefore the rate of diffusion.

Filtration Filtration is a process whereby fluid and solutes move together across a membrane from one compartment to another. The movement is from an area of higher pressure to one of lower pressure. An example of filtration is the movement of fluid and nutrients from the capillaries of the arterioles to the interstitial fluid around the cells. The pressure in the compartment that results in the movement of the fluid and substances dissolved in fluid out of the compartment is called filtration pressure. Hydrostatic pressure is the pressure exerted by a fluid within a closed system on the walls of a container in which it is contained. The hydrostatic pressure of blood is the force exerted by blood against the vascular walls (e.g., the artery walls). The principle involved in hydrostatic pressure is that fluids move from the area of greater pressure to the area of lesser pressure. Using the example of the blood vessels, the plasma proteins in the blood exert a colloid osmotic or oncotic pressure (see the earlier section “Osmosis”) that opposes the hydrostatic pressure and holds the fluid in the vascular compartment to maintain the vascular volume. When the hydrostatic pressure is greater than the osmotic pressure, the fluid filters out of the blood vessels. The filtration pressure in this example is the difference between the hydrostatic pressure and the osmotic pressure (Figure 52-5 ■).

Capillary bed Arterial side of capillary bed Hydrostatic pressure (arterial blood pressure)

Direction of filtration fluid and solutes

Venous side of capillary bed Colloid osmotic pressure Hydrostatic pressure (constant throughout (venous blood pressure) capillary bed)

Interstitial space

Direction of filtration fluid and solutes

Figure 52-5 ■ Schematic of filtration pressure changes within a capillary bed. On the arterial side, arterial blood pressure exceeds colloid osmotic pressure, so that water and dissolved substances move out of the capillary into the interstitial space. On the venous side, venous blood pressure is less than colloid osmotic pressure, so that water and dissolved substances move into the capillary.

Membrane Transport Animation

Diffusion

Higher concentration

MediaLink

in all fluid compartments. Osmosis is an important mechanism for maintaining homeostasis and fluid balance. The concentration of solutes in body fluids is usually expressed as the osmolality. Osmolality is determined by the total solute concentration within a fluid compartment and is measured as parts of solute per kilogram of water. Osmolality is reported as milliosmols per kilogram (mOsm/ kg). Sodium is by far the greatest determinant of serum osmolality, with glucose and urea also contributing. Potassium, glucose, and urea are the primary contributors to the osmolality of intracellular fluid. The term tonicity may be used to refer to the osmolality of a solution. Solutions may be termed isotonic, hypertonic, or hypotonic. An isotonic solution has the same osmolality as body fluids. Normal saline, 0.9% sodium chloride, is an isotonic solution. Hypertonic solutions have a higher osmolality than body fluids; 3% sodium chloride is a hypertonic solution. Hypotonic solutions such as one-half normal saline (0.45% sodium chloride), by contrast, have a lower osmolality than body fluids. Osmotic pressure is the power of a solution to draw water across a semipermeable membrane. When two solutions of different solute concentrations are separated by a semipermeable membrane, the solution of higher solute concentration exerts a higher osmotic pressure, drawing water across the membrane to equalize the concentrations of the solutions. For example, infusing a hypertonic intravenous solution such as 3% sodium chloride will draw fluid out of red blood cells (RBCs), causing them to shrink. On the other hand, a hypotonic solution administered intravenously will cause the RBCs to swell as water is drawn into the cells by their higher osmotic pressure. In the body, plasma proteins exert an osmotic draw called colloid osmotic pressure or oncotic pressure, pulling water from the interstitial space into the vascular compartment. This is an important mechanism in maintaining vascular volume.

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Filtration Pressure Animation

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Active Transport Substances can move across cell membranes from a less concentrated solution to a more concentrated one by active transport (Figure 52-6 ■). This process differs from diffusion and osmosis in that metabolic energy is expended. In active transport, a substance combines with a carrier on the outside surface of the cell membrane, and they move to the inside surface of the cell membrane. Once inside, they separate, and the substance is released to the inside of the cell. A specific carrier is required for each substance, enzymes are required for active transport, and energy is expended. This process is of particular importance in maintaining the differences in sodium and potassium ion concentrations of ECF and ICF. Under normal conditions, sodium concentrations are higher in the extracellular fluid, and potassium concentrations are higher inside the cells. To maintain these proportions, the active transport mechanism (the sodiumpotassium pump) is activated, moving sodium from the cells and potassium into the cells.

Regulating Body Fluids In a healthy person, the volumes and chemical composition of the fluid compartments stay within narrow safe limits. Normally fluid intake and fluid loss are balanced. Illness can upset this balance so that the body has too little or too much fluid.

Fluid Intake During periods of moderate activity at moderate temperature, the average adult drinks about 1,500 mL per day but needs 2,500 mL per day, an additional 1,000 mL. This added volume is acquired from foods and from the oxidation of these foods during metabolic processes. Interestingly, the water content of food is relatively large, contributing about 750 mL per day. The water content of fresh vegetables is approximately 90%, of fresh fruits about 85%, and of lean meats around 60%.

Intracellular fluid Na+ ATP

Na+ Na+ Na+ K+

K+ K+

ATP

K+

Na+

ATP K+

K+

ATP K+

Na+

Na+ Na+

K+ K+

K+

K+

Na+ Na+

Na+

Na+

Na+

Na+

Na+ Na+

K+ K+

SOURCE Oral fluids Water in foods Water as by-product of food metabolism Total

AMOUNT (ML) 1,200 to 1,500 1,000 200 2,400 to 2,700

Water as a by-product of food metabolism accounts for most of the remaining fluid volume required. This quantity is approximately 200 mL per day for the average adult. See Table 52–1. The thirst mechanism is the primary regulator of fluid intake. The thirst center is located in the hypothalamus of the brain. A number of stimuli trigger this center, including the osmotic pressure of body fluids, vascular volume, and angiotensin (a hormone released in response to decreased blood flow to the kidneys). For example, a long-distance runner loses significant amounts of water through perspiration and rapid breathing during a race, increasing the concentration of solutes and the osmotic pressure of body fluids. This increased osmotic pressure stimulates the thirst center, causing the runner to experience the sensation of thirst and the desire to drink to replace lost fluids. Thirst is normally relieved immediately after drinking a small amount of fluid, even before it is absorbed from the gastrointestinal tract. However, this relief is only temporary, and the thirst returns in about 15 minutes. The thirst is again temporarily relieved after the ingested fluid distends the upper gastrointestinal tract. These mechanisms protect the individual from drinking too much, because it takes from 30 minutes to 1 hour for the fluid to be absorbed and distributed throughout the body. See Figure 52-7 ■.

Fluid Output Fluid losses from the body counterbalance the adult’s 2,500-mL average daily intake of fluid, as shown in Table 52–2. There are four routes of fluid output:

Extracellular fluid

Na+

Na+

TABLE 52–1 Average Daily Fluid Intake for an Adult

Na+ Na+

1. Urine 2. Insensible loss through the skin as perspiration and through the lungs as water vapor in the expired air 3. Noticeable loss through the skin 4. Loss through the intestines in feces URINE. Urine formed by the kidneys and excreted from the uri-

K+ K+

K+ Cell membrane

Figure 52-6 ■ An example of active transport. Energy (ATP) is used to move sodium molecules and potassium molecules across a semipermeable membrane against sodium’s and potassium’s concentration gradients (i.e., from areas of lesser concentration to areas of greater concentration).

nary bladder is the major avenue of fluid output. Normal urine output for an adult is 1,400 to 1,500 mL per 24 hours, or at least 0.5 mL per kilogram per hour. In healthy people, urine output may vary noticeably from day to day. Urine volume automatically increases as fluid intake increases. If fluid loss through perspiration is large, however, urine volume decreases to maintain fluid balance in the body. INSENSIBLE LOSSES. Insensible fluid loss occurs through the skin and lungs. It is called insensible because it is usually not noticeable and cannot be measured. Insensible fluid loss through

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Increased osmolality of extracellular fluid

and

Decreased saliva secretion

Dry mouth

Maintaining Homeostasis Sensation of thirst: person seeks a drink

Water absorbed from gastrointestinal tract

Increased volume of extracellular fluid

and

Decreased osmolality of extracellular fluid

Figure 52-7 ■ Factors stimulating water intake through the thirst mechanism. From Lemone, Priscilla; Burke, Karen M., Medical Surgical Nursing: Critical Thinking in Client Care, 3rd ed © 2004. Reproduced with permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

the skin occurs in two ways. Water is lost through diffusion and through perspiration (which is noticeable but not measurable). Water losses through diffusion are not noticeable but normally account for 300 to 400 mL per day. This loss can be significantly increased if the protective layer of the skin is lost as with burns or large abrasions. Perspiration varies depending on factors such as environmental temperature and metabolic activity. Fever and exercise increase metabolic activity and heat production, thereby increasing fluid losses through the skin. Another type of insensible loss is the water in exhaled air. In an adult, this is normally 300 to 400 mL per day. When respiratory rate accelerates, for example, due to exercise or an elevated body temperature, this loss can increase.

TABLE 52–2 Average Daily Fluid Output for an Adult ROUTE Urine Insensible losses Lungs Skin Sweat Feces Total

AMOUNT (ML) 1,400 to 1,500 350 to 400 350 to 400 100 100 to 200 2,300 to 2,600

The volume and composition of body fluids is regulated through several homeostatic mechanisms. A number of body systems contribute to this regulation, including the kidneys, the endocrine system, the cardiovascular system, the lungs, and the gastrointestinal system. Hormones such as antidiuretic hormone (ADH; also known as arginine vasopressin or AVP), the renin-angiotensinaldosterone system, and atrial natriuretic factor are involved, as are mechanisms to monitor and maintain vascular volume. KIDNEYS. The kidneys are the primary regulator of body fluids and electrolyte balance. They regulate the volume and osmolality of extracellular fluids by regulating water and electrolyte excretion. The kidneys adjust the reabsorption of water from plasma filtrate and ultimately the amount excreted as urine. Although 135 to 180 L of plasma per day is normally filtered in an adult, only about 1.5 L of urine is excreted. Electrolyte balance is maintained by selective retention and excretion by the kidneys. The kidneys also play a significant role in acid–base regulation, excreting hydrogen ion (H⫹) and retaining bicarbonate. ANTIDIURETIC HORMONE. Antidiuretic hormone, which regulates water excretion from the kidney, is synthesized in the anterior portion of the hypothalamus and acts on the collecting ducts of the nephrons. When serum osmolality rises, ADH is produced, causing the collecting ducts to become more permeable to water. This increased permeability allows more water to be reabsorbed into the blood. As more water is reabsorbed, urine output falls and serum osmolality decreases because the water dilutes body fluids. Conversely, if serum osmolality decreases, ADH is suppressed, the collecting ducts become less permeable to water, and urine output increases. Excess water is excreted, and serum osmolality returns to normal. Other factors also affect the production and release of ADH, including blood volume, temperature, pain, stress, and some drugs such as opiates, barbiturates, and nicotine. See Figure 52-8 ■. RENIN-ANGIOTENSIN-ALDOSTERONE SYSTEM.

Specialized receptors in the juxtaglomerular cells of the kidney nephrons respond to changes in renal perfusion. This initiates the reninangiotensin-aldosterone system. If blood flow or pressure to the kidney decreases, renin is released. Renin causes the conversion of angiotensinogen to angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme. Angiotensin II

Fluid Balance Animation

Stimulates osmoreceptors in hypothalamic thirst center

The chyme that passes from the small intestine into the large intestine contains water and electrolytes. The volume of chyme entering the large intestine in an adult is normally about 1,500 mL per day. Of this amount, all but about 100 mL is reabsorbed in the proximal half of the large intestine. Certain fluid losses are required to maintain normal body function. These are known as obligatory losses. Approximately 500 mL of fluid must be excreted through the kidneys of an adult each day to eliminate metabolic waste products from the body. Water lost through respirations, through the skin, and in feces also are obligatory losses, necessary for temperature regulation and elimination of waste products. The total of all these losses is approximately 1,300 mL per day.

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FECES. Decreased volume of extracellular fluid

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↑ blood osmolality

↓ blood osmolality

Osmoreceptors in hypothalamus stimulate posterior pituitary to secrete ADH

ADH is suppressed

ADH causes distal tubules to become less permeable to water

ADH increases distal tubule permeability

↑ Reabsorption of H2O into blood

↓ Reabsorption of H2O into blood

Urine output ↓ Serum/blood osmolality ↓ as the water dilutes body fluids

Urine output ↑ Serum osmolality returns to normal

Figure 52-8 ■ Antidiuretic hormone (ADH) regulates water excretion from the kidneys.

acts directly on the nephrons to promote sodium and water retention. In addition, it stimulates the release of aldosterone from the adrenal cortex. Aldosterone also promotes sodium retention in the distal nephron. The net effect of the renin-angiotensinaldosterone system is to restore blood volume (and renal perfusion) through sodium and water retention.

maintaining electrolyte balance. Although the concentration of specific electrolytes differs between fluid compartments, a balance of cations (positively charged ions) and anions (negatively charged ions) always exists. Electrolytes are important for ■ ■

ATRIAL NATRIURETIC FACTOR. Atrial natriuretic factor (ANF)

■

is released from cells in the atrium of the heart in response to excess blood volume and stretching of the atrial walls. Acting on the nephrons, ANF promotes sodium wasting and acts as a potent diuretic, thus reducing vascular volume. ANF also inhibits thirst, reducing fluid intake.

■

Regulating Electrolytes Electrolytes, charged ions capable of conducting electricity, are present in all body fluids and fluid compartments. Just as maintaining the fluid balance is vital to normal body function, so is

Maintaining fluid balance. Contributing to acid–base regulation. Facilitating enzyme reactions. Transmitting neuromuscular reactions.

Most electrolytes enter the body through dietary intake and are excreted in the urine. Some electrolytes, such as sodium and chloride, are not stored by the body and must be consumed daily to maintain normal levels. Potassium and calcium, on the other hand, are stored in the cells and bone, respectively. When serum levels drop, ions can shift out of the storage “pool” into the blood to maintain adequate serum levels for normal functioning. The regulatory mechanisms and functions of the major electrolytes are summarized in Table 52–3.

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TABLE 52–3

Regulation and Functions of Electrolytes

ELECTROLYTE Sodium (Na⫹)

Potassium (K⫹)

REGULATION ■ Renal reabsorption or excretion ⫹ ■ Aldosterone increases Na reabsorption in collecting duct of nephrons ■ Renal excretion and conservation ⫹ ■ Aldosterone increases K excretion ■ Movement into and out of cells ⫹ ■ Insulin helps move K into cells; tissue damage and acidosis shift K⫹ out of cells into ECF

Calcium (Ca2⫹)

■ ■

Magnesium (Mg2⫹)

■ ■

Chloride (Cl⫺)

Phosphate (PO4⫺)

Bicarbonate (HCO3⫺)

Redistribution between bones and ECF Parathyroid hormone and calcitriol increase serum Ca2⫹ levels; calcitonin decreases serum levels

Conservation and excretion by kidneys Intestinal absorption increased by vitamin D and parathyroid hormone

Excreted and reabsorbed along with sodium in the kidneys ■ Aldosterone increases chloride reabsorption with sodium ■ Excretion and reabsorption by the kidneys ■ Parathyroid hormone decreases serum levels by increasing renal excretion ■ Reciprocal relationship with calcium: increasing serum calcium levels decrease phosphate levels; decreasing serum calcium increases phosphate ■ Excretion and reabsorption by the kidneys ■ Regeneration by kidneys ■

FUNCTION ■ Regulating ECF volume and distribution ■ Maintaining blood volume ■ Transmitting nerve impulses and contracting muscles ■ Maintaining ICF osmolality ■ Transmitting nerve and other electrical impulses ■ Regulating cardiac impulse transmission and muscle contraction ■ Skeletal and smooth muscle function ■ Regulating acid–base balance ■ Forming bones and teeth ■ Transmitting nerve impulses ■ Regulating muscle contractions ■ Maintaining cardiac pacemaker (automaticity) ■ Blood clotting ■ Activating enzymes such as pancreatic lipase and phospholipase ■ Intracellular metabolism ■ Operating sodium-potassium pump ■ Relaxing muscle contractions ■ Transmitting nerve impulses ■ Regulating cardiac function ■ HCl production ■ Regulating ECF balance and vascular volume ■ Regulating acid–base balance ■ Buffer in oxygen–carbon dioxide exchange in RBCs ■ Forming bones and teeth ■ Metabolizing carbohydrate, protein, and fat ■ Cellular metabolism; producing ATP and DNA ■ Muscle, nerve, and RBC function ■ Regulating acid–base balance ■ Regulating calcium levels ■ Major body buffer involved in acid–base regulation

Sodium (Na⫹)

Calcium (Ca2⫹)

Sodium is the most abundant cation in extracellular fluid and a major contributor to serum osmolality. Normal serum sodium levels are 135 to 145 mEq/L. Sodium functions largely in controlling and regulating water balance. When sodium is reabsorbed from the kidney tubules, chloride and water are reabsorbed with it, thus maintaining ECF volume. Sodium is found in many foods, such as bacon, ham, processed cheese, and table salt.

The vast majority, 99%, of calcium in the body is in the skeletal system, with a relatively small amount in extracellular fluid. Although this calcium outside the bones and teeth amounts to only about 1% of the total calcium in the body, it is vital in regulating muscle contraction and relaxation, neuromuscular function, and cardiac function. ECF calcium is regulated by a complex interaction of parathyroid hormone, calcitonin, and calcitriol, a metabolite of vitamin D. When calcium levels in the

Potassium (K⫹) Potassium is the major cation in intracellular fluids, with only a small amount found in plasma and interstitial fluid. ICF levels of potassium are usually 125 to 140 mEq/L while normal serum potassium levels are 3.5 to 5.0 mEq/L. The ratio of intracellular to extracellular potassium must be maintained for neuromuscular response to stimuli. Potassium is a vital electrolyte for skeletal, cardiac, and smooth muscle activity. It is involved in maintaining acid–base balance as well, and it contributes to intracellular enzyme reactions. Potassium must be ingested daily because the body can’t conserve it. Many fruits and vegetables, meat, fish, and other foods contain potassium (see Box 52–1).

BOX 52–1

Potassium-Rich Foods

VEGETABLES Avocado Raw carrot Baked potato Raw tomato Spinach

FRUITS Dried fruits (e.g., raisins and dates) Banana Apricot Cantaloupe Orange

MEATS AND FISH Beef Cod Pork Veal

BEVERAGES Milk Orange juice Apricot nectar

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ECF fall, parathyroid hormone and calcitriol cause calcium to be released from bones into ECF and increase the absorption of calcium in the intestines, thus raising serum calcium levels. Conversely, calcitonin stimulates the deposition of calcium in bone, reducing the concentration of calcium ions in the blood. With aging, the intestines absorb calcium less effectively and more calcium is excreted via the kidneys. Calcium shifts out of the bone to replace these ECF losses, increasing the risk of osteoporosis and fractures of the wrists, vertebrae, and hips. Lack of weight-bearing exercise (which helps keep calcium in the bones) and a vitamin D deficiency because of inadequate exposure to sunlight contribute to this risk. Milk and milk products are the richest sources of calcium, with other foods such as dark green leafy vegetables and canned salmon containing smaller amounts. Many clients benefit from calcium supplements. Serum calcium levels are often reported in two ways, based upon the way it is circulating in the plasma. Approximately 50% of serum calcium circulates in a free, ionized, or unbound form. The other 50% circulates in the plasma bound to either plasma proteins or other nonprotein ions. The normal total serum calcium levels, which range from 8.5 to 10.5 mg/dL, represent both bound and unbound calcium. The normal ionized serum calcium, which ranges from 4.0 to 5.0 mg/dL, represents calcium circulating in the plasma in free, or unbound, form (Hayes, 2004).

Magnesium (Mg2⫹) Magnesium is primarily found in the skeleton and in intracellular fluid. It is the second most abundant intracellular cation with normal serum levels of 1.5 to 2.5 mEq/L. It is important for intracellular metabolism, being particularly involved in the production and use of ATP. Magnesium also is necessary for protein and DNA synthesis within the cells. Only about 1% of the body’s magnesium is in ECF; here it is involved in regulating neuromuscular and cardiac function. Maintaining and ensuring adequate magnesium levels is an important part of care of clients with cardiac disorders. Cereal grains, nuts, dried fruit, legumes, and green leafy vegetables are good sources of magnesium in the diet, as are dairy products, meat, and fish. ⫺

Chloride (Cl ) Chloride is the major anion of ECF, and normal serum levels are 95 to 108 mEq/L. Chloride functions with sodium to regulate serum osmolality and blood volume. The concentration of chloride in ECF is regulated secondarily to sodium; when sodium is reabsorbed in the kidney, chloride usually follows. Chloride is a major component of gastric juice as hydrochloric acid (HCl) and is involved in regulating acid–base balance. It also acts as a buffer in the exchange of oxygen and carbon dioxide in RBCs. Chloride is found in the same foods as sodium.

Phosphate PO4⫺ Phosphate is the major anion of intracellular fluids. It also is found in ECF, bone, skeletal muscle, and nerve tissue. Normal serum levels of phospate in adults range from 2.5 to 4.5 mg/dL. Children have much higher phosphate levels than adults, with

that of a newborn nearly twice that of an adult. Higher levels of growth hormone and a faster rate of skeletal growth probably account for this difference. Phosphate is involved in many chemical actions of the cell; it is essential for functioning of muscles, nerves, and red blood cells. It is also involved in the metabolism of protein, fat, and carbohydrate. Phosphate is absorbed from the intestine and is found in many foods such as meat, fish, poultry, milk products, and legumes.

Bicarbonate HCO3⫺ Bicarbonate is present in both intracellular and extracellular fluids. Its primary function is regulating acid–base balance as an essential component of the carbonic acid–bicarbonate buffering system. Extracellular bicarbonate levels are regulated by the kidneys: Bicarbonate is excreted when too much is present; if more is needed, the kidneys both regenerate and reabsorb bicarbonate ions. Unlike other electrolytes that must be consumed in the diet, adequate amounts of bicarbonate are produced through metabolic processes to meet the body’s needs.

ACID–BASE BALANCE An important part of regulating the chemical balance or homeostasis of body fluids is regulating their acidity or alkalinity. An acid is a substance that releases hydrogen ions (H⫹) in solution. Strong acids such as hydrochloric acid release all or nearly all their hydrogen ions; weak acids like carbonic acid release some hydrogen ions. Bases or alkalis have a low hydrogen ion concentration and can accept hydrogen ions in solution. The relative acidity or alkalinity of a solution is measured as pH. The pH reflects the hydrogen ion concentration of the solution: The higher the hydrogen ion concentration (and the more acidic the solution), the lower the pH. Water has a pH of 7 and is neutral; that is, it is neither acidic in nature nor is it alkaline. Solutions with a pH lower than 7 are acidic; those with a pH higher than 7 are alkaline. The pH scale is logarithmic: A solution with a pH of 5 is 10 times more acidic than one with a pH of 6.

Regulation of Acid–Base Balance Body fluids are maintained within a narrow range that is slightly alkaline. The normal pH of arterial blood is between 7.35 and 7.45 (Figure 52-9 ■). Acids are continually produced during mepH 6.8

Death

7.35

Acidosis

7.45

Normal

7.8

Alkalosis

Death

pH scale 1 Acidic solution (high H+)

7 Neutral

14 Alkaline solution (low H+)

Figure 52-9 ■ Body fluids are normally slightly alkaline, between a pH of 7.35 and 7.45.

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Buffers prevent excessive changes in pH by removing or releas-

ing hydrogen ions. If excess hydrogen ion is present in body fluids, buffers bind with the hydrogen ion, minimizing the change in pH. When body fluids become too alkaline, buffers can release hydrogen ion, again minimizing the change in pH. The action of a buffer is immediate, but limited in its capacity to maintain or restore normal acid–base balance. The major buffer system in extracellular fluids is the bicarbonate (HCO3⫺) and carbonic acid (H2CO3) system. When a strong acid such as hydrochloric acid (HCl) is added, it combines with bicarbonate and the pH drops only slightly. A strong base such as sodium hydroxide combines with carbonic acid, the weak acid of the buffer pair, and the pH remains within the narrow range of normal. The amounts of bicarbonate and carbonic acid in the body vary; however, as long as a ratio of 20 parts of bicarbonate to 1 part of carbonic acid is maintained, the pH remains within its normal range of 7.35 to 7.45 (Figure 52-10 ■). Adding a strong acid to ECF can change this ratio as bicarbonate is depleted in neutralizing the acid. When this happens, the pH drops, and the client has a condition called acidosis. The ratio can also be upset by adding a strong base to ECF, depleting carbonic acid as it combines with the base. In this case the pH rises and the client has alkalosis. In addition to the bicarbonate–carbonic acid buffer system, plasma proteins, hemoglobin, and phosphates also function as buffers in body fluids.

Respiratory Regulation The lungs help regulate acid–base balance by eliminating or retaining carbon dioxide (CO2), a potential acid. Combined with water, carbon dioxide forms carbonic acid (CO2 ⫹ H2O → H2CO3). This chemical reaction is reversible; carbonic acid

1 part carbonic acid or 1.2 mEq/L

Death 6.8

20 parts bicarbonate or 24 mEq/L

Acidosis

Normal 7.35

Alkalosis 7.45

7.8

Figure 52-10 ■ Carbonic acid–bicarbonate ratio and pH.

Death

Renal Regulation Although buffers and the respiratory system can compensate for changes in pH, the kidneys are the ultimate long-term regulator of acid–base balance. They are slower to respond to changes, requiring hours to days to correct imbalances, but their response is more permanent and selective than that of the other systems (Yucha, 2004). The kidneys maintain acid–base balance by selectively excreting or conserving bicarbonate and hydrogen ions. When excess hydrogen ion is present and the pH falls (acidosis), the kidneys reabsorb and regenerate bicarbonate and excrete hydrogen ion. In the case of alkalosis and a high pH, excess bicarbonate is excreted and hydrogen ion is retained. The normal serum bicarbonate level is 22 to 26 mEq/L. The relationship of the respiratory and renal regulation of acid–base balance is further explained in Box 52–2.

BOX 52–2 Physiological Regulation of Acid–Base Balance Lungs CO2 ⫹ H2O Carbon dioxide ⫹ water

↔

H2CO3 Carbonic acid

↔

Kidneys H ⫹ HCO3 Hydrogen ⫹ bicarbonate

The lungs and kidneys are the two major systems that are working on a continuous basis to help regulate the acid–base balance in the body. In the biochemical reactions above, the processes are all reversible and go back and forth as the body’s needs change. The lungs can work very quickly and do their part by either retaining or getting rid of carbon dioxide by changing the rate and depth of respirations. The kidneys work much more slowly; they may take hours to days to regulate the balance by either excreting or conserving hydrogen and bicarbonate ions. Under normal conditions, the two systems work together to maintain homeostasis.

Acid-Base Balance Animation

Buffers

breaks down into carbon dioxide and water. Working together with the bicarbonate–carbonic acid buffer system, the lungs regulate acid–base balance and pH by altering the rate and depth of respirations. The response of the respiratory system to changes in pH is rapid, occurring within minutes. Carbon dioxide is a powerful stimulator of the respiratory center. When blood levels of carbonic acid and carbon dioxide rise, the respiratory center is stimulated and the rate and depth of respirations increase. Carbon dioxide is exhaled, and carbonic acid levels fall. By contrast, when bicarbonate levels are excessive, the rate and depth of respirations are reduced. This causes carbon dioxide to be retained, carbonic acid levels to rise, and the excess bicarbonate to be neutralized. Carbon dioxide levels in the blood are measured as the PCO2, or partial pressure of the dissolved gas in the blood. PCO2 refers to the pressure of carbon dioxide in venous blood. PaCO2 refers to the pressure of carbon dioxide in arterial blood. The normal PaCO2 is 35 to 45 mm Hg.

MediaLink

tabolism. Several body systems, including buffers, the respiratory system, and the renal system, are actively involved in maintaining the narrow pH range necessary for optimal function. Buffers help maintain acid–base balance by neutralizing excess acids or bases. The lungs and the kidneys help maintain a normal pH by either excreting or retaining acids and bases.

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FACTORS AFFECTING BODY FLUID, ELECTROLYTES, AND ACID–BASE BALANCE The ability of the body to adjust fluids, electrolytes, and acid–base balance is influenced by age, gender and body size, environmental temperature, and lifestyle.

Age Infants and growing children have much greater fluid turnover than adults because their higher metabolic rate increases fluid loss. Infants lose more fluid through the kidneys because immature kidneys are less able to conserve water than adult kidneys. In addition, infants’ respirations are more rapid and the body surface area is proportionately greater than that of adults, increasing insensible fluid losses. The more rapid turnover of fluid plus the losses produced by disease can create critical fluid imbalances in children much more rapidly than in adults. In elderly people, the normal aging process may affect fluid balance. The thirst response often is blunted. Antidiuretic hormone levels remain normal or may even be elevated, but the nephrons become less able to conserve water in response to ADH. Increased levels of atrial natriuretic factor seen in older adults may also contribute to this impaired ability to conserve water. These normal changes of aging increase the risk of dehydration. When combined with the increased likelihood of heart diseases, impaired renal function, and multiple drug regimens, the older adult’s risk for fluid and electrolyte imbalance is significant. Additionally, it is important to consider that the older

LIFESPAN CONSIDERATIONS

Infants are at high risk for fluid and electrolyte imbalance because Their immature kidneys cannot concentrate urine. They have a rapid respiratory rate and proportionately larger body surface area than adults, leading to greater insensate loss through the skin and respirations. ■ They cannot express thirst, nor actively seek fluids. ■ ■

Vomiting and/or diarrhea in infants and young children can lead quickly to electrolyte imbalance. Oral rehydration therapy (ORT) (e.g., electrolyte solutions such as Pedialyte) should be used to restore fluid and electrolyte balance in mild to moderate dehydration (American Medical Association et al., 2004). Prompt treatment with ORT can prevent the need for intravenous therapy and hospitalization (Spandorfer, Alessandrini, Joffe, Localio, & Shaw, 2005). Even if the child is nauseated and vomiting, small sips of ORT can be helpful. ELDERS Certain changes related to aging place the elder at risk for serious problems with fluid and electrolyte imbalance, if homeostatic mechanisms are compromised. Some of the changes are A decrease in thirst sensation. A decrease in ability of the kidneys to concentrate urine. ■ A decrease in intracellular fluid and in total body water. ■ A decrease in response to body hormones that help regulate fluid and electrolytes. ■

Gender and Body Size Total body water also is affected by gender and body size. Because fat cells contain little or no water, and lean tissue has a high water content, people with a higher percentage of body fat have less body fluid. Women have proportionately more body fat and less body water than men. Water accounts for approximately 60% of an adult man’s weight, but only 52% for an adult woman. In an obese individual this may be even less, with water responsible for only 30% to 40% of the person’s weight.

Environmental Temperature People with an illness and those participating in strenuous activity are at risk for fluid and electrolyte imbalances when the environmental temperature is high. Fluid losses through sweating are increased in hot environments as the body attempts to dissipate heat. These losses are even greater in people who have not been acclimatized to the environment. Both salt and water are lost through sweating. When only water is replaced, salt depletion is a risk. The person who is salt depleted may experience fatigue, weakness, headache, and gastrointestinal symptoms such as anorexia and nausea. The risk of adverse effects is even greater if lost water is not replaced. Body temperature rises, and the person is at risk for heat exhaustion or heatstroke. Heatstroke may occur in older adults or ill people during prolonged periods of heat; it can also affect athletes and

Fluid and Electrolyte Imbalance

INFANTS AND CHILDREN

■

adult has thinner, more fragile skin and veins, which can make an intravenous insertion more difficult.

Other factors that may influence fluid and electrolyte balance in elders are ■ ■

■ ■ ■

■

Increased use of diuretics for hypertension and heart disease. Decreased intake of food and water, especially in elders with dementia or who are dependent on others to feed them and offer them fluids. Preparations for certain diagnostic tests that have the client NPO for long periods of time or cause diarrhea from laxative preps. Clients with impaired renal function, such as elders with diabetes. Those having certain diagnostic procedures. (Dyes used for some procedures, such as arteriograms and cardiac catheterizations, may cause further renal problems. Always see that the client is well hydrated before, during, and after the procedure to help in diluting and excreting the dye. If the client is NPO for the procedure, the nurse should check with the primary care provider to see if IV fluids are needed.) Any condition that may tax the normal compensatory mechanisms, such as a fever, influenza, surgery, or heat exposure.

All of these conditions increase elders’ risk for fluid and electrolyte imbalance. The change can happen quickly and become serious in a short time. Astute observations and quick actions by the nurse can help prevent serious consequences. A change in mental status may be the first symptom of impairment and must be further evaluated to determine the cause.

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laborers when their heat production exceeds the body’s ability to dissipate heat. Consuming adequate amounts of cool liquids, particularly during strenuous activity, reduces the risk of adverse effects from heat. Balanced electrolyte solutions and carbohydrate-electrolyte solutions such as sports drinks are recommended because they replace both water and electrolytes lost through sweat.

Lifestyle

A number of factors such as illness, trauma, surgery, and medications can affect the body’s ability to maintain fluid, electrolyte, and acid–base balance. The kidneys play a major role in maintaining fluid, electrolyte, and acid–base balance, and renal disease is a significant cause of imbalance. Clients who are confused or unable to communicate their needs are at risk for inadequate fluid intake. Vomiting, diarrhea, or nasogastric suction can cause significant fluid losses. Tissue trauma, such as burns, causes fluid and electrolytes to be lost from damaged cells. Decreased blood flow to the kidneys due to impaired cardiac function stimulates the renin-angiotensin-aldosterone system, causing sodium and water retention. Medications such as diuretics or corticosteroids can result in abnormal losses of electrolytes and fluid loss or retention. Diseases such as diabetes mellitus or chronic obstructive lung disease may affect

Fluid imbalances are of two basic types: isotonic and osmolar. Isotonic imbalances occur when water and electrolytes are lost or gained in equal proportions, so that the osmolality of body fluids remains constant. Osmolar imbalances involve the loss or gain of only water, so that the osmolality of the serum is altered. Thus four categories of fluid imbalances may occur: (a) an isotonic loss of water and electrolytes, (b) an isotonic gain of water and electrolytes, (c) a hyperosmolar loss of only water, and (d) a hypo-osmolar gain of only water. These are referred to, respectively, as fluid volume deficit, fluid volume excess, dehydration (hyperosmolar imbalance), and overhydration (hypo-osmolar imbalance).

Fluid Volume Deficit Isotonic fluid volume deficit (FVD) occurs when the body loses both water and electrolytes from the ECF in similar proportions. Thus, the decreased volume of fluid remains isotonic. In FVD, fluid is initially lost from the intravascular compartment, so it often is called hypovolemia. FVD generally occurs as a result of (a) abnormal losses through the skin, gastrointestinal tract, or kidney; (b) decreased intake of fluid; (c) bleeding; or (d) movement of fluid into a third space. See the section on third space syndrome that follows. For the risk factors and clinical signs related to fluid volume deficit, see Table 52–4. THIRD SPACE SYNDROME. In third space syndrome, fluid shifts from the vascular space into an area where it is not readily accessible as extracellular fluid. This fluid remains in the body but is essentially unavailable for use, causing an isotonic fluid volume deficit. Fluid may be sequestered in the bowel, in the interstitial space as edema, in inflamed tissue, or in potential spaces such as the peritoneal or pleural cavities. The client with third space syndrome has an isotonic fluid deficit but may not manifest apparent fluid loss or weight loss. Careful nursing assessment is vital to effectively identify and intervene for clients experiencing third-spacing. Because the fluid shifts back into the vascular compartment after time, assessment for manifestations of fluid volume excess or hypervolemia is also vital.

Fluid Volume Excess Fluid volume excess (FVE) occurs when the body retains both

water and sodium in similar proportions to normal ECF. This is commonly referred to as hypervolemia (increased blood volume). FVE is always secondary to an increase in the total body sodium content, which leads to an increase in total body water. Because both water and sodium are retained, the serum sodium concentration remains essentially normal and the excess volume of fluid is isotonic. Specific causes of FVE include (a) excessive intake of sodium chloride; (b) administering sodium-containing infusions too rapidly, particularly to clients

Determining Body Fluid Problems Application

DISTURBANCES IN FLUID VOLUME, ELECTROLYTE, AND ACID–BASE BALANCES

Fluid Imbalances

MediaLink

Other factors such as diet, exercise, and stress affect fluid, electrolyte, and acid–base balance. The intake of fluids and electrolytes is affected by the diet. People with anorexia nervosa or bulimia are at risk for severe fluid and electrolyte imbalances because of inadequate intake or purging regimens (e.g., induced vomiting, use of diuretics and laxatives). Seriously malnourished people have decreased serum albumin levels, and may develop edema because the osmotic draw of fluid into the vascular compartment is reduced. When calorie intake is not adequate to meet the body’s needs, fat stores are broken down and fatty acids are released, increasing the risk of acidosis. Regular weight-bearing physical exercise such as walking, running, or bicycling has a beneficial effect on calcium balance. The rate of bone loss that occurs in postmenopausal women and older men is slowed with regular exercise, reducing the risk of osteoporosis. Stress can increase cellular metabolism, blood glucose concentration, and catecholamine levels. In addition, stress can increase production of ADH, which in turn decreases urine production. The overall response of the body to stress is to increase the blood volume. Other lifestyle factors can also affect fluid, electrolyte, and acid–base balance. Heavy alcohol consumption affects electrolyte balance, increasing the risk of low calcium, magnesium, and phosphate levels. The risk of acidosis associated with breakdown of fat tissue also is greater in the person who drinks large amounts of alcohol.

acid–base balance. Diabetic ketoacidosis, cancer, and head injury may also lead to electrolyte imbalances.

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TABLE 52–4

Isotonic Fluid Volume Deficit

RISK FACTORS Loss of water and electrolytes from ■ Vomiting ■ Diarrhea ■ Excessive sweating ■ Polyuria ■ Fever ■ Nasogastric suction ■ Abnormal drainage or wound losses Insufficient intake due to ■ Anorexia ■ Nausea ■ Inability to access fluids ■ Impaired swallowing ■ Confusion, depression

CLINICAL MANIFESTATIONS Complaints of weakness and thirst Weight loss ■ 2% loss ⫽ mild FVD ■ 5% loss ⫽ moderate ■ 8% loss ⫽ severe Fluid intake less than output Decreased tissue turgor Dry mucous membranes, sunken eyeballs, decreased tearing Subnormal temperature Weak, rapid pulse Decreased blood pressure Postural (orthostatic) hypotension (significant drop in BP when moving from lying to sitting or standing position) Flat neck veins; decreased capillary refill Decreased central venous pressure Decreased urine volume (1.030) Increased hematocrit Increased blood urea nitrogen (BUN)

with impaired regulatory mechanisms; and (c) disease processes that alter regulatory mechanisms, such as heart failure, renal failure, cirrhosis of the liver, and Cushing’s syndrome. The risk factors and clinical manifestations for FVE are summarized in Table 52–5. EDEMA. In fluid volume excess, both intravascular and interstitial spaces have an increased water and sodium content. Excess interstitial fluid is known as edema. Edema typically is most apparent in areas where the tissue pressure is low, such as around the eyes, and in dependent tissues (known as dependent edema), where hydrostatic capillary pressure is high. Edema can be caused by several different mechanisms. The three main mechanisms are increased capillary hydrostatic pressure, decreased plasma oncotic pressure, and increased capillary permeability. It may be due to FVE that increases capillary

TABLE 52–5

NURSING INTERVENTIONS Assess for clinical manifestations of FVD. Monitor weight and vital signs, including temperature. Assess tissue turgor. Monitor fluid intake and output. Monitor laboratory findings. Administer oral and intravenous fluids as indicated. Provide frequent mouth care. Implement measures to prevent skin breakdown. Provide for safety, e.g., provide assistance for a client rising from bed.

hydrostatic pressures, pushing fluid into the interstitial tissues. This type of edema is often seen in dependent tissues such as the feet, ankles, and sacrum because of the effects of gravity. Low levels of plasma proteins from malnutrition or liver or kidney diseases can reduce the plasma oncotic pressure so that fluid is not drawn into the capillaries from interstitial tissues, causing edema. With tissue trauma and some disorders such as allergic reactions, capillaries become more permeable, allowing fluid to escape into interstitial tissues. Obstructed lymph flow impairs the movement of fluid from interstitial tissues back into the vascular compartment, resulting in edema. Pitting edema is edema that leaves a small depression or pit after finger pressure is applied to the swollen area. The pit is caused by movement of fluid to adjacent tissue, away from the point of pressure (Figure 52-11 ■). Within 10 to 30 seconds the pit normally disappears.

Isotonic Fluid Volume Excess

RISK FACTORS Excess intake of sodium-containing intravenous fluids Excess ingestion of sodium in diet or medications (e.g., sodium bicarbonate antacids such as Alka-Seltzer or hypertonic enema solutions such as Fleet’s) Impaired fluid balance regulation related to ■ Heart failure ■ Renal failure ■ Cirrhosis of the liver

CLINICAL MANIFESTATIONS Weight gain ■ 2% gain ⫽ mild FVE ■ 5% gain ⫽ moderate ■ 8% gain ⫽ severe Fluid intake greater than output Full, bounding pulse; tachycardia Increased blood pressure and central venous pressure Distended neck and peripheral veins; slow vein emptying Moist crackles (rales) in lungs; dyspnea, shortness of breath Mental confusion

NURSING INTERVENTIONS Assess for clinical manifestations of FVE. Monitor weight and vital signs. Assess for edema. Assess breath sounds. Monitor fluid intake and output. Monitor laboratory findings. Place in Fowler’s position. Administer diuretics as ordered. Restrict fluid intake as indicated. Restrict dietary sodium as ordered. Implement measures to prevent skin breakdown.

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CHAPTER 52 / Fluid, Electrolyte, and Acid–Base Balance 1437 2mm

1+ Barely detectable 4mm

2+ 2 to 4 mm 6mm 3+ 5 to 7 mm

12mm 4+ More than 7 mm B

A

Figure 52-11 ■ Evaluation of edema. A, Palpate for edema over the tibia as shown here and behind the medial malleolus, and over the dorsum of each foot. B, Four-point scale for grading edema.

Dehydration

Overhydration

Dehydration, or hyperosmolar imbalance, occurs when water is

Overhydration, also known as hypo-osmolar imbalance or water excess, occurs when water is gained in excess of electrolytes, resulting in low serum osmolality and low serum sodium levels. Water is drawn into the cells, causing them to swell. In the brain this can lead to cerebral edema and impaired neurologic function. Water intoxication often occurs when both fluid and electrolytes are lost, for example, through excessive sweating, but only water is replaced. It can also result from the syndrome of inappropriate antidiuretic hormone (SIADH), a disorder that can occur with some malignant tumors, AIDS, head injury, or administration of certain drugs such as barbiturates or anesthetics.

lost from the body leaving the client with excess sodium. Because water is lost while electrolytes, particularly sodium, are retained, the serum osmolality and serum sodium levels increase. Water is drawn into the vascular compartment from the interstitial space and cells, resulting in cellular dehydration. Older adults are at particular risk for dehydration because of decreased thirst sensation. This type of water deficit also can affect clients who are hyperventilating or have prolonged fever or are in diabetic ketoacidosis and those receiving enteral feedings with insufficient water intake.

DRUG CAPSULE

Diuretic Agent

furosemide (Lasix)

THE CLIENT WITH FLUID VOLUME EXCESS

NURSING RESPONSIBILITIES ■

■

■

CLIENT AND FAMILY TEACHING ■

■ ■

■

■

Medication should be taken exactly as directed. If you miss a dose, take it as soon as possible; however, if a day has been missed, do not double the dose the next day. Weigh on a daily basis and report weight gain or loss of more than 3 lb in 1 day to your primary care provider. Contact your primary care provider immediately if you begin to experience muscle weakness, cramps, nausea, dizziness, numbness, or tingling of the extremities. Some form of potassium supplementation will be needed. The primary care provider may order oral potassium supplements for you; if not, you will need to consume a diet high in potassium. Make position changes slowly in order to minimize dizziness from orthostatic hypotension.

Note: Prior to administering any medication, review all aspects with a current drug handbook or other reliable source.

Furosemide Drug Animation

■

Assess the client’s fluid status regularly. Assessment should include daily weights, close monitoring of intake and output, skin turgor, edema, lung sounds, and mucous membranes. Monitor the client’s potassium levels. Furosemide is a loop diuretic which excretes potassium and may result in hypokalemia. Administer in the morning to avoid increased urination during hours of sleep. If the client is also taking digitalis glycosides, he or she should be assessed for anorexia, nausea, vomiting, muscle cramps, paresthesia, and confusion. The potassium-depleting effect of furosemide places the client at increased risk for digitalis toxicity.

MediaLink

Furosemide inhibits sodium and chloride reabsorption in the loop of Henle and the distal renal tubule. This results in significant diuresis, with renal excretion of water, sodium chloride, magnesium, hydrogen, and calcium. Furosemide is commonly used for the clinical management of edema secondary to heart failure, treatment of hypertension, and treatment of hepatic or renal disease. Therapeutic effects include diuresis and lowering of blood pressure.

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RESEARCH NOTE

How Prevalent Is Chronic Dehydration in Elders?

Previous research has documented that dehydration is a problem in hospitalized elders, and low fluid intake has been documented to be a problem in nursing home residents. The authors questioned whether chronic dehydration is also a problem in elders living in the community. The researchers conducted a descriptive, retrospective study of 185 elders ranging from 75 to 100 years old. This group of elders visited a hospital emergency department during a 1-month period of time. Dehydration was defined as a ratio of blood urea nitrogen to creatine (BUN:Cr) greater than 20:1. Forty-eight percent of the group were dehydrated on admission to the emergency department. The elders from a residential facility were most likely to be dehydrated (65%); however, 44% of the elders living in the community were dehydrated.

Electrolyte Imbalances The most common and most significant electrolyte imbalances involve sodium, potassium, calcium, magnesium, chloride, and phosphate.

Sodium Sodium (Na⫹), the most abundant cation in the extracellular fluid, not only moves into and out of the body but also moves in careful balance among the three fluid compartments. It is found in most body secretions, for example, saliva, gastric and intestinal secretions, bile, and pancreatic fluid. Therefore, continuous excretion of any of these fluids, such as via intestinal suction, can result in a sodium deficit. Because of its role in regulating water balance, sodium imbalances usually are accompanied by water imbalance. Hyponatremia is a sodium deficit, or serum sodium level of less than 135 mEq/L, and is, in acute care settings, a common electrolyte imbalance. Because of sodium’s role in determining the osmolality of ECF, hyponatremia typically results in a low serum osmolality. Water is drawn out of the vascular compartment into interstitial tissues and the cells (Figure 52-12 ■, A), causing the clinical manifestations associated with this disorder. As sodium levels decrease, the brain and nervous system are affected by cellular edema. Severe hyponatremia, serum levels below 110 mEq/L, is a medical emergency and can lead to permanent neurological damage (Astle, 2005).

Cell shrinks as water is pulled out into ECF

Cell swells as water is pulled in from ECF H2O H2O

H2O

H2O A

B Hyponatremia: Na+less than 135 mEq/L

Hypernatremia: Na+greater than 145 mEq/L

Figure 52-12 ■ The extracellular sodium level affects cell size. A, In hyponatremia, cells swell; B, in hypernatremia, cells shrink in size.

IMPLICATIONS The results demonstrated that dehydration is a problem with both elders living in the community as well as elders living in residential facilities. Prevention of dehydration is an important intervention for nurses working with elders. Nursing interventions need to include talking with elders and their families about the dangers of dehydration and suggesting strategies to prevent dehydration. Note: From “Unrecognized Chronic Dehydration in Older Adults. Examining Prevalence Rate and Risk Factors,” by J. A. Bennett, V. Thomas, and B. Riegel, 2004, Journal of Gerontological Nursing, 30(1), pp. 22–28. Copyright © 2004 SLACK, Inc. Reprinted with permission.

Hypernatremia is excess sodium in ECF, or a serum sodium of greater than 145 mEq/L. Because the osmotic pressure of extracellular fluid is increased, fluid moves out of the cells into the ECF (Figure 52-12 ■, B). As a result, the cells become dehydrated. Like hyponatremia, the primary manifestations of hypernatremia are neurological in nature. It is important to note that a person’s thirst mechanism protects against hypernatremia. For example, when an individual becomes thirsty, the body is stimulated to drink water which helps correct the hypernatremia. Clients at risk for hypernatremia are those who are unable to access water (e.g., unconscious, unable to request fluids such as infants or elders with dementia, or ill clients with an impaired thirst mechanism). Table 52–6 lists risk factors and clinical signs for hyponatremia and hypernatremia.

Potassium Although the amount of potassium (K⫹) in extracellular fluid is small, it is vital to normal neuromuscular and cardiac function. Normal renal function is important for maintenance of potassium balance as 80% of potassium is excreted by the kidneys. Potassium must be replaced daily to maintain its balance. Normally, potassium is replaced in food. See previous Box 52–1 on page 1431 for a review of foods high in potassium. Hypokalemia is a potassium deficit or a serum potassium level of less than 3.5 mEq/L. Gastrointestinal losses of potassium through vomiting and gastric suction are common causes of hypokalemia, as are the use of potassium-wasting diuretics, such as thiazide diuretics or loop diuretics (e.g., furosemide). Symptoms of hypokalemia are usually mild until the level drops below 3 mEq/L unless the decrease in potassium was rapid. When the decrease is gradual, the body compensates by shifting potassium from the intracellular environment into the serum. Hyperkalemia is a potassium excess or a serum potassium level greater than 5.0 mEq/L. Hyperkalemia is less common than hypokalemia and rarely occurs in clients with normal renal function. It is, however, more dangerous than hypokalemia and can lead to cardiac arrest. As with hypokalemia, symptoms are more severe and occur at lower levels when the increase in potassium is abrupt. Table 52–6 lists risk factors and clinical signs for hypokalemia and hyperkalemia.

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TABLE 52–6

Electrolyte Imbalances

RISK FACTORS

CLINICAL MANIFESTATIONS

NURSING INTERVENTIONS

Lethargy, confusion, apprehension Muscle twitching Abdominal cramps Anorexia, nausea, vomiting Headache Seizures, coma Laboratory findings: Serum sodium below 135 mEq/L Serum osmolality below 280 mOsm/kg

Assess clinical manifestations. Monitor fluid intake and output. Monitor laboratory data (e.g., serum sodium). Assess client closely if administering hypertonic saline solutions. Encourage food and fluid high in sodium if permitted (e.g., table salt, bacon, ham, processed cheese). Limit water intake as indicated.

Thirst Dry, sticky mucous membranes Tongue red, dry, swollen Weakness

Monitor fluid intake and output. Monitor behavior changes (e.g., restlessness, disorientation). Monitor laboratory findings (e.g., serum sodium). Encourage fluids as ordered. Monitor diet as ordered (e.g., restrict intake of salt and foods high in sodium).

Hyponatremia Loss of sodium Gastrointestinal fluid loss ■ Sweating ■ Use of diuretics ■

Gain of water ■ Hypotonic tube feedings ■ Excessive drinking of water ■ Excess IV D5W (dextrose in water) administration Syndrome of inappropriate ADH (SIADH) ■ Head injury ■ AIDS ■ Malignant tumors Hypernatremia Loss of water ■ Insensible water loss (hyperventilation or fever) ■ Diarrhea ■ Water deprivation Gain of sodium ■ Parenteral administration of saline solutions ■ Hypertonic tube feedings without adequate water ■ Excessive use of table salt (1 tsp contains 2,300 mg of sodium) Conditions such as ■ Diabetes insipidus ■ Heat stroke

Severe hypernatremia: ■ Fatigue, restlessness ■ Decreasing level of consciousness ■ Disorientation ■ Convulsions Laboratory findings: Serum sodium above 145 mEq/L Serum osmolality above 300 mOsm/kg

Hypokalemia Loss of potassium ■ Vomiting and gastric suction ■ Diarrhea ■ Heavy perspiration ■ Use of potassium-wasting drugs (e.g., diuretics) ■ Poor intake of potassium (as with debilitated clients, alcoholics, anorexia nervosa) ■ Hyperaldosteronism

Muscle weakness, leg cramps Fatigue, lethargy Anorexia, nausea, vomiting Decreased bowel sounds, decreased bowel motility Cardiac dysrhythmias Depressed deep-tendon reflexes Weak, irregular pulses Laboratory findings: Serum potassium below 3.5 mEq/L Arterial blood gases (ABGs) may show alkalosis T wave flattening and ST segment depression on ECG

Monitor heart rate and rhythm. Monitor clients receiving digitalis (e.g., digoxin) closely, because hypokalemia increases risk of digitalis toxicity. Administer oral potassium as ordered with food or fluid to prevent gastric irritation. Administer IV potassium solutions at a rate no faster than 10–20 mEq/h; never administer undiluted potassium intravenously. For clients receiving IV potassium, monitor for pain and inflammation at the injection site. Teach client about potassium-rich foods. Teach clients how to prevent excessive loss of potassium (e.g., through abuse of diuretics and laxatives).

Gastrointestinal hyperactivity, diarrhea Irritability, apathy, confusion Cardiac dysrhythmias or arrest Muscle weakness, areflexia (absence of reflexes) Decreased heart rate; Irregular pulse

Closely monitor cardiac status and ECG. Administer diuretics and other medications such as glucose and insulin as ordered. Hold potassium supplements and K⫹ conserving diuretics.

Hyperkalemia Decreased potassium excretion Renal failure ■ Hypoaldosteronism ■ Potassium-conserving diuretics High potassium intake ■

continued on page 1440

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TABLE 52–6

Electrolyte Imbalances—continued

RISK FACTORS

CLINICAL MANIFESTATIONS

NURSING INTERVENTIONS

Paresthesias and numbness in extremities Laboratory findings: Serum potassium above 5.0 mEq/L Peaked T wave, widened QRS on ECG

Monitor serum K⫹ levels carefully; a rapid drop may occur as potassium shifts into the cells. Teach clients to avoid foods high in potassium and salt substitutes.

Numbness, tingling of the extremities and around the mouth Muscle tremors, cramps; if severe can progress to tetany and convulsions Cardiac dysrhythmias; decreased cardiac output Positive Trousseau’s and Chvostek’s signs (see Table 52–8) Confusion, anxiety, possible psychoses Hyperactive deep tendon reflexes Laboratory findings: Serum calcium less than 8.5 mg/dL or 4.5 mEq/L (total) Lengthened QT intervals Prolonged ST segments

Closely monitor respiratory and cardiovascular status. Take precautions to protect a confused client. Administer oral or parenteral calcium supplements as ordered. When administering intravenously, closely monitor cardiac status and ECG during infusion. Teach clients at high risk for osteoporosis about ■ Dietary sources rich in calcium. ■ Recommendation for 1,000–1,500 mg of calcium per day. ■ Calcium supplements. ■ Regular exercise. ■ Estrogen replacement therapy for postmenopausal women.

Lethargy, weakness Depressed deep-tendon reflexes Bone pain Anorexia, nausea, vomiting Constipation Polyuria, hypercalciuria Flank pain secondary to urinary calculi Dysrhythmias, possible heart block Laboratory findings: Serum calcium greater than 10.5 mg/dL or 5.5 mEq/L (total) Shortened QT intervals Shortened ST segments

Increase client movement and exercise. Encourage oral fluids as permitted to maintain a dilute urine. Teach clients to limit intake of food and fluid high in calcium. Encourage ingestion of fiber to prevent constipation. Protect a confused client; monitor for pathologic fractures in clients with long-term hypercalcemia. Encourage intake of acid-ash fluids (e.g., prune or cranberry juice) to counteract deposits of calcium salts in the urine.

Neuromuscular irritability with tremors Increased reflexes, tremors, convulsions Positive Chvostek’s and Trousseau’s signs (see Table 52–8)

Assess clients receiving digitalis for digitalis toxicity. Hypomagnesemia increases the risk of toxicity.

Tachycardia, elevated blood pressure, dysrhythmias Disorientation and confusion Vertigo Anorexia, dysphagia Respiratory difficulties Laboratory findings: Serum magnesium below 1.5 mEq/L Prolonged PR intervals, widened QRS complexes, prolonged QT intervals, depressed ST segments, broad flattened T waves, prominent U waves

Take protective measures when there is a possibility of seizures. ■ Assess the client’s ability to swallow water prior to initiating oral feeding. ■ Initiate safety measures to prevent injury during seizure activity. ■ Carefully administer magnesium salts as ordered. Encourage clients to eat magnesium-rich foods if permitted (e.g., whole grains, meat, seafood, and green leafy vegetables). Refer clients to alcohol treatment programs as indicated.

Hyperkalemia—continued Excessive use of K⫹ containing salt substitutes ■ Excessive or rapid IV infusion of potassium ■ Potassium shift out of the tissue cells into the plasma (e.g., infections, burns, acidosis) ■

Hypocalcemia Surgical removal of the parathyroid glands Conditions such as ■ Hypoparathyroidism ■ Acute pancreatitis ■ Hyperphosphatemia ■ Thyroid carcinoma Inadequate vitamin D intake ■ Malabsorption ■ Hypomagnesemia ■ Alkalosis ■ Sepsis ■ Alcohol abuse Hypercalcemia Prolonged immobilization Conditions such as ■ Hyperparathyroidism ■ Malignancy of the bone ■ Paget’s disease ■

Hypomagnesemia Excessive loss from the gastrointestinal tract (e.g., from nasogastric suction, diarrhea, fistula drainage) ■ Long-term use of certain drugs (e.g., diuretics, aminoglycoside antibiotics) Conditions such as ■ Chronic alcoholism ■ Pancreatitis ■ Burns ■

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TABLE 52–6

Electrolyte Imbalances—continued

RISK FACTORS

CLINICAL MANIFESTATIONS

NURSING INTERVENTIONS

Peripheral vasodilation, flushing Nausea, vomiting Muscle weakness, paralysis Hypotension, bradycardia Depressed deep-tendon reflexes Lethargy, drowsiness Respiratory depression, coma Respiratory and cardiac arrest if hypermagnesemia is severe Laboratory findings: Serum magnesium above 2.5 mEq/L Electrocardiogram showing prolonged QT interval, prolonged PR interval, widened QRS complexes, tall T waves

Monitor vital signs and level of consciousness when clients are at risk. If patellar reflexes are absent, notify the primary care provider. Advise clients who have renal disease to contact their primary care provider before taking over-the-counter drugs.

Hypermagnesemia Abnormal retention of magnesium, as in ■ Renal failure ■ Adrenal insufficiency ■ Treatment with magnesium salts

CLINICAL ALERT Potassium may be given intravenously for severe hypokalemia. It must ALWAYS be diluted appropriately and NEVER be given IV push. Potassium that is to be given IV should be mixed in the pharmacy and doublechecked prior to administration by two nurses. The usual concentration of IV potassium is 20 to 40 mEq/L. ■

Calcium Regulating levels of calcium (Ca2⫹) in the body is more complex than the other major electrolytes so calcium balance can be affected by many factors. Imbalances of this electrolyte are relatively common. Hypocalcemia is a calcium deficit, or a total serum calcium level of less than 8.5 mg/dL or an ionized calcium level of less than 4.0 mg/dL. Severe depletion of calcium can cause tetany with muscle spasms and paresthesias (numbness and tingling

A. Positive Chvostek's Sign

around the mouth and hands and feet) and can lead to convulsions. Two signs indicate hypocalcemia: The Chvostek’s sign is contraction of the facial muscles that is produced by tapping the facial nerve in front of the ear (Figure 52-13 ■, A). Trousseau’s sign is a carpal spasm that occurs by inflating a blood pressure cuff on the upper arm to 20 mm Hg greater than the systolic pressure for 2 to 5 minutes (Figure 52-13 ■, B). Clients at greatest risk for hypocalcemia are those whose parathyroid glands have been removed. This is frequently associated with total thyroidectomy or bilateral neck surgery for cancer. Low serum magnesium levels (hypomagnesemia) and chronic alcoholism also increase the risk of hypocalcemia. Hypercalcemia, or total serum calcium levels greater than 10.5 mg/dL, or an ionized calcium level of greater than 5.0 mg/dL, most often occurs when calcium is mobilized from the bony skeleton. This may be due to malignancy or prolonged immobilization.

B. Positive Trousseau's Sign

Figure 52-13 ■ A, Positive Chvostek’s sign. B, Positive Trousseau’s sign. From Lemone, Priscilla; Burke, Karen M., Medical Surgical Nursing: Critical Thinking in Client Care, 3rd ed © 2004. Reproduced with permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

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The risk factors and clinical manifestations related to calcium imbalances are found in Table 52–6.

serum phosphate levels may experience numbness and tingling around the mouth and in the fingertips, muscle spasms, and tetany.

Magnesium

Acid–Base Imbalances

Magnesium (Mg2⫹) imbalances are relatively common in hospitalized clients, although they may be unrecognized. Hypomagnesemia is a magnesium deficiency, or a total serum magnesium level of less than 1.5 mEq/L. It occurs more frequently than hypermagnesemia. Chronic alcoholism is the most common cause of hypomagnesemia. Magnesium deficiency also may aggravate the manifestations of alcohol withdrawal, such as delirium tremens (DTs). Hypermagnesemia is present when the serum magnesium level rises above 2.5 mEq/L. It is due to increased intake or decreased excretion. It is often iatrogenic, that is, a result of overzealous magnesium therapy. Table 52–6 lists risk factors and manifestations for clients with altered magesium balance.

Chloride Because of the relationship between sodium ions and chloride ions (Cl⫺), imbalances of chloride commonly occur in conjunction with sodium imbalances. Hypochloremia is a decreased serum chloride level, in adults a level below 95 mEq/L, and is usually related to excess losses of chloride ion through the GI tract, kidneys, or sweating. Hypochloremic clients are at risk for alkalosis and may experience muscle twitching, tremors, or tetany. Conditions that cause sodium retention also can lead to a high serum chloride level or hyperchloremia, in adults a level above 108 mEq/L. Excess replacement of sodium chloride or potassium chloride are additional risk factors for high serum chloride levels. The manifestations of hyperchloremia include acidosis, weakness, and lethargy, with a risk of dysrhythmias and coma.

Phosphate The phosphate anion PO4⫺ is found in both intracellular and extracellular fluid. Most of the phosphorus (P⫹) in the body exists as PO4⫺. Phosphate is critical for cellular metabolism because it is a major component of adenosine triphosphate (ATP). Phosphate imbalances frequently are related to therapeutic interventions for other disorders. Glucose and insulin administration and total parenteral nutrition can cause phosphate to shift into the cells from extracellular fluid compartments, leading to hypophosphatemia, defined in adults as a total serum phosphate level less than 2.5 mg/dL. Alcohol withdrawal, acid–base imbalances, and the use of antacids that bind with phosphate in the GI tract are other possible causes of low serum phosphate levels. Manifestations of hypophosphatemia include paresthesias, muscle weakness and pain, mental changes, and possible seizures. Hyperphosphatemia, defined in adults as a total serum phosphate level greater than 4.5 mg/dL, occurs when phosphate shifts out of the cells into extracellular fluids (e.g., due to tissue trauma or chemotherapy for malignant tumors), in renal failure, or when excess phosphate is administered or ingested. Infants who are fed cow’s milk are at risk for hyperphosphatemia, as are people using phosphate-containing enemas or laxatives. Clients who have high

Acid–base imbalances generally are classified as respiratory or metabolic by the general or underlying cause of the disorder. Carbonic acid levels are normally regulated by the lungs through the retention or excretion of carbon dioxide, and problems of regulation lead to respiratory acidosis or alkalosis. Bicarbonate and hydrogen ion levels are regulated by the kidneys, and problems of regulation lead to metabolic acidosis or alkalosis. Healthy regulatory systems will attempt to correct acid–base imbalances, a process called compensation.

Respiratory Acidosis Hypoventilation and carbon dioxide retention cause carbonic acid levels to increase and the pH to fall below 7.35, a condition known as respiratory acidosis. Serious lung diseases such as asthma and COPD are common causes of respiratory acidosis. Central nervous system depression due to anesthesia or a narcotic overdose can sufficiently slow the respiratory rate so that carbon dioxide is retained. When respiratory acidosis occurs, the kidneys retain bicarbonate to restore the normal carbonic acid to bicarbonate ratio. Recall, however, that the kidneys are relatively slow to respond to changes in acid–base balance, so this compensatory response may require hours to days to restore the normal pH.

Respiratory Alkalosis When a person hyperventilates, more carbon dioxide than normal is exhaled, carbonic acid levels fall, and the pH rises to greater than 7.45. This condition is termed respiratory alkalosis. Psychogenic or anxiety-related hyperventilation is a common cause of respiratory alkalosis. Other causes include fever and respiratory infections. In respiratory alkalosis, the kidneys will excrete bicarbonate to return the pH to within the normal range. Often, however, the cause of the hyperventilation is eliminated and the pH returns to normal before renal compensation occurs.

Metabolic Acidosis When bicarbonate levels are low in relation to the amount of carbonic acid in the body, the pH falls and metabolic acidosis develops. This may develop because of renal failure and the inability of the kidneys to excrete hydrogen ion and produce bicarbonate. It also may occur when too much acid is produced in the body, for example, in diabetic ketoacidosis or starvation when fat tissue is broken down for energy. Metabolic acidosis stimulates the respiratory center, and the rate and depth of respirations increase. Carbon dioxide is eliminated and carbonic acid levels fall, minimizing the change in pH. This respiratory compensation occurs within minutes of the pH imbalance.

Metabolic Alkalosis In metabolic alkalosis, the amount of bicarbonate in the body exceeds the normal 20-to-1 ratio. Ingestion of bicarbonate of soda as an antacid is one cause of metabolic alkalosis. Another

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ANATOMY & PHYSIOLOGY REVIEW

Gas Exchange Bronchiole Pulmonary vein

Pulmonary artery branch

CO2

O2

Alveolar wall

CO2 From Turley, Susan M., Medical Language, 1st ed., © 2002. Reproduced with permission of Pearson Education, Inc., Upper Saddle River, New Jersey.

Blood

O2

Capillary wall Red blood cell O2 molecule CO2 molecule

QUESTIONS

1. 2. 3. 4. 5. 6.

Hypoventilation can affect gas exchange. What are some causes of hypoventilation? How does the shallow breathing from hypoventilation cause the PaCO2 to increase and the pH to decrease? ABGs that indicate an increased PaCO2 and a decreased pH reflect which acid–base imbalance? Hyperventilation can also affect gas exchange. What are some causes of hyperventilation? How does hyperventilation cause a decreased PaCO2 and increased pH? ABGs that indicate a decreased PaCO2 and an increased pH reflect which acid–base imbalance?

cause is prolonged vomiting with loss of hydrochloric acid from the stomach. The respiratory center is depressed in metabolic alkalosis, and respirations slow and become more shallow. Carbon dioxide is retained and carbonic acid levels increase, helping balance the excess bicarbonate. The risk factors and manifestations for acid–base imbalances are listed in Table 52–7.

NURSING MANAGEMENT Assessing Assessing clients for fluid, electrolyte, and acid–base balance and imbalances is an important nursing care function. Components of the assessment include (a) the nursing history, (b) physical assessment of the client, (c) clinical measurements, and (d) review of laboratory test results.

Nursing History The nursing history is particularly important for identifying clients who are at risk for fluid, electrolyte, and acid–base imbalances. The current and past medical history reveal conditions such as chronic lung disease or diabetes mellitus that can disrupt normal balances. Medications prescribed to treat acute or chronic conditions (e.g., diuretic therapy for hypertension) also may place the client at risk for altered homeostasis. Functional, developmental, and socioeconomic factors must also be considered in assessing the client’s risk. Older people and very young children, clients who must depend on others to meet their needs for food and fluid intake, and people who cannot afford or do not have the means to cook food for a balanced diet (e.g., homeless people) are at greater risk for fluid and electrolyte imbalances. Common risk factors are listed in Box 52–3. When obtaining the nursing history, the nurse needs to not only recognize risk factors but also elicit data about the client’s

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TABLE 52–7

Acid–Base Imbalances

RISK FACTORS

CLINICAL MANIFESTATIONS

NURSING INTERVENTIONS

Respiratory Acidosis Acute lung conditions that impair alveolar gas exchange (e.g., pneumonia, acute pulmonary edema, aspiration of foreign body, near-drowning) Chronic lung disease (e.g., asthma, cystic fibrosis, or emphysema) Overdose of narcotics or sedatives that depress respiratory rate and depth Brain injury that affects the respiratory center Airway obstruction Mechanical chest injury

Increased pulse and respiratory rates Headache, dizziness Confusion, decreased level of consciousness (LOC) Convulsions Warm, flushed skin Chronic: Weakness Headache Laboratory findings: Arterial blood pH less than 7.35 PaCO2 above 45 mm Hg HCO3⫺ normal or slightly elevated in acute; above 26 mEq/L in chronic

Frequently assess respiratory status and lung sounds. Monitor airway and ventilation; insert artificial airway and prepare for mechanical ventilation as necessary. Administer pulmonary therapy measures such as inhalation therapy, percussion and postural drainage, bronchodilators, and antibiotics as ordered. Monitor fluid intake and output, vital signs, and arterial blood gases. Administer narcotic antagonists as indicated. Maintain adequate hydration (2–3 L of fluid per day).

Complaints of shortness of breath, chest tightness Light-headedness with circumoral paresthesias and numbness and tingling of the extremities Difficulty concentrating Tremulousness, blurred vision Laboratory findings (in uncompensated respiratory alkalosis): Arterial blood pH above 7.45 PaCO2 less than 35 mm Hg

Monitor vital signs and ABGs. Assist client to breathe more slowly. Help client breathe in a paper bag or apply a rebreather mask (to inhale CO2).

Kussmaul’s respirations (deep, rapid respirations) Lethargy, confusion Headache Weakness Nausea and vomiting Laboratory findings: Arterial blood pH below 7.35 Serum bicarbonate less than 22 mEq/L PaCO2 less than 38 mm Hg with respiratory compensation

Monitor ABG values, intake and output, and LOC. Administer IV sodium bicarbonate carefully if ordered. Treat underlying problem as ordered.

Decreased respiratory rate and depth Dizziness Circumoral paresthesias, numbness and tingling of the extremities Hypertonic muscles, tetany Laboratory findings: Arterial blood pH above 7.45 Serum bicarbonate greater than 26 mEq/L PaCO2 higher than 45 mm Hg with respiratory compensation

Monitor intake and output closely. Monitor vital signs, especially respirations, and LOC. Administer ordered IV fluids carefully. Treat underlying problem.

Respiratory Alkalosis Hyperventilation due to ■ Extreme anxiety ■ Elevated body temperature ■ Overventilation with a mechanical ventilator ■ Hypoxia ■ Salicylate overdose Brain stem injury Fever Increased basal metabolic rate Metabolic Acidosis Conditions that increase nonvolatile acids in the blood (e.g., renal impairment, diabetes mellitus, starvation) Conditions that decrease bicarbonate (e.g., prolonged diarrhea) Excessive infusion of chloride-containing IV fluids (e.g., NaCl) Excessive ingestion of acids such as salicylates Cardiac arrest Metabolic Alkalosis Excessive acid losses due to ■ Vomiting ■ Gastric suction Excessive use of potassium-losing diuretics Excessive adrenal corticoid hormones due to ■ Cushing’s syndrome ■ Hyperaldosteronism Excessive bicarbonate intake from ■ Antacids ■ Parenteral NaHCO3

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BOX 52–3

Common Risk Factors for Fluid, Electrolyte, and Acid–Base Imbalances

CHRONIC DISEASES AND CONDITIONS ■ Chronic lung disease (COPD, asthma, cystic fibrosis) ■ Heart failure ■ Kidney disease ■ Diabetes mellitus ■ Cushing’s syndrome or Addison’s disease ■ Cancer ■ Malnutrition, anorexia nervosa, bulimia ■ Ileostomy ACUTE CONDITIONS ■ Acute gastroenteritis ■ Bowel obstruction ■ Head injury or decreased level of consciousness ■ Trauma such as burns or crushing injuries ■ Surgery ■ Fever, draining wounds, fistulas

MEDICATIONS Diuretics ■ Corticosteroids ■ Nonsteroidal anti-inflammatory drugs ■

TREATMENTS ■ Chemotherapy ■ IV therapy and total parenteral nutrition ■ Nasogastric suction ■ Enteral feedings ■ Mechanical ventilation OTHER FACTORS ■ Age: Very old or very young ■ Inability to access food and fluids independently

food and fluid intake, fluid output, and the presence of signs or symptoms suggestive of altered fluid and electrolyte balance. The Assessment Interview provides examples of questions to elicit information regarding fluid, electrolyte, and acid–base balance.

mation obtained in the nursing history. The focused physical assessment is summarized in Table 52–8 on page 1446. Refer to Tables 52–5 through 52–8 for possible abnormal findings related to specific imbalances.

Physical Assessment

Three simple clinical measurements that the nurse can initiate without a primary care provider’s order are daily weights, vital signs, and fluid intake and output.

Physical assessment to evaluate a client’s fluid, electrolyte, and acid–base status focuses on the skin, the oral cavity and mucous membranes, the eyes, the cardiovascular and respiratory systems, and neurologic and muscular status. Data from this physical assessment are used to expand and verify infor-

ASSESSMENT INTERVIEW

Clinical Measurements

DAILY WEIGHTS. Daily weight measurements provide a rela-

tively accurate assessment of a client’s fluid status. Significant changes in weight over a short time (e.g., more than 5 pounds

Fluid, Electrolyte, and Acid–Base Balance

CURRENT AND PAST MEDICAL HISTORY Are you currently seeing a health care provider for treatment of any chronic diseases such as kidney disease, heart disease, high blood pressure, diabetes insipidus, or thyroid or parathyroid disorders? ■ Have you recently experienced any acute conditions such as gastroenteritis, severe trauma, head injury, or surgery? If so, describe them.

■

■

MEDICATIONS AND TREATMENTS Are you currently taking any medications on a regular basis such as diuretics, steroids, potassium supplements, calcium supplements, hormones, salt substitutes, or antacids? ■ Have you recently undergone any treatments such as dialysis, parenteral nutrition, or tube feedings or been on a ventilator? If so, when and why? ■

FOOD AND FLUID INTAKE How much and what type of fluids do you drink each day? Describe your diet for a typical day. (Pay particular attention to the client’s intake of foods high in sodium content, of protein, and of whole grains, fruits, and vegetables.) ■ Have there been any recent changes in your food or fluid intake, for example, as a result of following a weight-loss program? ■ Are you on any type of restricted diet? ■ ■

Has your food or fluid intake recently been affected by changes in appetite, nausea, or other factors such as pain or difficulty breathing?

FLUID OUTPUT Have you noticed any recent changes in the frequency or amount of urine output? ■ Have you recently experienced any problems with vomiting, diarrhea, or constipation? If so, when and for how long? ■ Have you noticed any other unusual fluid losses such as excessive sweating? ■

FLUID, ELECTROLYTE, AND ACID–BASE IMBALANCES Have you gained or lost weight in recent weeks? Have you recently experienced any symptoms such as excessive thirst, dry skin or mucous membranes, dark or concentrated urine, or low urine output? ■ Do you have problems with swelling of your hands, feet, or ankles? Do you ever have difficulty breathing, especially when lying down or at night? How many pillows do you use to sleep? ■ Have you recently experienced any of the following symptoms: difficulty concentrating or confusion; dizziness or feeling faint; muscle weakness, twitching, cramping, or spasm; excessive fatigue; abnormal sensations such as numbness, tingling, burning, or prickling; abdominal cramping or distention; heart palpitations? ■ ■

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TABLE 52–8

Focused Physical Assessment for Fluid, Electrolyte, or Acid–Base Imbalances

SYSTEM Skin

ASSESSMENT FOCUS Color, temperature, moisture

TECHNIQUE Inspection, palpation

Turgor

Gently pinch up a fold of skin over sternum or inner aspect of thigh for adults, on the abdomen or medial thigh for children Inspect for visible swelling around eyes, in fingers, and in lower extremities Compress the skin over the dorsum of the foot, around the ankles, over the tibia, in the sacral area Inspection

Edema

Mucous membranes

Color, moisture

Eyes Fontanels (infant)

Firmness Firmness, level

Cardiovascular system

Heart rate Peripheral pulses Blood pressure

Gently palpate eyeball with lid closed Inspect and gently palpate anterior fontanel Auscultation, cardiac monitor

Respiratory system

Respiratory rate and pattern

Palpation Auscultation of Korotkoff’s sounds BP assessment lying and standing Palpation Inspection of jugular veins and hand veins Inspection

Neurologic

Lung sounds Level of consciousness (LOC)

Auscultation Observation, stimulation

Orientation, cognition

Questioning

Motor function Reflexes Abnormal reflexes

Strength testing Deep-tendon reflex (DTR) testing Chvostek’s sign: Tap over facial nerve about 2 cm anterior to tragus of ear Trousseau’s sign: Inflate a blood pressure cuff on the upper arm to 20 mm Hg greater than the systolic pressure, leave in place for 2 to 5 minutes

Capillary refill Venous filling

in a week or less) are indicative of acute fluid changes. Each kilogram (2.2 lb) of weight gained or lost is equivalent to 1 L of fluid gained or lost. Such fluid gains or losses indicate changes in total body fluid volume rather than in any specific compartment, such as the intravascular compartment. Rapid losses or gains of 5% to 8% of total body weight indicate moderate to severe fluid volume deficits or excesses. To obtain accurate weight measurements, the nurse should balance the scale before each use and weigh the client (a) at the same time each day (e.g., before breakfast and after the first void), (b) wearing the same or similar clothing, and (c) on the same scale. The type of scale (i.e., standing, bed, chair) should be documented. Regular assessment of weight is particularly important for clients in the community and extended care facilities who are at

POSSIBLE ABNORMAL FINDINGS Flushed, warm, very dry Moist or diaphoretic Cool and pale Poor turgor: Skin remains tented for several seconds instead of immediately returning to normal position Skin around eyes is puffy, lids appear swollen; rings are tight; shoes leave impressions on feet Depression remains (pitting): see scale for describing edema in Figure 52-11 Mucous membranes dry, dull in appearance; tongue dry and cracked Eyeball feels soft to palpation Fontanel bulging, firm Fontanel sunken, soft Tachycardia, bradycardia; irregular; dysrhythmias Weak and thready; bounding Hypotension Postural hypotension Slowed capillary refill Jugular venous distention; flat jugular veins, poor venous refill Increased or decreased rate and depth of respirations Crackles or moist rales Decreased LOC, lethargy, stupor, or coma Disoriented, confused; difficulty concentrating Weakness, decreased motor strength Hyperactive or depressed DTRs Facial muscle twitching including eyelids and lips on side of stimulus Carpal spasm: contraction of hand and fingers on affected side

risk for fluid imbalance. For these clients, measuring intake and output may be impractical because of lifestyle or problems with incontinence. Regular weight measurement, either daily, every other day, or weekly, provides valuable information about the client’s fluid volume status. VITAL SIGNS. Changes in the vital signs may indicate, or in some cases precede, fluid, electrolyte, and acid–base imbalances. For example, elevated body temperature may be a result of dehydration or a cause of increased body fluid losses. Tachycardia is an early sign of hypovolemia. Pulse volume will decrease in FVD and increase in FVE. Irregular pulse rates may occur with electrolyte imbalances. Changes in respiratory rate and depth may cause respiratory acid–base im-

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balances or act as a compensatory mechanism in metabolic acidosis or alkalosis. Blood pressure, a sensitive measure to detect blood volume changes, may fall significantly with FVD and hypovolemia or increase with FVE. Postural, or orthostatic, hypotension may also occur with FVD and hypovolemia. To assess for orthostatic hypotension, measure the client’s blood pressure and pulse in a supine position. Allow the client to remain in that position for 3 to 5 minutes, leaving the blood pressure cuff on the arm. Stand the client up and immediately reassess the blood pressure and pulse. A drop of 10 to 15 mm Hg in the systolic blood pressure with a corresponding drop in diastolic pressure and an increased pulse rate (by 10 or more beats per minute) is indicative of orthostatic or postural hypotension. FLUID INTAKE AND OUTPUT. The measurement and recording of all fluid intake and output (I & O) during a 24-hour period provides important data about the client’s fluid and electrolyte balance. Generally, intake and output are measured for hospitalized at-risk clients. The unit used to measure intake and output is the milliliter (mL) or cubic centimeter (cc); these are equivalent metric units of measurement. In household measures, 30 mL is roughly equivalent to 1 fluid ounce, 500 mL is about 1 pint, and 1,000 mL is about 1 quart. To measure fluid intake, nurses convert household measures such as a glass, cup, or soup bowl to metric units. Most agencies provide conversion tables, since the sizes of dishes vary from agency to agency. Such a table is often provided on or with the bedside I & O record. Examples of equivalents are given in Box 52–4. Most agencies have a form for recording I & O, usually a bedside record on which the nurse lists all items measured and the quantities per shift (Figure 52-14 ■). Some agencies have another form for recording the specifics of intravenous fluids, such as the type of solution, additives, time started, amounts absorbed, and amounts remaining per shift. It is important to inform clients, family members, and all caregivers that accurate measurements of the client’s fluid in-

Figure 52-14 ■ A sample 24-hour fluid intake and output record.

take and output are required, explaining why and emphasizing the need to use a bedpan, urinal, commode, or in-toilet collection device (unless a urinary drainage system is in place). Instruct the client not to put toilet tissue into the container with urine. Clients who wish to be involved in recording fluid intake measurements need to be taught how to compute the values and what foods are considered fluids. To measure fluid intake, the nurse records on the I & O form each fluid item taken (if the client has not already done so), specifying the time and type of fluid. All of the following fluids need to be recorded: ■

BOX 52—4 Commonly Used Fluid Containers and Their Volumes Water glass Juice glass Cup Soup bowl Adult Child Teapot Creamer Large Small Water pitcher Jello, custard dish Ice cream dish Paper cup Large Small

200 mL 120 mL 180 mL

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180 mL 100 mL 240 mL

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90 mL 30 mL 1,000 mL 100 mL 120 mL

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200 mL 120 mL

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Oral fluids. Water, milk, juice, soft drinks, coffee, tea, cream, soup, and any other beverages. Include water taken with medications. To assess the amount of water taken from a water pitcher, measure what remains and subtract this amount from the volume of the full pitcher. Then refill the pitcher. Ice chips. Record the fluid as approximately one-half the volume of the ice chips. For example, if the ice chips fill a cup holding 200 mL and the client consumed all of the ice chips, the volume consumed would be recorded as 100 mL. Foods that are or tend to become liquid at room temperature. These include ice cream, sherbert, custard, and gelatin. Do not measure foods that are pureed, because purees are simply solid foods prepared in a different form. Tube feedings. Remember to include the 30- to 60-mL water flush at the end of intermittent feedings or during continuous feedings. Parenteral fluids. The exact amount of intravenous fluid administered is to be recorded, since some fluid containers may be overfilled. Blood transfusions are included. Intravenous medications. Intravenous medications that are prepared with solutions such as normal saline (NS) and are

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administered as an intermittent or continuous infusion must also be included (e.g., ceftazidime 1 g in 50 mL of sterile water). Most intravenous medications are mixed in 50 to 100 mL of solution. Catheter or tube irrigants. Fluid used to irrigate urinary catheters, nasogastric tubes, and intestinal tubes must be measured and recorded if not immediately withdrawn.

To measure fluid output, measure the following fluids (remember to observe appropriate infection control precautions): ■

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Urinary output. Following each voiding, pour the urine into a measuring container, observe the amount, and record it and the time of voiding on the I & O form. For clients with retention catheters, empty the drainage bag into a measuring container at the end of the shift (or at prescribed times if output is to be measured more often). Note and record the amount of urine output. In intensive care areas, urine output often is measured hourly. If the client is incontinent of urine, estimate and record these outputs. For example, for an incontinent client the nurse might record “Incontinent × 3” or “Drawsheet soaked in 12-in. diameter.” A more accurate estimate of the urine output of infants and incontinent clients may be obtained by first weighing diapers or incontinent pads that are dry, and then subtracting this weight from the weight of the soiled items. Each gram of weight left after subtracting is equal to 1 mL of urine. If urine is frequently soiled with feces, the number of voidings may be recorded rather than the volume of urine. Vomitus and liquid feces. The amount and type of fluid and the time need to be specified. Tube drainage, such as gastric or intestinal drainage. Wound drainage and draining fistulas. Wound drainage may be recorded by documenting the type and number of dressings or linen saturated with drainage or by measuring the exact amount of drainage collected in a vacuum drainage (e.g., Hemovac) or gravity drainage system.

Fluid intake and output measurements are totaled at the end of the shift (every 8 to 12 hours), and the totals are recorded in the client’s permanent record. In intensive care areas, the nurse may record intake and output hourly. Usually the staff on night shift totals the amounts of I & O recorded for each shift and records the 24-hour total. To determine whether the fluid output is proportional to fluid intake or whether there are any changes in the client’s fluid status, the nurse (a) compares the total 24-hour fluid output measurement with the total fluid intake measurement and (b) compares both to previous measurements. Urinary output is normally equivalent to the amount of fluids ingested; the usual range is 1,500 to 2,000 mL in 24 hours, or 40 to 80 mL in 1 hour (0.5 mL/kg/hour). Clients whose output substantially exceeds intake are at risk for fluid volume deficit. By contrast, clients whose intake substantially exceeds output are at risk for fluid volume excess. In assessing the client’s fluid balance it is important to consider additional factors that may affect intake and output. The client who is extremely diaphoretic or who has rapid, deep respirations has fluid losses that

BOX 52—5 Normal Electrolyte Values for Adults* VENOUS BLOOD Sodium Potassium Chloride Calcium (total) (ionized) Magnesium Phosphate (phosphorus) Serum osmolality

135–145 mEq/L 3.5–5.0 mEq/L 95–108 mEq/L 4.5–5.5 mEq/L or 8.5–10.5 mg/dL 56% of total calcium (2.5 mEq/L or 4.0–5.0 mg/dL) 1.5–2.5 mEq/L or 1.6–2.5 mg/dL 1.8–2.6 mEq/L or 2.5 – 4.5 mg/dL 280–300 mOsm/kg water

*

Normal laboratory values vary from agency to agency.

cannot be measured but must be considered in evaluating fluid status. When there is a significant discrepancy between intake and output or when fluid intake or output is inadequate (for example, a urine output of less than 500 mL in 24 hours or less than 0.5 mL per kilogram per hour in an adult), this information should be reported to the charge nurse or primary care provider.

Laboratory Tests Many laboratory studies are conducted to determine the client’s fluid, electrolyte, and acid–base status. Some of the more common tests are discussed here. SERUM ELECTROLYTES. Serum electrolyte levels are often

routinely ordered for any client admitted to the hospital as a screening test for electrolyte and acid–base imbalances. Serum electrolytes also are routinely assessed for clients at risk in the community, for example, clients who are being treated with a diuretic for hypertension or heart failure. The most commonly ordered serum tests are for sodium, potassium, chloride, magnesium, and bicarbonate ions. Normal values of commonly measured electrolytes are shown in Box 52–5. Some primary care providers use a diagram format for keeping track of the client’s electrolytes when documenting in their progress notes. See Figure 52-15 ■. A.

BUN Na

Cl

K

CO2

B.

CR

10 142

102

4.2

28 0.8

Figure 52-15 ■ A, Format for a diagram of serum electrolyte results. B, Example that may be seen in a primary care provider’s documentation notes.

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specialized skills. Because a high-pressure artery is used to obtain blood, it is important to apply pressure to the puncture site for 5 minutes after the procedure to reduce the risk of bleeding or bruising. Six measurements are commonly used to interpret arterial blood gas tests (Simpson, 2004):

OSMOLALITY. Serum osmolality is a measure of the solute

concentration of the blood. The particles included are sodium ions, glucose, and urea (blood urea nitrogen, or BUN). Serum osmolality can be estimated by doubling the serum sodium, because sodium and its associated chloride ions are the major determinants of serum osmolality. Serum osmolality values are used primarily to evaluate fluid balance. Normal values are 280 to 300 mOsm/kg. An increase in serum osmolality indicates a fluid volume deficit; a decrease reflects a fluid volume excess. Urine osmolality is a measure of the solute concentration of urine. The particles included are nitrogenous wastes, such as creatinine, urea, and uric acid. Normal values are 500 to 800 mOsm/kg. An increased urine osmolality indicates a fluid volume deficit; a decreased urine osmolality reflects a fluid volume excess.

URINE SPECIFIC GRAVITY. Specific gravity is an indicator of

URINE SODIUM AND CHLORIDE EXCRETION. These are indicators of renal perfusion and can provide useful information about a client’s fluid status. With hypovolemia, aldosterone will be secreted. This will cause reabsorption of sodium and chloride which will result in decreased levels of sodium and chloride, less than 20 mEq/L each (Elgart, 2004). ARTERIAL BLOOD GASES. Arterial blood gases (ABGs) are performed to evaluate the client’s acid–base balance and oxygenation. Arterial blood is used because it provides a truer reflection of gas exchange in the pulmonary system than venous blood. Blood gases may be drawn by laboratory technicians, respiratory therapy personnel, or nurses with

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Normal ABG values are listed in Box 52–6. Changes seen in common acid–base imbalances are summarized in Table 52–9. Note that although the PaO2 and SpO2 are important for assessing respiratory status, they generally do not provide useful information for assessing acid–base balance and so are not included in this table. When evaluating ABG results to determine acid–base balance, it is important to use a systematic approach such as the one outlined in Box 52–7. Nurses need to assess each measurement individually, then look at the interrelationships to determine what type of acid–base imbalance may be present.

BOX 52—6 Normal Values of Arterial Blood Gases* pH PaO2 PaCO2 HCO3⫺ Base excess O2 saturation

7.35–7.45 80–100 mm Hg 35–45 mm Hg 22–26 mEq/L ⫺2 to ⫹2 mEq/L 95–98%

* Some normal values will vary according to the kind of test carried out in the laboratory. Nurses are advised to use the normal values issued by the agency when interpreting laboratory results.

Arterial Blood Gases and Acid–Base Balance

urine concentration that can be performed quickly and easily by nursing personnel. Normal specific gravity ranges from 1.005 to 1.030 (usually 1.010 to 1.025). When the concentration of solutes in the urine is high, the specific gravity rises; in very dilute urine with few solutes, it is abnormally low.

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URINE pH. Measurement of urine pH may be obtained by laboratory analysis or by using a dipstick on a freshly voided specimen. Because the kidneys play a critical role in regulating acid–base balance, assessment of urine pH can be useful in determining whether the kidneys are responding appropriately to acid–base imbalances. Normally the pH of the urine is relatively acidic, averaging about 6.0, but a range of 4.6 to 8.0 is considered normal. In metabolic acidosis, urine pH should decrease as the kidneys excrete hydrogen ions; in metabolic alkalosis, the pH should increase.

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pH: a measure of the relative acidity or alkalinity of the blood. The greater the number of hydrogen ions, the more acidic the solution is. The normal range for pH is narrow, and death may ensue with pH values below 6.8 or above 7.8. PaO2: the pressure exerted by oxygen dissolved in the plasma of arterial blood; an indirect measure of blood oxygen content. This measure, representing one of the two forms in which oxygen is transported in the blood, accounts for only about 3% of oxygen content in the blood. PaCO2: the partial pressure of carbon dioxide in arterial plasma; the respiratory component of acid–base determination. Carbon dioxide is regulated by the lungs, and the PaCO2 is used to determine if an acid–base imbalance is respiratory in origin. Bicarbonate HCO3⫺: a measure of the metabolic component of acid–base balance. Base excess (BE): a calculated value of bicarbonate levels, also reflective of the metabolic component of acid–base balance. If the number is preceded by a plus sign, it is a base excess and indicates alkalosis; if preceded by a minus sign, it is a base deficit and indicates acidosis. Oxygen saturation (SpO2): the percentage of hemoglobin saturated (combined) with oxygen. This represents the other form in which oxygen is transported in the blood and accounts for about 97% of the oxygen in the blood.

Client with Suspected Electrolyte Imbalance Case Study

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COMPLETE BLOOD COUNT (CBC). The complete blood count, another basic screening test, includes information about the hematocrit (Hct). The hematocrit measures the volume (percentage) of whole blood that is composed of RBCs. Because the hematocrit is a measure of the volume of cells in relation to plasma, it is affected by changes in plasma volume. Thus the hematocrit increases with severe dehydration and decreases with severe overhydration. Normal hematocrit values are 40% to 54% (men) and 37% to 47% (women).

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TABLE 52–9

Arterial Blood Gas Values in Common Acid–Base Disorders

DISORDER Respiratory acidosis

pH PaCO2 HCO3⫺

ABG VALUES < 7.35 > 45 mm Hg (excess CO2 and carbonic acid) Normal; or >26 mEq/L with renal compensation

Respiratory alkalosis

pH PaCO2 HCO3⫺

> 7.45 < 35 mm Hg (inadequate CO2 and carbonic acid) Normal; or < 22 mEq/L with renal compensation

Metabolic acidosis

pH PaCO2

< 7.35 Normal; or < 35 mm Hg with respiratory compensation < 22 mEq/L (inadequate bicarbonate)

Metabolic alkalosis

HCO3⫺ pH PaCO2

> 7.45 Normal; or > 45 mm Hg with respiratory compensation > 26 mEq/L (excess bicarbonate)

HCO3⫺

Diagnosing

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NANDA includes the following diagnostic labels that relate to fluid and acid–base imbalances: ■

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Deficient Fluid Volume: Decreased intravascular, interstitial, and/or intracellular fluid. This refers to dehydration, water loss alone without change in sodium. Excess Fluid Volume: Increased isotonic fluid retention.

BOX 52—7

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Risk for Imbalanced Fluid Volume: At risk for a decrease, increase, or rapid shift from one to the other of intravascular, interstitial, and/or intracellular fluid. This refers to body fluid loss, gain, or both. Risk for Deficient Fluid Volume: At risk for experiencing vascular, cellular, or intracellular dehydration. Impaired Gas Exchange: Excess or deficit in oxygenation and/or carbon dioxide elimination at the alveolar-capillary membrane.

Interpreting ABGs — Do You Have a Match?

1. Look at each number separately. ■ Label the pH: ● If the pH is less than 7.35, the problem is acidosis. ● If the pH is greater than 7.45, the problem is alkalosis. ■ Label the PaCO2: ● If the PaCO2 is less than 35 mm Hg, more carbon dioxide is being exhaled than normal and indicates alkalosis. ● If the PaCO2 is greater than 45 mm Hg, less carbon dioxide is being exhaled than normal and indicates acidosis. ■ Label the bicarbonate: ● If the HCO3⫺ is less than 22 mEq/L, bicarbonate levels are lower than normal, indicating acidosis. ● If the HCO3⫺ is greater than 26 mEq/L, bicarbonate levels are higher than normal, indicating alkalosis. 2. Determine the cause of the acid–base imbalance. ■ Look at the pH—is it acidosis or alkalosis? 3. Determine if the origin of the imbalance is respiratory or metabolic. ■ Check the PaCO2 and HCO3⫺ which one MATCHES the same acid–base status as the pH? EXAMPLE pH ⫽ 7.33 (acidosis) PaCO2 ⫽ 55 (acidosis) HCO3 ⫽ 29 (alkalosis) Cause of imbalance (hint: look at pH) ⫽ acidosis. PaCO2 (acidosis) MATCHES the pH (acidosis) ⫽ respiratory problem Client has respiratory acidosis.

4. Look for evidence of compensation. ■ Look at the value that does NOT match the pH: ● If it (e.g., PaCO2 or HCO3 ) is within normal range, there is no compensation. ● If it (e.g., PaCO2 or HCO3 ) is above or below normal range, the body is compensating. EXAMPLES a. In respiratory acidosis (pH < 7.35, PaCO2 > 45 mm Hg), if the HCO3⫺ is greater than 26 mEq/L, the kidneys are retaining bicarbonate to minimize the acidosis: renal compensation. b. In respiratory alkalosis (pH > 7.45, PaCO2 < 35 mm Hg), if the HCO3⫺ is less than 22 mEq/L, the kidneys are excreting bicarbonate to minimize the alkalosis: again, renal compensation. c. In metabolic acidosis (pH < 7.35, HCO3⫺ < 22 mEq/L), if the PaCO2 is less than 35 mm Hg, carbon dioxide is being “blown off” to minimize the acidosis: respiratory compensation. d. In metabolic alkalosis (pH > 7.45, HCO3⫺ > 26 mEq/L), if the PaCO2 is greater than 45 mm Hg, carbon dioxide is being retained to compensate for excess base: again, respiratory compensation. Note: If the value that doesn’t match (e.g., PaCO2 or HCO3 ) is above or below normal and the pH is within normal range, the body has completely compensated. Complete compensation takes time to develop and is the result of a chronic condition (e.g., chronic respiratory acidosis with COPD).

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Impaired Oral Mucous Membrane related to fluid volume deficit. Impaired Skin Integrity related to dehydration and/or edema. Decreased Cardiac Output related to hypovolemia and/or cardiac dysrhythmias secondary to electrolyte imbalance (K⫹ or Mg2⫹). Ineffective Tissue Perfusion related to decreased cardiac output secondary to fluid volume deficit or edema. Activity Intolerance related to hypervolemia. Risk for Injury related to calcium shift out of bones into extracellular fluids. Acute Confusion related to electrolyte imbalance.

Planning When planning care the nurse identifies nursing interventions that will assist the client to achieve these broad goals: ■ ■ ■

Maintain or restore normal fluid balance. Maintain or restore normal balance of electrolytes in the intracellular and extracellular compartments. Maintain or restore pulmonary ventilation and oxygenation.

Prevent associated risks (tissue breakdown, decreased cardiac output, confusion, other neurologic signs).

Obviously, goals will vary according to the diagnosis and defining characteristics for each individual. Appropriate preventive and corrective nursing interventions that relate to these must be identified. Specific nursing activities can be selected to meet the client’s individual needs. Examples of application of these using NANDA, NIC, and NOC designations are shown in Identifying Nursing Diagnoses, Outcomes, and Interventions and in the Nursing Care Plan and the Concept Map at the end of this chapter. Examples of NIC interventions related to fluid, electrolyte, and acid–base balance include the following: ■ ■ ■ ■ ■

Acid–base management Electrolyte management Fluid monitoring Hypovolemia management Intravenous (IV) therapy

Specific nursing activities associated with each of these interventions can be selected to meet the individual needs of the client. Nursing activities to meet goals and outcomes related to fluid, electrolyte, and acid–base imbalances are discussed in the next section. These include (a) monitoring fluid intake and output, cardiovascular and respiratory status, and results of laboratory tests; (b) assessing the client’s weight; location and extent of edema, if present; skin turgor and skin status; specific gravity of urine; and level of consciousness and mental status;

IDENTIFYING NURSING DIAGNOSES, OUTCOMES, AND INTERVENTIONS Clients with Fluid Volume Excess DATA CLUSTER Tom Bricker, a 67-year-old pensioner who has a history of heart disease, has experienced a weight gain of 4 to 5 kg (9 to 11 lb) during the past month. He states his rings are too tight to remove, his ankles are swollen, his heart pounds at times, he gets breathless with exertion, and he feels bloated. Physical findings reveal jugular vein distention above 3 cm; delayed emptying of hand veins; bounding pulse (86); pitting edema in feet, ankles, and lower legs; and moist lung sounds (rales/crackles). NURSING DIAGNOSIS/ DEFINITION Excess Fluid Volume/ Increased isotonic fluid retention

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SAMPLE DESIRED OUTCOMES*/ DEFINITION Fluid Balance [0601]/Water balance in the intracellular and extracellular compartments of the body

INDICATORS Not compromised: ■ 24-hour intake and output ■ Stable body weight No: ■ Adventitious breath sounds ■ Neck vein distention

SELECTED INTERVENTIONS*/ DEFINITION Fluid Management [4120]/Promotion of fluid balance and prevention of complications resulting from abnormal or undesired fluid levels

SAMPLE NIC ACTIVITIES ■

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Assess location and extent of edema on scale from 1⫹ to 4⫹ Monitor for indications of fluid overload/retention (e.g., crackles, elevated BP, edema, neck vein distention) as appropriate Maintain accurate intake and output record Weigh daily and monitor trends Consult primary care provider if signs and symptoms of fluid volume excess persist or worsen

The NOC # for desired outcomes and the NIC # for nursing interventions are listed in brackets following the appropriate outcome or intervention. Outcomes, indicators, inter-

ventions, and activites selected are only a sample of those suggested by NOC and NIC and should be further individualized for each client.

Client with Heart Failure Care Plan Activity

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Clinical applications of selected diagnoses are shown in Identifying Nursing Diagnoses, Outcomes, and Interventions and in the Nursing Care Plan and the Concept Map at the end of this chapter. Fluid, electrolyte, and acid–base imbalances affect many other body areas and as a consequence may be the etiology of other nursing diagnoses, such as

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IDENTIFYING NURSING DIAGNOSES, OUTCOMES, AND INTERVENTIONS Clients with Impaired Gas Exchange DATA CLUSTER Fred Boysniak was admitted to emergency after being found with an empty bottle of morphine tablets by his bed. He appears very lethargic and stuporous; pulse is 120, respiration 12 and very shallow. Blood gases reveal pH of 7.28, PaCO2 49 mm Hg, and HCO3⫺ 25 mEq/L. NURSING DIAGNOSIS/ DEFINITION Impaired Gas Exchange/Excess or deficit in oxygenation and/or carbon dioxide elimination at the alveolar-capillary membrane

SAMPLE DESIRED OUTCOMES*/ DEFINITION Respiratory Status: Ventilation [0403]/ Movement of air in and out of the lungs

SELECTED INTERVENTIONS*/ DEFINITION

INDICATORS Not compromised ■ Depth of inspiration ■ Auscultated breath sounds

Acid–Base Management: Respiratory Acidosis [1913]/ Promotion of acid–base balance and prevention of complications resulting from serum PCO2 levels higher than desired

SAMPLE NIC ACTIVITIES ■ ■

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Monitor respiratory pattern Monitor ABG levels for decreasing pH level, as appropriate Monitor neurological status (e.g., level of consciousness and confusion) Monitor determinants of tissue oxygen delivery (e.g., PaO2, SaO2, hemoglobin levels) Provide mechanical ventilatory support if necessary

*

The NOC # for desired outcomes and the NIC # for nursing interventions are listed in brackets following the appropriate outcome or intervention. Outcomes, indicators, inter-

ventions, and activites selected are only a sample of those suggested by NOC and NIC and should be further individualized for each client.

(c) fluid intake modifications; (d) dietary changes; (e) parenteral fluid, electrolyte, and blood replacement; and (f) other appropriate measures such as administering prescribed medications and oxygen, providing skin care and oral hygiene, positioning the client appropriately, and scheduling rest periods.

Planning for Home Care To provide for continuity of care, the client’s needs for assistance with care in the home need to be considered. Home care planning includes assessment of the client’s and family’s resources and abilities for care, and the need for refer-

HOME CARE ASSESSMENT

Implementing Promoting Wellness Most people rarely think about their fluid, electrolyte, or acid–base balance. They know it is important to drink adequate

Fluid, Electrolyte, and Acid–Base Balance

CLIENT Risk factors for imbalances: The client’s age, medications required such as diuretic therapy or corticosteroids, and presence of chronic diseases such as diabetes mellitus, heart disease, lung disease, or dementia (see Box 52–3 on p. 1445) ■ Self-care abilities for maintaining food and fluid intake: Mobility; ability to chew and swallow, to access fluids and respond to thirst, to purchase food and prepare a balanced diet ■ Current level of knowledge (as appropriate) about: Prescribed diet, any fluid restrictions, activity restrictions, actions and side effects of prescribed medications, regular weight monitoring, gastric tube care and enteral feedings, central line or PICC catheter care, and parenteral fluids and nutrition ■

FAMILY ■

rals and home health services. The accompanying Home Care Assessment describes the specific assessment data required to establish a home care plan. Based on the data gathered in assessment of the home situation, the nurse tailors the teaching plan for the client and family (see Client Teaching on page 1453).

Caregiver availability, skills, and responses: Availability and willingness to assume responsibility for care, knowledge and ability to

provide assistance with preparing food and maintaining adequate intake of food and fluids, knowledge of risk factors and early warning signs of problems ■ Family role changes and coping: Effect on financial status, parenting and spousal roles, social roles ■ Alternate potential primary or respite caregivers: For example, other family members, volunteers, church members, paid caregivers or housekeeping services; available community respite care (e.g., adult day care, senior centers) COMMUNITY ■

Current knowledge of and experience with community resources: Home health agencies, organizations that offer financial assistance or assistance with food preparation, Meals on Wheels or meal services (e.g., at senior centers, homeless shelters), pharmacies, home intravenous services, respiratory care services

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CLIENT TEACHING

Promoting Fluid and Electrolyte Balance

Consume six to eight glasses of water daily. Avoid excess amounts of foods or fluids high in salt, sugar, and caffeine. ■ Eat a well-balanced diet. Include adequate amounts of milk or milk products to maintain bone calcium levels. ■ Limit alcohol intake because it has a diuretic effect. ■ Increase fluid intake before, during, and after strenuous exercise, particularly when the environmental temperature is high, and replace lost electrolytes from excessive perspiration as needed with commercial electrolyte solutions.

Maintain normal body weight. Learn about and monitor side effects of medications that affect fluid and electrolyte balance (e.g., diuretics) and ways to handle side effects. ■ Recognize possible risk factors for fluid and electrolyte imbalance such as prolonged or repeated vomiting, frequent watery stools, or inability to consume fluids because of illness. ■ Seek prompt professional health care for notable signs of fluid imbalance such as sudden weight gain or loss, decreased urine volume, swollen ankles, shortness of breath, dizziness, or confusion.

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fluids and consume a balanced diet, but they may not understand the potential effects when this is not done. Nurses can promote clients’ health by providing wellness teaching that will help them maintain fluid and electrolyte balance.

CLIENT TEACHING

Enteral Fluid and Electrolyte Replacement Fluids and electrolytes can be provided orally in the home and hospital if the client’s health permits, that is, if the client is not vomiting, has not experienced an excessive fluid loss, and has

Home Care and Fluid, Electrolyte, and Acid–Base Balance

MONITORING FLUID INTAKE AND OUTPUT Teach and provide the rationale for monitoring fluid intake and output to the client and family as appropriate. Include how to use a commode or collection device (“hat”) in the toilet, how to empty and measure urinary catheter drainage, and how to count or weigh diapers. ■ Instruct and provide the rationale for regular weight monitoring to the client and family. Weigh at the same time of day, using the same scale and with the client wearing the same amount of clothing. ■ Educate and provide the rationale to the client and family on when to contact a health care professional, such as in the cases of a significant change in urine output; any change of 5 pounds or more in a 1- to 2-week period; prolonged episodes of vomiting, diarrhea, or inability to eat or drink; dry, sticky mucous membranes; extreme thirst; swollen fingers, feet, ankles, or legs; difficulty breathing, shortness of breath, or rapid heartbeat; and changes in behavior or mental status.

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MAINTAINING FOOD AND FLUID INTAKE Instruct the client and family about any diet or fluid restrictions, such as a low-sodium diet. ■ Teach family members the rationale for the importance of offering fluids regularly to clients who are unable to meet their own needs because of age, impaired mobility or cognition, or other conditions such as impaired swallowing due to a stroke. ■ If the client is on enteral or intravenous fluids and feeding at home, teach and provide the underlying rationale to caregivers about proper administration and care. Contact a home health or home intravenous service to provide services and teaching.

MEDICATIONS Emphasize the importance of and rationale for taking medications as prescribed. ■ Instruct clients taking diuretics to take the medication in the morning. If a second daily dose is prescribed, they should take it in the late afternoon to avoid disrupting sleep to urinate. ■ Inform clients about any expected side effects of prescribed medications and how to handle them (e.g., if a potassium-depleting diuretic is prescribed, increase intake of potassium-rich foods; if taking a potassium-sparing diuretic, avoid excess potassium intake such as using a salt substitute). ■ Teach clients when to contact their primary care provider, for example, if they are unable to take a prescribed medication or have signs of an allergic or toxic reaction to a medication. ■

MEASURES SPECIFIC TO CLIENT’S PROBLEM ■

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SAFETY Instruct and provide the rationale to the client to change positions slowly if appropriate, especially when moving from a supine to a sitting or standing position. ■ Inform and provide the rationale to the client and family about the importance of good mouth and skin care. Teach the client to change positions frequently and to elevate the feet on a stool when sitting for a long period. ■

Teach the client and family how to care for intravenous access sites or gastric tubes. Include what to do if tubes become dislodged.

Provide instructions and rationale specific to the client’s fluid, electrolyte, or acid–base imbalance, such as a. Fluid volume deficit. b. Risk for fluid volume deficit. c. Fluid volume excess.

REFERRALS ■

Make appropriate referrals to home health or community social services for assistance with resources such as meals, meal preparation and food, intravenous infusions and access, enteral feedings, and homemaker or home health aide services to help with ADLs.

COMMUNITY AGENCIES AND OTHER SOURCES OF HELP Provide information about companies or agencies that can provide durable medical equipment such as commodes, lift chairs, or hospital beds for purchase, for rental, or free of charge. ■ Provide a list of sources for supplies such as catheters and drainage bags, measuring devices, tube feeding formulas, and electrolyte replacement drinks. ■ Suggest additional sources of information and help such as the American Dietetic Association, the American Heart Association, and the American Lung Association. ■

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PRACTICE GUIDELINES ■

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Facilitating Fluid Intake

Explain to the client the reason for the required intake and the specific amount needed. This provides a rationale for the requirement and promotes compliance. Establish a 24-hour plan for ingesting the fluids. For the hospitalized or long-term care client, half of the total volume is given during the day shift, and the other half is divided between the evening and night shifts, with most of that ingested during the evening shift. For example, if 2,500 mL is to be ingested in 24 hours, the plan may specify 7–3 (1,500 mL); 3–11 (700 mL); and 11–7 (300 mL). Try to avoid the ingestion of large amounts of fluid immediately before bedtime to prevent the need to urinate during sleeping hours. Set short-term outcomes that the client can realistically meet. Examples include ingesting a glass of fluid every hour while awake or a pitcher of water by 12 noon. Identify fluids the client likes and make available a variety of those items, including fruit juices, soft drinks, and milk (if al-

an intact gastrointestinal tract and gag and swallow reflexes. Clients who are unable to ingest solid foods may be able to ingest fluids. FLUID INTAKE MODIFICATIONS. Increased fluids (ordered as “push fluids”) are often prescribed for clients with actual or potential fluid volume deficits arising, for example, from mild diarrhea or mild to moderate fevers. Guidelines for helping clients increase fluid intake are shown in the above Practice Guidelines. Restricted fluids may be necessary for clients who have fluid retention (fluid volume excess) as a result of renal failure, congestive heart failure, SIADH, or other disease processes. Fluid restrictions vary from “nothing by mouth” to a precise amount ordered by a primary care provider. The restriction of fluids can be difficult for some clients, particularly if they are experiencing thirst. Guidelines for helping clients restrict fluid intake are shown in Practice Guidelines.

PRACTICE GUIDELINES ■

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lowed). Remember that beverages such as coffee and tea have a diuretic effect, so their consumption should be limited. Help clients to select foods that tend to become liquid at room temperature (e.g., gelatin, ice cream, sherbet, custard), if these are allowed. For clients who are confined to bed, supply appropriate cups, glasses, and straws to facilitate appropriate fluid intake and keep the fluids within easy reach. Make sure fluids are served at the appropriate temperature: hot fluids hot and cold fluids very cold. Encourage clients when possible to participate in maintaining the fluid intake record. This assists them to evaluate the achievement of desired outcomes. Be alert to any cultural implications of food and fluids. Some cultures may restrict certain foods and fluids and view others as having healing properties.

DIETARY CHANGES. Specific fluid and electrolyte imbal-

ances may require simple dietary changes. For example, clients receiving potassium-depleting diuretics need to be informed about foods with a high potassium content (e.g., bananas, oranges, and leafy greens). Some clients with fluid retention need to avoid foods high in sodium. Most healthy clients can benefit from foods rich in calcium. ORAL ELECTROLYTE SUPPLEMENTS. Some clients can benefit from oral supplements of electrolytes, particularly when a medication is prescribed that affects electrolyte balance, when dietary intake is inadequate for a specific electrolyte, or when fluid and electrolyte losses are excessive as a result of, for example, excessive perspiration. Corticosteroids and many diuretics can cause too much potassium to be eliminated through the kidneys. For clients taking these medications, potassium supplements may be prescribed. Instruct clients taking oral potassium supplements to

Helping Clients Restrict Fluid Intake

Explain the reason for the restricted intake and how much and what types of fluids are permitted orally. Many clients need to be informed that ice chips, gelatin, and ice cream, for example, are considered fluid. Help the client decide the amount of fluid to be taken with each meal, between meals, before bedtime, and with medications. For the hospitalized or long-term care client, half the total volume is scheduled during the day shift, when the client is most active, receives two meals, and most oral medications. A large part of the remainder is scheduled for the evening shift to permit fluids with meals and evening visitors. Identify fluids or fluidlike substances the client likes and make sure that these are provided, unless contraindicated. A client who is allowed only 200 mL of fluid for breakfast, for example, should receive the type of fluid the client favors. Set short-term goals that make the fluid restriction more tolerable. For example, schedule a specified amount of fluid at one

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or two hourly intervals between meals. Some clients may prefer fluids only between meals if the food provided at mealtime helps relieve thirst. Place allowed fluids in small containers such as a 4-ounce juice glass to allow the perception of a full container. Periodically offer the client ice chips as an alternative to water, because ice chips when melted are approximately half of the frozen volume. Provide frequent mouth care and rinses to reduce the thirst sensation. Instruct the client to avoid ingesting or chewing salty or sweet foods (hard candy or gum), because these foods tend to produce thirst. Sugarless gum may be an alternative for some clients. Encourage the client when possible to participate in maintaining the fluid intake record.

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take the medication with juice to mask the unpleasant taste and reduce the possibility of gastric distress. Emphasize the importance of taking the medication as prescribed and seeing their primary care provider on a regular basis. Because hyperkalemia can have serious cardiac effects, clients should never increase the amount of potassium being taken without an order to do so. In addition, inform clients that most salt substitutes contain potassium, so it is important to consult with the primary care provider before using salt substitutes. People who ingest insufficient milk and milk products benefit from calcium supplements. The recommended daily allowance for calcium is 1,000 to 1,500 mg. It is generally recommended that postmenopausal women take 1,500 mg of calcium per day to reduce the risk of osteoporosis. Long-term use of corticosteroid drugs can also cause calcium loss from the bone, and calcium supplements may help reduce this loss. Clients who take supplemental calcium need to maintain a fluid intake of at least 2,500 mL per day (unless contraindicated) to reduce the risk of kidney stones, which are commonly composed of calcium salts. Although routine supplements for other electrolytes generally are not recommended, clients who have poor dietary habits, who are malnourished, or who have difficulty accessing or eating fresh fruits and vegetables may benefit from electrolyte supplements. A daily multiple vitamin with minerals may achieve the desired goal. People who engage in strenuous activity in a warm environment need to be encouraged to replace water and electrolytes lost through excessive perspiration by consuming a sports drink such as Gatorade or another commercial fluid and electrolyte solution. Liquid nutritional supplements are often given to clients who are malnourished or have poor eating habits. They are used with frequency in older adults to bolster nutritional status and caloric intake. It is very important to be a “label reader” of the product and to be aware of the contents of the supplement. Some of them are very high in protein and high in potassium, which may be contraindicated in an individual with impaired renal function.

TABLE 52–10

Parenteral Fluid and Electrolyte Replacement Intravenous (IV) fluid therapy is essential when clients are unable to take food and fluids orally. It is an efficient and effective method of supplying fluids directly into the intravascular fluid compartment and replacing electrolyte losses. Intravenous fluid therapy is usually ordered by the primary care provider. The nurse is responsible for administering and maintaining the therapy and for teaching the client and significant others how to continue the therapy at home if necessary. INTRAVENOUS SOLUTIONS. Intravenous solutions can be classified as isotonic, hypotonic, or hypertonic. Most IV solutions are isotonic, having the same concentration of solutes as blood plasma. Isotonic solutions are often used to restore vascular volume. Hypertonic solutions have a greater concentration of solutes than plasma; hypotonic solutions have a lesser concentration of solutes. Table 52–10 provides examples of IV solutions and nursing implications. IV solutions can also be categorized according to their purpose. Nutrient solutions contain some form of carbohydrate (e.g., dextrose, glucose, or levulose) and water. Water is supplied for fluid requirements and carbohydrate for calories and energy. For example, 1 L of 5% dextrose provides 170 calories. Nutrient solutions are useful in preventing dehydration and ketosis but do not provide sufficient calories to promote wound healing, weight gain, or normal growth in children. Common nutrient solutions are 5% dextrose in water (D5W) and 5% dextrose in 0.45% sodium chloride (dextrose in half-strength saline). Electrolyte solutions contain varying amounts of cations and anions. Commonly used solutions are normal saline (0.9% sodium chloride solution), Ringer’s solution (which contains sodium, chloride, potassium, and calcium), and lactated Ringer’s solution (which contains sodium, chloride, potassium, calcium, and lactate). Lactate is metabolized in the liver to form bicarbonate HCO3⫺. Saline and balanced electrolyte solutions commonly are used to restore vascular volume, particularly

Selected Intravenous Solutions

TYPE/EXAMPLES

COMMENTS/NURSING IMPLICATIONS

Isotonic Solutions 0.9% NaCl (normal saline) Lactated Ringer’s (a balanced electrolyte solution) 5% dextrose in water (D5W)

Isotonic solutions such as NS and lactated Ringer’s initially remain in the vascular compartment, expanding vascular volume. Assess clients carefully for signs of hypervolemia such as bounding pulse and shortness of breath. D5W is isotonic on initial administration but provides free water when dextrose is metabolized, expanding intracellular and extracellular fluid volumes. D5W is avoided in clients at risk for increased intracranial pressure (IICP) because it can increase cerebral edema.

Hypotonic Solutions 0.45% NaCl (half normal saline) 0.33% NaCl (one-third normal saline) Hypertonic Solutions 5% dextrose in normal saline (D5NS) 5% dextrose in 0.45% NaCl (D5 1/2NS) 5% dextrose in lactated Ringer’s (D5LR)

Hypotonic solutions are used to provide free water and treat cellular dehydration. These solutions promote waste elimination by the kidneys. Do not administer to clients at risk for IICP or third-space fluid shift. Hypertonic solutions draw fluid out of the intracellular and interstitial compartments into the vascular compartment, expanding vascular volume. Do not administer to clients with kidney or heart disease or clients who are dehydrated. Watch for signs of hypervolemia.

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after trauma or surgery. They also may be used to replace fluid and electrolytes for clients with continuing losses, for example, because of gastric suction or wound drainage. Lactated Ringer’s solution is an alkalinizing solution that may be given to treat metabolic acidosis. Acidifying solutions, in contrast, are administered to counteract metabolic alkalosis. Examples of acidifying solutions are 5% dextrose in 0.45% sodium chloride and 0.9% sodium chloride solution. Volume expanders are used to increase the blood volume following severe loss of blood (e.g., from hemorrhage) or loss of plasma (e.g., from severe burns, which draw large amounts of plasma from the bloodstream to the burn site). Examples of expanders are dextran, plasma, and albumin.

Cephalic vein

Insertion site for PICC

PRACTICE GUIDELINES ■ ■ ■

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Vein Selection

Use distal veins of the arm first. Use the client’s nondominant arm whenever possible. Select a vein that is a. Easily palpated and feels soft and full. b. Naturally splinted by bone. c. Large enough to allow adequate circulation around the catheter. Avoid using veins that are a. In areas of flexion (e.g., the antecubital fossa). b. Highly visible, because they tend to roll away from the needle. c. Damaged by previous use, phlebitis, infiltration, or sclerosis. d. Continually distended with blood, or knotted or tortuous. e. In a surgically compromised or injured extremity (e.g., following a mastectomy), because of possible impaired circulation and discomfort for the client.

Accessory cephalic vein

Basilic vein

Cephalic vein

Medial antebrachial vein

VENIPUNCTURE SITES. The site chosen for venipuncture

varies with the client’s age, the length of time the infusion is to run, the type of solution used, and the condition of veins. For adults, veins in the hand and arm are commonly used; for infants, veins in the scalp and dorsal foot veins are often used. Larger veins are preferred for infusions that need to be given rapidly and for solutions that could be irritating (e.g., certain medications). The metacarpal, basilic, and cephalic veins are commonly used for intermittent or continuous infusions (Figure 52-16 ■, B). The ulna and radius act as natural splints at these sites, and the client has greater freedom of arm movements for activities such as eating. Although the basilic and median cubital veins in the antecubital space are convenient sites for venipuncture, they are usually used for blood draws, bolus injections of medication, and insertion sites for a peripherally inserted central catheter line (see Figure 52-16 ■, A). See Practice Guidelines for vein selection and general tips for easier IV starts. When long-term IV therapy or parenteral nutrition is anticipated or the client is receiving IV medications that are damaging to vessels (e.g., chemotherapy), a central venous catheter may be inserted. Central venous catheters usually are inserted into the subclavian or jugular vein, with the distal tip of the catheter resting in the superior vena cava just above the right

Median cubital vein

Basilic vein

A

B

Radial vein

Basilic vein Cephalic vein Dorsal venous network Dorsal metacarpal veins

Figure 52-16 ■ Commonly used venipuncture sites of the A, arm; B, hand. A also shows the site used for a peripherally inserted central catheter (PICC).

atrium (Figure 52-17 ■). They may be inserted at the client’s bedside or, for longer term access, surgically inserted. Subclavian central venous catheters permit freedom of movement for ambulation; however, there is greater risk of complications, including hemothorax or pneumothorax, cardiac perforation, thrombosis, and infection. Assess the client closely for manifestations such as shortness of breath, chest pain, cough, hypotension, tachycardia, and anxiety after the insertion procedure. With a peripherally inserted central venous catheter (PICC), the catheter is inserted in the basilic or cephalic vein just above or below the antecubital space of the right arm. The tip of the catheter rests in the superior vena cava. The risk of pneumothorax is eliminated with PICC. These catheters frequently are used for long-term intravenous access when the client will be managing IV therapy at home. Implantable venous access devices or ports (Figures 52-18 ■ and 52-19 ■ on page 1458) are used for clients with chronic illness who require long-term IV therapy (e.g., intermittent medications such as chemotherapy, total parenteral nutrition, and

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PRACTICE GUIDELINES ■

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General Tips for Easier IV Starts

Review the client’s medical history. In general, you’ll want to avoid using an arm affected by hemiplegia or with a dialysis access. Also avoid an arm on the same side as a mastectomy, sites near infections or below previous infiltrations of extravasations, and veins affected by phlebitis. Put gravity to work. Dangle the client’s arm over the side of the bed to encourage dependent vein filling. Make sure the client is comfortable. Pain and anxiety stimulate the sympathetic nervous system and trigger vasoconstriction and vasovagal reactions. Have the client void before you start the IV line, make sure he or she is warm enough, and administer pain medication as ordered before the procedure. Help the patient into a comfortable prone or semi-Fowler position for the IV insertion. Warmth encourages vasodilation. Apply warm compresses to the site for 10 to 15 minutes before you attempt venipuncture. Unless contraindicated, the client could take a hot shower or drink warm fluids before IV insertion. Avoid hand veins. Because of the risk of nerve injuries, hand veins should be a last choice, especially in older clients whose skin is very thin. Choose the right device for the ordered therapy. If the ordered IV medication is irritating to veins and therapy is expected to last more than a few days, consult with the IV nurse or medical team to determine whether the client is a candidate for a mid-

frequent blood samples). The device is designed to provide repeated access to the central venous system, avoiding the trauma and complications of multiple venipunctures. Using local anesthesia, implantable ports are surgically placed into a small sub-

Catheter Subclavian vein

Superior vena cava

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line catheter, a peripherally inserted central catheter, or another type of central venous access device. Use the smallest gauge cannula that will accommodate the therapy and allow good venous flow around the catheter tip. For example, for routine hydration or intermittent therapies, use 22- to 27-gauge catheters; for transfusion therapies, 20- to 24-gauge; and for therapy for neonates or clients with very small, fragile veins, 24- to 27-gauge. Use good body mechanics. Raise the bed or stretcher to a comfortable working height. Sit, when possible, and keep all equipment within reach. Stabilize the client’s hand or arm with your nondominant arm, tucking it under your forearm if necessary to prevent a moving target. Display confidence in your own abilities. When you approach the client, don’t say, “I’m here to try to start your IV line.” Instead, confidently state, “I’m here to insert your IV line.” If you miss, offer an honest explanation in a matter-of-fact and friendly manner. Think about what you can do to improve your next attempt, and explain what you’ll do differently (if anything). Most important, limit your attempts to two. If you’re not successful after two tries, ask another nurse or an anesthesia provider to try again a little later.

Note: From “Tailor Your I.V. Insertion Techniques for Special Populations,” by K. Rosenthal, 2005a, Nursing, 35(5), 39. Copyright © 2005 Lippincott, Williams & Wilkins. Reprinted with permission.

cutaneous pocket under the skin, usually on the anterior chest near the clavicle, and no part of the port is exposed. The distal end of the catheter is placed in the subclavian or jugular vein. There are different kinds of implantable venous access devices and they may be tunneled or nontunneled (Rosenthal, 2005b). Special precautions need to be taken with all central lines and venous access ports to ensure asepsis and catheter patency. Nursing care of clients with these devices is outlined in Practice Guidelines on page 1459. INTRAVENOUS EQUIPMENT. Because equipment varies ac-

A Catheter Internal jugular vein Subclavian vein Superior vena cava

B

Figure 52-17 ■ Central venous lines with A, subclavian vein insertion, and B, left jugular insertion.

cording to the manufacturer, the nurse must become familiar with the equipment used in each particular agency. Solution containers are available in various sizes (50, 100, 250, 500, or 1,000 mL); the smaller containers are often used to administer medications. Most solutions are currently dispensed in plastic bags (Figure 52-20 ■). However, glass bottles may need to be used if the administered medications are incompatible with plastic. Glass bottles require an air vent so that air can enter the bottle and replace the fluid that enters the client’s vein. Some have a tube inside the bottle that serves as a vent; other containers without air vents require a vent on the administration set. Air vents usually have filters to prevent contamination from the air that enters the container. Air vents are not required for plastic solution bags, because the bags collapse under atmospheric pressure when the solution enters the vein. It is essential that the solution be sterile and in good condition, that is, clear. Cloudiness, evidence that the container has been opened previously, or leaks indicate possible contamination. Always check the expiration date on the label. Return any

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Catheter Lock

Self-sealing septum

A

Skin

Figure 52-20 ■ A plastic intravenous fluid container.

Catheter Suture Fluid flow B

container when the equipment is set up and ready to start. The drip chamber permits a predictable amount of fluid to be delivered. A commonly used drip chamber is the 10 to 20 drops, which delivers macrodrip per milliliter of solution. This infor-

Figure 52-18 ■ An implantable venous access device: A, components; B, the device in place.

Protector cap for insertion spike

questionable or contaminated solutions to the pharmacy or IV therapy department. Infusion sets usually include an insertion spike, a drip chamber, a roller valve or screw clamp, tubing with secondary ports, and a protective cap over the needle adapter (Figure 52-21 ■). The insertion spike is kept sterile and inserted into the solution

Spike connector for fluid container Connector to IV catheter Drip chamber

Secondary port

Clamp Secondary port Clamp

Figure 52-19 ■ An implantable venous access device (right) and a Huber needle with extension tubing.

Figure 52-21 ■ A standard IV administration set.

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PRACTICE GUIDELINES ■

Caring for Clients with a Venous Access Device

On insertion, document the date; the site; the brand, gauge, and catheter length; the location of the catheter tip (verified by x-ray); the length of the external segment; and client teaching. Do not use the access device until correct placement has been verified by x-ray.

SITE CARE ■ Use strict aseptic technique when caring for central lines and long-term venous access devices. ■ The frequency of dressing changes may vary from every 3 to 7 days, depending on the site. Dressings also should be changed when loose or soiled. ■ Assess the site for any redness, swelling, tenderness, or drainage. Compare the length of the external portion of the catheter with its documented length to assess for possible displacement. Obtain a chest x-ray to determine the catheter tip’s position if in doubt. Report and document any position changes or signs of infection. ■ Follow agency protocol for cleaning solutions and types of dressings. Isopropyl alcohol or a combination of alcohol and acetone followed by povidone-iodine are commonly used to clean the port site. ■ Before accessing the port, clean an area 2 inches in diameter around the site with an alcohol-acetone solution on a sterile cotton swab. Start at the center of the port site, moving outward with a firm, circular motion. Follow with povidone-iodine solution. Allow the site to air dry. ■ Secure the catheter, and cover the entry site and external portion of the catheter with an occlusive dressing. ■ Provide routine care of the incision site for the implant device until it is healed. Once it heals, no care is necessary when the port is idle. CATHETER CARE AND FLUSHING Change the catheter cap as indicated by protocol, usually every 3 to 7 days. ■ Flush the port with normal saline, a heparin flush solution (10 units/mL or 100 units/mL), or as agency protocol recommends for the specific type of port being used. After infusing medications or solutions, again flush the port with saline before using heparinized saline. ■

mation is found on the package. There are also 60 drops sets, which deliver microdrip per milliliter of solution. The roller valve or screw clamp, which compresses the lumen of the tubing, controls the rate of the flow. The protective cap over the needle adapter maintains the sterility of the end of the tubing so that it can be attached to a sterile needle inserted in the client’s vein. Most infusion sets include one or more injection ports for administering IV medications or secondary infusions. Needleless systems are increasingly used because they reduce the risk of needlestick injury and contamination of the intravenous line. There are various types of needleless systems available, including two-piece prepierced septum and blunt cannula devices, Luer-activated devices, and three-way pressure-activated safety valves (Rosenthal, 2003). With each of these needleless systems, a blunt cannula is inserted into a special injection port or adapter on the IV tubing to administer medications or secondary infusions (Figure 52-22 ■). Many infusion sets include an

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Using a 10-mL syringe, flush the catheter with a solution of 10 units of heparin after each use. The frequency of flushes between uses may vary from every 12 hours to once a week or less, depending on the type of catheter. Remember to flush all lumens for multiple-lumen catheters. Use a specially designed needle to access an implanted port. A needle with a 90-degree angle is generally used for infusions because it is easier to stabilize and more comfortable for the client. Stabilizing the port between the thumb and index finger of the nondominant hand, insert the needle through the center of the port until the resistance of the platform is felt. To remove the needle after a treatment, again stabilize the port and use even pressure to withdraw the needle. Maintain positive pressure by withdrawing the needle as the last milliliter of flush solution is being instilled. Flush idle implanted ports with heparinized saline in accordance with agency protocol or at least every 8 weeks.

TEACHING Provide clients with the following instructions: ■ ■ ■

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Do not allow anyone to take a blood pressure on the arm in which a PICC line is inserted. Wear a medic-alert tag or bracelet if the device is to be in place for a long period. For a PICC, you do not need to restrict activities, except do not immerse the arm in water. Showering is allowed if the site and catheter are covered by an occlusive dressing. For an implanted venous port there are no activity restrictions, but remember that the port or catheter tip can become dislodged. Signs of a dislodged catheter tip include pain in the neck or ear on the affected side, swishing or gurgling sounds, or palpitations. Free movement of the port, swelling, or difficulty accessing the port may indicate port dislodgment. Notify the primary care provider should any of these occur or if symptoms of infection develop.

Note: From “Getting a Line on Central Vascular Access Devices,” by S. Masoorli & T. Angeles, 2002, Nursing, 32(4), pp. 36–43. Copyright © 2005 Lippincott, Williams & Wilkins. Reprinted with permission.

in-line filter to trap air, particulate matter, and microbes. A special infusion set may be required if the IV flow rate will be regulated by an infusion pump. Catheters and needles are commonly used for intravenous infusions. Over-the-needle catheters, also known as angiocaths, are commonly used for adult clients. The plastic catheter fits over a needle used to pierce the skin and vein wall (Figure 52-23 ■). Once inserted into the vein, the needle is withdrawn and discarded, leaving the catheter in place. IV catheters allow the client more mobility and rarely infiltrate, that is, become dislodged from the vein and allow fluid to flow into interstitial spaces. Safety devices on IV catheters are now common. With the original over-the-needle catheters, the sharp stylet remained exposed until placed in a sharps container. This resulted in needlestick injuries to nurses. The 2000 Needlestick Safety and Prevention Act requires the use of needle saftey devices to prevent exposure to

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A

B

Figure 52-22 ■ Cannulae used to connect the tubing of additive sets to primary infusions: A, threaded-lock cannula; B, lever-lock cannula. (Photographs reprinted courtesy of (BD) Becton, Dickinson and Company and courtesy of Baxter Healthcare Corporation. All rights reserved.)

Introducer needle

MediaLink

Applying a Central Venous Line Animation

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Tapered catheter tip

Short bevel introducer needle

Preview chamber

Translucent catheter hub

Cannula

Luer lock tabs

Finger guard

Flashback chamber

Filter vent

Needle bevel position indicator

Needle heel

Figure 52-23 ■ Schematic of an over-the-needle catheter.

bloodborne pathogens (Wilburn, 2004). The safety devices for IV catheters vary. They can be either an active safety device which requires activation by the nurse or a passive safety device where the safety feature is automatically activated after the sytlet is removed from the catheter. Butterfly, or wing-tipped, needles with plastic flaps attached to the shaft are sometimes used (Figure 52-24 ■). The flaps are held tightly together to hold the needle securely during insertion; after insertion, they are flattened against the skin and secured with tape. IV poles are used to hang the solution container. Some poles are attached to hospital beds; others stand on the floor

Cap for needle Stem Plastic adapter Wings

or hang from the ceiling. In the home, plant hangers or robe hooks (even kitchen cabinet knobs or an S-hook over the top of a door) may be used to hang solution containers. The height of most poles is adjustable. The higher the solution container, the greater the force of the solution as it enters the client and the faster the rate of flow. STARTING AN INTRAVENOUS INFUSION. Although the primary care provider is responsible for ordering IV therapy for clients, nurses initiate, monitor, and maintain the prescribed IV infusion. This is true not only in hospitals and long-term care facilities but increasingly in community-based settings such as clinics and clients’ homes. Before starting an infusion, the nurse determines the following: ■ ■ ■

Tubing

Figure 52-24 ■ Schematic of a butterfly needle with adapter.

The type and amount of solution to be infused The exact amount (dose) of any medications to be added to a compatible solution The rate of flow or the time over which the infusion is to be completed

If solutions are prepared by the pharmacy or another department, the nurse must verify that the solution supplied exactly matches that which the primary care provider ordered. Understanding the purpose for the infusion is as important as assessing the client. For example, the nurse may question an order for 5% dextrose in water at 150 mL/h if the client has peripheral edema and other signs of fluid overload. To perform venipuncture and start an intravenous infusion, see Skill 52-1.

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STARTING AN INTRAVENOUS INFUSION be administered, the rate of flow of the infusion, and any client allergies (e.g., to tape or povidone-iodine).

PURPOSES ■ To supply fluid when clients are unable to take in an adequate volume of fluids by mouth ■ To provide salts and other electrolytes needed to maintain electrolyte balance

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ASSESSMENT Assess the following:

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Vital signs (pulse, respiratory rate, and blood pressure) for baseline data ■ Skin turgor ■

PLANNING Prior to initiating the IV infusion, consider how long the client is likely to have the IV, what kinds of fluids will be infused, and what medications the client will be receiving or is likely to receive. These factors may affect the choice of vein and catheter size. Delegation This procedure is done by a registered nurse and, in many states, by a licensed pratical nurse or licensed vocational nurse. Check the state’s nurse practice act. Due to the use of sterile technique, intravenous infusion therapy is not delegated to unlicensed assistive personnel (UAP). UAP may care for clients receiving IV therapy, and the nurse must ensure that the UAP knows how to perform routine tasks such as bathing and positioning without disturbing the IV. The UAP should also know what complications or adverse signs, such as leakage, should be reported to the nurse. In some states a licensed vocational nurse with special IV therapy training may start intravenous infusions.

IMPLEMENTATION Preparation 1. Prepare the client. ● Prior to performing the procedure, introduce self and verify the client’s identity using agency protocol. Explain the procedure to the client. A venipuncture can cause discomfort for a few seconds, but there should be no discomfort while the solution is flowing. Use a doll to demonstrate for children, and explain the procedure to the parents. Clients often want to know how long the process will last. The primary care provider’s order may specify the length of time of the infusion, for example, 3,000 mL over 24 hours. ● Unless initiating IV therapy is urgent, provide any scheduled care before establishing the infusion to minimize movement of the affected limb during the procedure. Moving the limb after the infusion has been established could dislodge the catheter. ● Make sure that the client’s clothing or gown can be removed over the IV apparatus if necessary. Some agencies provide special gowns that open over the shoulder and down the sleeve for easy removal.

To provide glucose (dextrose), the main fuel for metabolism To provide water-soluble vitamins and medications ■ To establish a lifeline for rapidly needed medications ■

Allergy to latex (e.g., tourniquet), tape, or iodine Bleeding tendencies ■ Disease or injury to extremities ■ Status of veins to determine appropriate venipuncture site ■

Equipment ■ Infusion set ■ Sterile parenteral solution ■ IV pole ■ Adhesive or nonallergenic tape ■ Clean gloves ■ Tourniquet ■ Antiseptic swabs ■ Antiseptic ointment (check agency policy) ■ Intravenous catheter; see Variation at the end of this procedure for a butterfly (winged-tip) needle ■ Sterile gauze dressing or transparent occlusive dressing ■ Arm splint, if required ■ Towel or pad ■ Electronic infusion device or pump (The nurse decides what device is needed as appropriate to the client’s condition.)

Performance Perform hand hygiene. 1. Open and prepare the infusion set. ● Remove tubing from the container and straighten it out. ● Slide the tubing clamp along the tubing until it is just below the drip chamber to facilitate its access. ● Close the clamp. ● Leave the ends of the tubing covered with the plastic caps until the infusion is started. Rationale: This will maintain the sterility of the ends of the tubing. 2. Spike the solution container. ● Remove the protective cover from the entry site of the bag. ● Remove the cap from the spike and insert the spike into the insertion site of the bag or bottle.
Follow the manufacturer’s instructions. 3. Apply a medication label to the solution container if a medication is added. ● In many agencies, medications and labels are applied in the pharmacy; if they are not, apply the label upside down on the container. Rationale: The label is applied upside down so it can be read easily when the container is hanging up. continued on page 1462

SKILL 52-1

Before preparing the infusion, the nurse first verifies the primary care provider’s order indicating the type of solution, the amount to

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STARTING AN INTRAVENOUS INFUSION continued


Inserting the spike. Photographer: Elena Dorfman

4. Apply a timing label on the solution container. ● The timing label may be applied at the time the infusion is started. Follow agency practice. See later discussion of regulating infusion flow rates and Figure 52-26. 5. Hang the solution container on the pole. ● Adjust the pole so that the container is suspended about 1 m (3 ft) above the client’s head. Rationale: This height is needed to enable gravity to overcome venous pressure and facilitate flow of the solution into the vein. 6. Partially fill the drip chamber with solution. ● Squeeze the chamber gently until it is half full of solution.  7. Prime the tubing. ● Remove the protective cap and hold the tubing over a container. Maintain the sterility of the end of the tubing and the cap. ● Release the clamp and let the fluid run through the tubing until all bubbles are removed. Tap the tubing if necessary with your fingers to help the bubbles move. Rationale: The tubing is primed to prevent the introduction of air into the client.

Air bubbles smaller than 0.5 mL usually do not cause problems in peripheral lines. ● Reclamp the tubing and replace the tubing cap, maintaining sterile technique. ● For caps with air vents, do not remove the cap when priming this tubing. The flow of solution through the tubing will cease when the cap is moist with one drop of solution. ● If an infusion control pump, electronic device, or controller is being used, follow the manufacturer’s directions for inserting the tubing and setting the infusion rate. 8. Perform hand hygiene again just prior to client contact. 9. Select the venipuncture site. ● Use the client’s nondominant arm, unless contraindicated (e.g., mastectomy, fistula for dialysis). Identify possible venipuncture sites by looking for veins that are relatively straight, not sclerotic or tortuous, and avoid venous valves. The vein should be palpable, but may not be visible, especially in clients with dark skin. Consider the catheter length; look for a site sufficiently distal to the wrist or elbow that the tip of the catheter will not be at a point of flexion. Rationale: Sclerotic veins may make initiating and maintaining the IV difficult. Joint flexion increases the risk of irritation of vein walls by the catheter. ● Check agency protocol about shaving if the site is very hairy. Shaving is not usually recommended because of the potential for microabrasions which can increase the risk of infection. ● Place a towel or bed protector under the extremity to protect linens (or furniture if in the home). 10. Dilate the vein. ● Place the extremity in a dependent position (lower than the client’s heart). Rationale: Gravity slows venous return and distends the veins. Distending the veins makes it easier to insert the needle properly. ● Apply a tourniquet firmly 15 to 20 cm (6 to 8 in.) above the venipuncture site.  Explain that the tourniquet will feel tight. Rationale: The tourniquet must be tight enough to obstruct venous flow but not so tight that it occludes arterial flow. Obstructing arterial flow inhibits venous filling. If a radial pulse can be palpated, the arterial flow is not obstructed. Use the tourniquet on only one client. This avoids crosscontamination to other clients. Pull this end to untie

A

B

 Squeezing the drip chamber. Photographer: Elena Dorfman

 Applying a tourniquet.

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 Taping an intravenous catheter by the “U” method.

Holding the over-the-needle catheter at a 15- to 30-degree angle with bevel up, insert the catheter through the skin and into the vein. Sudden lack of resistance is felt as the needle enters the vein. Jabbing, stabbing, or quick thrusting should be avoided because it may cause rupture of delicate veins (Phillips, 2005). ● Once blood appears in the lumen of the needle or you feel the lack of resistance, lower the angle of the catheter until it is almost parallel with the skin, and advance the needle and catheter approximately 0.5 to 1 cm (about 1/4 in.) farther. Holding the needle portion steady, advance the catheter until the hub is at the venipuncture site. The exact technique depends on the type of device used. Rationale: The catheter is advanced to ensure that it, and not just the metal needle, is in the vein. The exact technique depends on the type of catheter used. ● Release the tourniquet. ● Put pressure on the vein proximal to the catheter to eliminate or reduce blood oozing out of the catheter. Stabilize the hub with thumb and index finger of the nondominant hand. ● Remove the protective cap from the distal end of the tubing and hold it ready to attach to the catheter, maintaining the sterility of the end. ● Carefully remove the needle, engage the needle safety device, and attach the end of the infusion tubing to the catheter hub. ● Initiate the infusion. 13. Tape the catheter. ● Tape the catheter by the “U” method or according to the manufacturer’s instructions. Using three strips of adhesive tape, each about 7.5 cm (3 in.) long: a. Place one strip, sticky side up, under the catheter’s hub. b. Fold each end over so that the sticky sides are against the skin.  c. Place the second strip, sticky side down, over the catheter hub. d. Place the third strip, sticky side down, over the tubing hub. 14. Dress and label the venipuncture site and tubing according to agency policy. ● Unless there is an allergy, a sterile transparent occlusive dressing is applied.  This permits assessment of the site ●

 Cover insertion site with transparent dressing. (Patrick Watson)

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SKILL 52-1

If the vein is not sufficiently dilated: a. Massage or stroke the vein distal to the site and in the direction of venous flow toward the heart. Rationale: This action helps fill the vein. b. Encourage the client to clench and unclench the fist. Rationale: Contracting the muscles compresses the distal veins, forcing blood along the veins and distending them. c. Lightly tap the vein with your fingertips. Rationale: Tapping may distend the vein. ● If the preceding steps fail to distend the vein so that it is palpable, remove the tourniquet and wrap the extremity in a warm, moist towel for 10 to 15 minutes. Rationale: Heat dilates superficial blood vessels, causing them to fill. Then repeat step 10. 11. Put on clean gloves and clean the venipuncture site. Rationale: Gloves protect the nurse from contamination by the client’s blood. ● Clean the skin at the site of entry with a topical antiseptic swab (e.g., 2% chlorhexidine, or alcohol). Some institutions may use an anti-infective solution such as povidone-iodine (check agency protocol). Check for allergies to iodine or shellfish before cleansing skin with Betadine or iodine products. ● Use a circular motion, moving from the center outward for several inches. Rationale: This motion carries microorganisms away from the site of entry. ● Permit the solution to dry on the skin. Povidone-iodine should be in contact with the skin for 1 minute to be effective. 12. Insert the catheter and initiate the infusion. ● If desired and permitted by policy, inject 0.05 mL of 1% lidocaine intradermally over the site where you plan to insert the IV needle. Allow 5 to 10 seconds for the anesthetic to take effect. Transdermal analgesic creams (e.g., ELA-Max, EMLA) may also be used, depending on policy. Allow 30 minutes for the transdermal analgesic to take effect. ● Use the nondominant hand to pull the skin taut below the entry site. Rationale: This stabilizes the vein and makes the skin taut for needle entry. It can also make initial tissue penetration less painful. ●

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SKILL 52-1

that it is changed at regular intervals (i.e., every 24 to 96 hours according to agency policy). 17. Document relevant data, including assessments. ● Record the start of the infusion on the client’s chart. Some agencies provide a special form for this purpose. Include the date and time of the venipuncture; amount and type of solution used, including any additives (e.g., kind and amount of medications); container number; flow rate; type, length, and gauge of the needle or catheter; venipuncture site, how many attempts were made, and location of each attempt; the type of dressing applied; and the client’s general response. SAMPLE DOCUMENTATION

 Label IV site with date, time, size of catheter, and initials. (Patrick Watson)

without disturbing the dressing. This type of dressing can be left on for 72 hours, then changed. ● Discard the tourniquet. Remove soiled gloves and discard appropriately. ● Loop the tubing and secure it with tape. Rationale: Looping and securing the tubing prevent the weight of the tubing or any movement from pulling on the needle or catheter. ● Label the dressing with the date and time of insertion, type, gauge of catheter used, and your initials.  15. Ensure appropriate infusion flow. ● Apply a padded arm board to splint the joint, as needed. ● Adjust the infusion rate of flow according to the order. 16. Label the IV tubing. ● Label the tubing with the date and time of attachment and your initials.  This labeling may also be done when the infusion is started. Rationale: The tubing is labeled to ensure

1/15/2008 0600 Inserted 20 gauge angiocath in (L) forearm on first attempt. IV infusing at 125 mL/hour. Explained reason for IV. Stated understanding. ______________A. Luis, RN VARIATION: INSERTING A BUTTERFLY (WINGED-TIP) NEEDLE Hold the needle, pointed in the direction of the blood flow, at a 30degree angle, with the bevel up, and pierce the skin beside the vein about 1 cm (1/2 in.) below the site planned for piercing the vein. ■ Once the needle is through the skin, lower the needle so that it is almost parallel with the skin. Rationale: Lowering the needle reduces the chances of puncturing both sides of the vein. ■

Follow the course of the vein, and pierce one side of the vein. Sudden lack of resistance can be felt as blood enters the needle. ■ When blood flows back into the needle tubing, insert the needle to its hub. ■ Release the tourniquet, attach the infusion, and initiate flow as quickly as possible. Rationale: Attaching the tubing quickly prevents blood from clotting and obstructing the needle. ■ Secure the butterfly needle by taping it securely by the crisscross (chevron) method.  Place a small gauze square under the needle, if required. Rationale: The gauze keeps the needle in position in the vein.

Needle in vein Tape Tubing

72 HRS.–ONLY I.V. SET–__ 0800 9/11 HR._____ START DATE________ 9/14 HR._____ 0800 DISCARD DATE______ LA R.N. INITIAL_________________  Tubing labeled with date, time of attachment, and nurse’s initials. Also shown is a preprinted label.

Photographer: Elena Dorfman

 Taping the butterfly needle by the chevron method.

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EVALUATION Evaluate the following: Skin status at IV site (warm temperature and absence of pain, redness, and swelling) ■ Status of dressing ■

REGULATING AND MONITORING INTRAVENOUS INFUSIONS.

Orders for IV infusions may take several forms: “3,000 mL over 24 hours”; “1,000 mL every 8 hours × 3 bags”; “125 mL/h until oral intake is adequate.” The nurse initiating the IV calculates the correct flow rate, regulates the infusion, and monitors the client’s responses. Unless an infusion control device is used, the nurse manually regulates the drops per minute of flow using the roller clamp to ensure that the prescribed amount of solution will be infused in the correct time span. If the flow is incorrect, problems such as hypervolemia, hypovolemia, or inadequate medication administration can result. The number of drops delivered per milliliter of solution varies with different brands and types of infusion sets. This rate, called the drip factor (sometimes called the drop factor), generally is printed on the package of the infusion set. Macrodrops commonly have drop factors of 10, 12, 15, or 20 drops/mL; the drop factor for microdrip is always 60 drops/mL (Figure 52-25 ■). To calculate flow rates, the nurse must know the volume of fluid to be infused and the specific time for the infusion. Two commonly used methods of indicating flow rates are designating the number of milliliters to be administered in 1 hour (mL/h) and the number of drops to be given in 1 minute (gtt/min). Because l milliliter of fluid displaces 1 cubic centimeter of space, the volume to be infused in the first method may also be designated as cubic centimeters per hour (cc/h). Milliliters per Hour. Hourly rates of infusion can be calculated by dividing the total infusion volume by the total infusion time

Figure 52-25 ■ Infusion set spikes and drip chambers: nonvented macrodrip, vented macrodrip, nonvented microdrip.

IV flow rate consistent with that ordered Ability to perform self-care activities; understanding of any mobility limitations ■ Vital signs compared to baseline level ■ ■

in hours. For example, if 3,000 mL is infused in 24 hours, the number of milliliters per hour is 3,000 mL (total infusion volume) ⫽ 125 mL/h 24 h (total infusion time) Nurses need to check infusions at least every hour to ensure that the indicated milliliters per hour have infused and that IV patency is maintained. A strip of adhesive marking the exact time and/or amount to be infused may be taped to the solution container. Some agencies make premarked labels available (Figure 52-26 ■). Drops per Minute. The nurse initiating and monitoring an infusion must regulate the drops per minute to ensure that the prescribed amount of solution will infuse. Drops per minute are calculated by the following formula:

Total infusion volume ⫻ drop factor Drops per minute ⫽ Total time of infusion in minutes If the requirements are 1,000 mL in 8 hours and the drip factor is 20 drops/mL, the drops per minute should be 1,000 mL ⫻ 20 ⫽ 41 drops/min 8 ⫻ 60 min (480 min) Approximating this rate as 40 drops/min, the nurse regulates the drops per minute by tightening or releasing the IV tubing clamp and counting the drops for 15 seconds, then multiplying that number by 4 (e.g., 10 drops/15 sec). A number of factors influence flow rate (see Box 52–8).

Figure 52-26 ■ Timing label on an intravenous container. The first time marked (0900 hours) would be correct for a bag hung at 0800 hours with a rate of 100 mL per hour. Photographer: Elena Dorfman

SKILL 52-1

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BOX 52—8 ■

■

■ ■ ■

Factors Influencing Flow Rates

The position of the forearm. Sometimes a change in the position of the client’s arm decreases flow. Slight pronation, supination, extension, or elevation of the forearm on a pillow can increase flow. The position and patency of the tubing. Tubing can be obstructed by the client’s weight, a kink, or a clamp closed too tightly. The flow rate also diminishes when part of the tubing dangles below the puncture site. The height of the infusion bottle. Elevating the height of the infusion bottle a few inches can speed the flow by creating more pressure. Possible infiltration or fluid leakage. Swelling, a feeling of coldness, and tenderness at the venipuncture site may indicate infiltration. Relationship of the size of the angiocath to the vein. A catheter that is too large may impede the infusion flow.

DEVICES TO CONTROL INFUSIONS. A number of devices are

used to control the rate of an infusion. Electronic infusion devices (EIDs) regulate the infusion rate at preset limits. They also have an alarm that is triggered when the solution in the IV bag is low, when there is air in the tubing, or when the tubing is not high enough. The Dial-A-Flo in-line device (Figure 52-27 ■) is a regulator that controls the amount of fluid to be administered. Hospitals may stock the Dial-A-Flo for use in situations where a pump is not required, but prevention of fluid overload is important. It is preset at the volume to be infused and can be attached at the time the infusion is set up or when the tubing is changed. Another variation is a volume-control set, or Volutrol, which is used if the volume of fluid administered is to be carefully controlled. The set, which holds a maximum of 100 mL of solution, is attached below the solution container, and the drip chamber is placed below the set. Volume-control sets are frequently used in pediatric settings, where the volume administered is critical.

CLINICAL ALERT A flow rate control device should be used when administering IV fluid to elderly or pediatric clients. Both of these age groups are especially at risk for complications of fluid overload, which can occur with rapid infusion of IV fluids. ■

Figure 52-28 ■ An intravenous infusion pump. Photographer: Jenny Thomas

An infusion pump (Figures 52-28 ■ and 52-29 ■) delivers fluids intravenously by exerting positive pressure on the tubing or on the fluid. In situations where the fluid flow is unrestricted, the pump pressure is comparable to that of gravity flow. However, if restrictions develop (increased venous resistance), the pump can maintain the fluid flow by increasing the pressure applied to the fluid. A controller, by contrast, operates solely by gravitational force. The delivery pressure depends on the height of the container in relation to the venipuncture site. The container must be at least 76 cm (30 in.) above the venipuncture site for a controller to work. A controller does not have the ability to add pressure to the line and to overcome resistances to fluid flow. Skill 52-2 outlines the steps involved in monitoring an intravenous infusion.

Figure 52-27 ■ The Dial-A-Flo in-line device.

Figure 52-29 ■ Programmable infusion pumps.

Photographer: Elena Dorfman

(Courtesy of ALARIS Medical Systems, Inc., San Diego, California.)

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MONITORING AN INTRAVENOUS INFUSION SKILL 52-2

PURPOSES ■ To maintain the prescribed flow rate ■ To prevent complications associated with IV therapy ASSESSMENT Assess the following: Appearance of infusion site; patency of system Type of fluid being infused and rate of flow ■ Response of the client ■ ■

PLANNING Review the type of equipment used outside the client’s room. Read all appropriate materials and confirm the type of tubing, controller, or pump being used. IMPLEMENTATION Preparation 1. Gather the pertinent data. ● From the primary care provider’s order, determine the type and sequence of solutions to be infused. ● Determine the rate of flow and infusion schedule. Performance 1. Ensure that the correct solution is being infused. ● If the solution in incorrect, slow the rate of flow to a minimum to maintain the patency of the catheter. Rationale: Stopping the infusion may allow a thrombus to form in the IV catheter. If this occurs, the catheter must be removed and another venipuncture performed before the infusion can be resumed. ● Change the solution to the correct one. Document and report the error according to agency protocol. 2. Observe the rate of flow every hour. ● Compare the rate of flow regularly, for example, every hour, against the infusion schedule. Rationale: Infusions that are off schedule can be harmful to a client. ● If the rate is too fast, slow it so that the infusion will be completed at the planned time. Rationale: Solution administered too quickly may cause a significant increase in circulating blood volume (which is about 6 L in an adult). Hypervolemia may result in pulmonary edema and cardiac failure. Assess the client for manifestations of hypervolemia and its complications, including dyspnea; rapid, labored breathing; cough; crackles (rales) in the lung bases; tachycardia; and bounding pulses. ● If the rate is too slow, check agency practice. Some agencies permit nursing personnel to adjust a rate of flow by a specified amount. Adjustments above this rate require a primary care provider’s order. Rationale: Solution that is administered too slowly can supply insufficient fluid, electrolytes, or medication for a client’s needs. ● If the rate of flow is 150 mL/h or more, check the rate of flow more frequently, for example, every 15 to 30 minutes. 3. Inspect the patency of the IV tubing and catheter. ● Observe the position of the IV solution. If it is less than 1 m (3 ft) above the IV site, readjust it to the correct height of the pole. Rationale: If the IV bag/bottle is too low, the solution may not flow into the vein because there is insufficient grav-

Delegation This procedure should be done by the nurse because it is an important part of assessment and complications may occur.

itational pressure to overcome the pressure of the blood within the vein. ● Observe the drip chamber. If it is less than half full, squeeze the chamber to allow the correct amount of fluid to flow in. ● Open the drip regulator and observe for a rapid flow of fluid from the solution container into the drip chamber. Then partially close the drip regulator to reestablish the prescribed rate of flow. Rationale: Rapid flow of fluid into the drip chamber indicates patency of the IV line. Closing the drip regulator to the prescribed rate of flow prevents fluid overload. ● Inspect the tubing for pinches or kinks or obstructions to flow. Arrange the tubing so that it is lightly coiled and under no pressure. Sometimes the tubing becomes caught under the client’s body and the weight blocks the flow. ● Observe the position of the tubing. If it is dangling below the venipuncture, coil it carefully on the surface of the bed. Rationale: The solution may not flow upward into the vein against the force of gravity. ● Lower the solution container below the level of the infusion site and observe for a return flow of blood from the vein. Rationale: A return flow of blood indicates that the needle is patent and in the vein. Blood returns in this instance because venous pressure is greater than the fluid pressure in the IV tubing. Absence of blood return may indicate that the needle is no longer in the vein or that the tip of the catheter is partially obstructed by a thrombus, the vein wall, or a valve in the vein. ● Determine whether the bevel of the catheter is blocked against the wall of the vein. If it is blocked, pull back gently, turn it slightly, or carefully raise or lower the angle of insertion slightly, using a sterile gauze pad underneath to protect the skin and change the position of the catheter bevel. ● If there is leakage, locate the source. If the leak is at the catheter connection, tighten the tubing into the catheter. If the leak cannot be stopped, slow the infusion as much as possible without stopping it, and replace the tubing with a new sterile set. Estimate the amount of solution lost, if it was substantial. 4. Inspect the insertion site for fluid infiltration. ● When an IV needle becomes dislodged from the vein, fluid flows into interstitial tissues, causing swelling. This is known

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SKILL 52-2

MONITORING AN INTRAVENOUS TRANSFUSION continued as infiltration and is manifested by localized swelling, coolness, pallor, and discomfort at the IV site. ● If an infiltration is present, stop the infusion and remove the catheter. Restart the infusion at another site. ● Apply a warm compress to the site of the infiltration. Rationale: Warmth promotes comfort and vasodilation, facilitating absorption of the fluid from interstitial tissues. 5. If the infiltration involves a vesicant drug, it is called extravasation and other measures may be indicated. Extravasated vesicant drugs can cause severe tissue injury or destruction. The extravasation of a vesicant drug should be considered an emergency (Hadaway, 2004). ● Stop the infusion immediately. Disconnect the tubing as close to the catheter hub as possible and attempt to aspirate any drug remaining in the hub. If an injectable antidote is available, the catheter should remain in place. ● The primary care provider should be notified and if ordered, the antidote administered. ● The affected arm should be elevated and depending on the drug, heat or cold therapy should be implemented. 6. If infiltration is not evident but the infusion is not flowing, determine whether the needle is dislodged from the vein. ● Gently pinch the IV tubing adjacent to the needle site. This will cause blood to flow (flash back) into the tubing if the needle is in the vein. ● Use a sterile syringe of saline to withdraw fluid from the port near the venipuncture site. If blood does not return, discontinue the intravenous solution. 7. Inspect the insertion site for phlebitis (inflammation of a vein). ● Inspect and palpate the site at least every 8 hours. Phlebitis can occur as a result of injury to a vein, for example, because EVALUATION Evaluate the following: ■ ■

Amount of fluid infused according to the schedule Intactness of IV system

CHANGING INTRAVENOUS CONTAINERS, TUBING, AND DRESSINGS. Intravenous solution containers are changed

when only a small amount of fluid remains in the neck of the container and fluid still remains in the drip chamber. However,

of mechanical trauma or chemical irritation. Chemical injury to a vein can occur from intravenous electrolytes (especially potassium and magnesium) and medications. The clinical signs are redness, warmth, and swelling at the intravenous site and burning pain along the course of a vein. ● If phlebitis is detected, discontinue the infusion, and apply warm compresses to the venipuncture site. Do not use this injured vein for further infusions. 8. Inspect the intravenous site for bleeding. ● Oozing or bleeding into the surrounding tissues can occur while the infusion is freely flowing but is more likely to occur after the needle has been removed from the vein. ● Observation of the venipuncture site is extremely important for clients who bleed readily, such as those receiving anticoagulants. 9. Teach the client ways to maintain the infusion system, for example: ● Avoid sudden twisting or turning movements of the arm with the needle or catheter. ● Avoid stretching or placing tension on the tubing. ● Try to keep the tubing from dangling below the level of the needle. ● Notify a nurse if a. The flow rate suddenly changes or the solution stops dripping. b. The solution container is nearly empty. c. There is blood in the IV tubing. d. Discomfort or swelling is experienced at the IV site. 10. Document all relevant information.

Appearance of IV site (e.g., dry, tissue infiltration, discomfort) Urinary output compared to urinary intake ■ Tissue turgor; specific gravity of urine ■ Vital signs and lung sounds compared to baseline data ■ ■

all IV bags should be changed every 24 hours, regardless of how much solution remains, to minimize the risk of contamination. IV tubing is changed every 48 to 96 hours, depending on agency protocol, as is the site dressing. Skill 52-3 provides

SKILL 52-3

CHANGING AN INTRAVENOUS CONTAINER, TUBING, AND DRESSING PURPOSES ■ To maintain the flow of required fluids ■ To maintain sterility of the IV system and decrease the incidence of phlebitis and infection

■

ASSESSMENT Assess the following:

■

Presence of fluid infiltration, bleeding, or phlebitis at IV site Allergy to tape or iodine ■ Infusion rate and amount absorbed ■ ■

■

To maintain patency of the IV tubing To prevent infection at the IV site and the introduction of microorganisms into the bloodstream

Blockages in IV system Appearance of the dressing for integrity, moisture, and need for change ■ The date and the time of the previous dressing change ■

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CHANGING AN INTRAVENOUS CONTAINER, TUBING, AND DRESSING continued ■ ■

Timing label Sterile gauze square for positioning the needle

Delegation

For the Dressing

This procedure includes assessment of the IV site and should be completed by a registered nurse. In many states, licensed vocational nurses with IV certification may complete the procedure.

■ ■ ■ ■

Equipment ■ Container with the correct kind and amount of sterile solution ■ Administration set, including sterile tubing and drip chamber IMPLEMENTATION Preparation 1. Obtain the correct solution container. ● Read the label of the new container. ● Verify that you have the correct solution, correct client, correct additives (if any), and correct dose (number of bags or total volume ordered). Performance 1. Perform hand hygiene. 2. Set up the intravenous equipment with the new container and label all. See Skill 52-1, steps 1 to 8. ● Apply a timing label to the container. ● Prime the tubing. ● Label the tubing as shown in Figure  in Skill 52-1. 3. Prepare the IV needle or catheter, tape, and the dressing equipment near the client. ● Prepare strips of tape as needed for the type of needle or catheter. For the butterfly needle, two or three strips of 1.25-cm (1/2-in.) tape are needed. For a catheter, three strips of 1.25-cm (1/2-in.) tape are needed. These will be used later to secure the needle or catheter without covering the insertion site. ● Hang the pieces of tape from the edge of a table. Rationale: This places the tape in readiness for use without disrupting the adhesive. Ensure that the table is clean to avoid contaminating the tape. ● Open all equipment: swabs, dressing and adhesive bandage, and ointment. Rationale: This facilitates access to supplies after gloves are donned. ● Place a towel under the extremity. Rationale: This prevents soiling of bed linens. ● Apply clean gloves. 4. Remove the soiled dressing and all tape, except the tape holding the catheter or IV needle in place. ● Remove tape and gauze from the old dressing one layer at a time. Rationale: This prevents dislodgment of the catheter or needle in case tubing becomes entangled between layers of dressing. ● Remove adhesive dressings in the direction of the client’s hair growth when possible. Rationale: This minimizes discomfort when adhesive is removed from the skin. ● Discard the used dressing materials in the appropriate container.

■ ■ ■

Clean gloves Sterile 2-in. × 2-in. or 4-in. × 4-in. gauze or transparent dressing Adhesive remover Chlorhexidine swabs Alcohol swabs Tape Towel

5. Assess the IV site. ● Inspect the IV site for the presence of infiltration or inflammation. Rationale: Inflammation or infiltration necessitates removal of the IV needle or catheter to avoid further trauma to the tissues. ● Go to step 6, or discontinue and relocate the IV site if indicated. See Skills 52-1 and 52-4. 6. Disconnect the used tubing. ● Place a sterile swab under the hub of the catheter. Rationale: This absorbs any leakage that might occur when the tubing is disconnected. ● Clamp the tubing. With the fourth or fifth finger of the nondominant hand, apply pressure to the vein above the end of the catheter. Rationale: This helps prevent blood from coming out of the needle during the change of tubing. ● Holding the hub of the catheter with the thumb and index finger of the nondominant hand, loosen the tubing with the dominant hand, using a twisting, pulling motion. Rationale: Holding the catheter firmly but gently maintains its position in the vein. ● Remove the used IV tubing. ● Place the end of the tubing in the basin or other receptacle. 7. Connect the new tubing, and reestablish the infusion. ● Continue to hold the catheter and grasp the new tubing with the dominant hand. ● Remove the protective tubing cap and, maintaining sterility, insert the tubing end securely into the needle hub. Twist it to secure it. ● Open the clamp to start the solution flowing. 8. Remove the tape securing the needle or catheter. ● When removing this tape and while cleaning the site, stabilize the needle or catheter hub with one hand. Rationale: This prevents inadvertent dislodgment of the needle or catheter. 9. Clean the IV site. ● Start with adhesive remover to remove adhesive residue. Rationale: Removal of adhesive residue facilitates adherence of the new dressing. ● Then, using chlorhexidine swabs or alcohol swabs, clean the site, beginning at the catheter or needle and cleaning outward in a 2-in. diameter. Rationale: Cleaning in this manner prevents contamination of the IV site from bacteria on the peripheral skin areas. Antiseptics reduce the number of continued on page 1470

SKILL 52-3

PLANNING Review primary care provider’s orders for changes in fluid administration.

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SKILL 52-3

CHANGING AN INTRAVENOUS CONTAINER, TUBING, AND DRESSING continued microorganisms present at the site, thus reducing the risk of infection. ● Follow agency protocol about cleaning procedures. 10. Retape the needle or catheter. ● For a butterfly needle, apply strips of tape to the wings of the butterfly using the crisscross (chevron) method (Figure  in Skill 52-1). ● For a catheter; apply the tape using the U method (Figure  in Skill 52-1). ● Apply a sterile transparent dressing over the site. ● Remove gloves. 11. Label the dressing and secure IV tubing.

Place the date and time of the dressing change and your initials either on the label provided or directly over the top of the dressing. ● Secure IV tubing with additional tape as required. 12. Regulate the rate of flow of the solution according to the order on the chart. 13. Document all relevant information. ● Record the change of the solution container, tubing, and/or dressing in the appropriate place on the client’s chart. Also record the fluid intake according to agency practice. Record the number of the container if the containers are numbered at the agency. Also record your assessments. ●

EVALUATION Evaluate the following: Status of IV site Patency of IV system ■ Accuracy of flow ■ ■

guidelines for changing an IV solution container, tubing, and the IV site dressing. When an IV infusion is no longer necessary to maintain the client’s fluid intake or to provide a route for medication administration, the infusion is either discontinued and the catheter re-

moved or the catheter is left in place and converted to a saline or heparin lock. Guidelines for discontinuing an IV infusion or converting the catheter to a lock are outlined in Skills 52-4 and 52-5, respectively.

SKILL 52-4

DISCONTINUING AN INTRAVENOUS INFUSION PURPOSE ■ To discontinue an intravenous infusion when the therapy is complete or when the IV site needs to be changed ASSESSMENT Assess the following: ■ ■

■ ■

Amount of fluid infused Appearance of IV catheter

Appearance of the venipuncture site Any bleeding from the infusion site

PLANNING Review the primary care provider’s orders. Delegation This procedure should be done by a registered nurse. In many states, licensed vocational nurses may initiate and discontinue IV therapy.

IMPLEMENTATION Performance 1. Prepare the equipment. ● Clamp the infusion tubing. Rationale: Clamping the tubing prevents the fluid from flowing out of the needle onto the client or bed. ● Loosen the tape at the venipuncture site while holding the needle firmly and applying countertraction to the skin. Rationale: Movement of the needle can injure the vein and

Equipment ■ Clean gloves ■ Dry or antiseptic-soaked swabs, according to agency practice ■ Small sterile dressing and tape

cause discomfort to the client. Countertraction prevents pulling the skin and causing discomfort. ● Put on clean gloves and hold a sterile gauze above the venipuncture site. 2. Withdraw the needle or catheter from the vein. ● Withdraw the needle or catheter by pulling it out along the line of the vein. Rationale: Pulling it out in line with the vein avoids injury to the vein.

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DISCONTINUING AN INTRAVENOUS INFUSION continued

EVALUATION Evaluate the following: ■ ■

creases the possibility of the piece moving until a primary care provider is notified. 4. Cover the venipuncture site. ● Apply the sterile dressing. Rationale: The dressing continues the pressure and covers the open area in the skin, preventing infection. ● Discard the IV solution properly, if infusions are being discontinued, and discard the used supplies appropriately. 5. Document all relevant information. ● Record the amount of fluid infused on the intake and output record and on the chart, according to agency practice. Include the container number, type of solution used, time of discontinuing the infusion, and the client’s response.

■ ■

SKILL 52-4

Immediately apply firm pressure to the site, using sterile gauze, for 2 to 3 minutes. Rationale: Pressure helps stop the bleeding and prevents hematoma formation. ● Hold the client’s arm above the body if any bleeding persists. Rationale: Raising the limb decreases blood flow to the area. 3. Examine the catheter removed from the client. ● Check the catheter to make sure it is intact. Rationale: If a piece of tubing remains in the client’s vein it could move centrally (toward the heart or lungs) and cause serious problems. ● Report a broken catheter to the nurse in charge or primary care provider immediately. ● If a broken piece can be palpated, apply a tourniquet above the insertion site. Rationale: Application of a tourniquet de●

Respirations, skin color, edema, sputum, cough, and urine output How the person feels physically and psychologically

Appearance of the venipuncture site The pulse

CHANGING AN INTRAVENOUS CATHETER TO AN INTERMITTENT INFUSION LOCK

ASSESSMENT Assess the following: ■ ■

Patency of the IV catheter Appearance of the site (evidence of inflammation or infiltration)

PLANNING Review the primary care provider’s order. ■

A specific order may be written to convert an intravenous access to a heparin or saline lock. The order also may be implied, for example, IV fluids are to be discontinued but the client has orders for an IV antibiotic every 6 hours or is receiving analgesics intravenously. Delegation Due to the need for sterile technique and technical complexity, this procedure is not delegated to UAP. UAP may care for clients with such devices, and the nurse must ensure that the UAP knows what complications or adverse signs should be reported to the nurse.

IMPLEMENTATION Preparation 1. Prepare the client. ● Prior to performing the procedure, introduce self and verify the client’s identity using agency protocol. Explain the procedure to the client and the reason for leaving the IV catheter in place. Changing an IV to a heparin or saline lock should cause no discomfort other than that associated with removing tape from the IV tubing.

Equipment ■ Intermittent infusion cap or device ■ Clean gloves ■ Sterile 2-in. × 2-in. or 4-in. × 4-in. gauze ■ Sterile saline for injection (without preservative) or heparin flush solution (10 units/mL or 100 units/mL) in a prefilled syringe, a 3-mL syringe with a needleless infusion device ■ Isopropyl alcohol wipe ■ Tape ■ Clean emesis basin

Performance 1. Prepare the equipment. ● Perform hand hygiene. ● Assess the IV site (if visible) and determine the patency of the catheter (see Skill 52-2). If the catheter is not fully patent or there is evidence of phlebitis or infiltration, discontinue the catheter and establish a new IV site.

SKILL 52-5

PURPOSE ■ To permit IV administration of medications or fluids on an intermittent basis

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CHANGING AN INTRAVENOUS CATHETER TO AN INTERMITTENT INFUSION LOCK continued Expose the IV catheter hub and loosen any tape that is holding the IV tubing in place or that will interfere with insertion of the intermittent infusion plug into the catheter. ● Clamp the IV tubing to stop the flow of IV fluid. ● Open the gauze pad and place it under the IV catheter hub. ● Open the alcohol wipe and intermittent infusion plug, leaving the plug in its sterile package. 2. Remove the IV tubing and insert the intermittent infusion plug into the IV catheter. ● Put on gloves. ● Stabilize the IV catheter with your nondominant hand and use the little finger to place slight pressure on the vein above the end of the catheter. Twist the IV tubing adapter to loosen it from the IV catheter and remove it, placing the end of the tubing in a clean emesis basin. ● Pick up the intermittent infusion plug from its package and remove the protective sleeve from the male adapter, maintaining its sterility. Insert the plug into the IV catheter, twisting it to seat it firmly or engage the Luer lock.

SKILL 52-5

●

3. Instill saline or heparin solution per agency policy. Rationale: Saline or heparin are used to maintain patency of the IV catheter when fluids are not infusing through the catheter. 4. Tape the intermittent infusion plug in place using a chevron or U method. Rationale: Tape provides added security to prevent the infusion plug from coming out of the intravenous catheter. It also promotes comfort, preventing the plug from catching on clothing or bedding. 5. Teach the client how to maintain the lock. ● Avoid manipulating the catheter or infusion plug and protect it from catching on clothing or bedding. A gauze bandage such as Kerlix or Kling may be wrapped over the plug when it is not in use to protect it. ● Cover the site with an occlusive dressing when showering; avoid immersing the site. ● Flush the catheter with saline or heparin solution as directed. ● Notify the nurse or primary care provider if the plug or catheter comes out; if the site becomes red, inflamed, or painful; or if any drainage or bleeding occurs at the site. 6. Document all relevant information.

EVALUATION Evaluate the following: Patency of the catheter Appearance of the site ■ Ease of flushing ■ ■

Blood Transfusions Intravenous fluids can be effective in restoring intravascular (blood) volume; however, they do not affect the oxygencarrying capacity of the blood. When red and white blood cells, platelets, or blood proteins are lost because of hemorrhage or disease, it may be necessary to replace these components to restore the blood’s ability to transport oxygen and carbon dioxide, to clot, to fight infection, and to keep extracellular fluid within the intravascular compartment. A blood transfusion is the introduction of whole blood or blood components into the venous circulation. BLOOD GROUPS. Human blood is commonly classified into four main groups (A, B, AB, and O). The surface of an individual’s red blood cells contains a number of proteins known

CULTURALLY COMPETENT CARE Blood and Blood Products

as antigens that are unique for each person. Many blood antigens have been identified, but the antigens A, B, and Rh are the most important in determining blood group or type. Because antigens promote agglutination or clumping of blood cells, they are also known as agglutinogens. The A antigen or agglutinogen is present on the RBCs of people with blood group A, the B antigen is present in people with blood group B, and both A and B antigens are found on the RBC surface in people with group AB blood. Neither antigen is present in people with group O blood. Preformed antibodies to RBC antigens are present in the plasma; these antibodies are often called agglutinins. People with blood group A have B antibodies (agglutinins); A antibodies are present in people with blood group B; and people with blood group O have antibodies to both A and B antigens. People with group AB blood do not have antibodies to either A or B antigens (Table 52–11). When blood is transfused, the blood

■

TABLE 52–11 The Blood Groups with Their Constituent Agglutinogens and Agglutinins

Note: From Transcultural Concepts in Nursing Care (4th ed.) (pp. 470, 481), by M. M. Andrews and J. S. Boyle, 2003, Philadelphia: Lippincott Williams & Wilkins. Reprinted with permission.

BLOOD TYPES A B AB O

Jehovah’s Witnesses do not receive blood or blood products. Blood volume expanders are acceptable if they are not derivatives of blood. ■ Christian Scientists do not ordinarily use blood or blood products.

RBC ANTIGENS (AGGLUTINOGENS) A B A and B —

PLASMA ANTIBODIES (AGGLUTININS) B A — A and B

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group of the donor and recipient must match to avoid an antigen-antibody reaction and destruction (hemolysis) of RBCs. RHESUS (RH) FACTOR.

The Rh factor antigen is present on the RBCs of approximately 85% of the people in the United States. Blood that contains the Rh factor is known as Rhpositive (Rh⫹); when it is not present the blood is said to be Rh-negative (Rh⫺). In contrast to the ABO blood groups, Rh⫺ blood does not naturally contain Rh antibodies. However, on exposure to blood containing Rh factor (e.g., an Rh⫺ mother carrying a fetus with Rh⫹ blood, or transfusion of Rh⫹ blood into a client who is Rh⫺), Rh antibodies develop. Subsequent exposures to Rh⫹ blood place the client at risk for an antigen–antibody reaction and hemolysis of RBCs. BLOOD TYPING AND CROSSMATCHING.

To avoid transfusing incompatible red blood cells, both blood donor and recipient are typed and their blood crossmatched. Blood typing is done to determine the ABO blood group and Rh factor status. This test is also performed on pregnant women and neonates to assess for possible intrauterine exposure of either to an incompatible blood type (particularly Rh factor incompatibilities). Because blood typing only determines the presence of the major ABO and Rh antigens, crossmatching also is necessary prior to transfusion to identify possible interactions of minor antigens with their corresponding antibodies. RBCs from the donor blood are mixed with serum from the recipient; a reagent (Coombs’ serum) is added, and the mixture is examined for visible agglutination. If no antibodies to the donated RBCs are present in the recipient’s serum, agglutination does not occur and the risk of transfusion reaction is small.

SELECTION OF BLOOD DONORS. Screening of blood donors

is rigorous. Criteria have been established to protect the donor from possible ill effects of donation and to protect the recipient from exposure to diseases transmitted through the blood. Blood donors are unpaid volunteers. Potential donors are

TABLE 52–12

eliminated by a history of hepatitis, HIV infection (or risk factors for HIV infection), heart disease, most cancers, severe asthma, bleeding disorders, or convulsions. Donation may be deferred for people with malaria or who have been exposed to malaria or hepatitis or in situations of pregnancy, surgery, anemia, high or low blood pressure, and certain drugs. BLOOD AND BLOOD PRODUCTS FOR TRANSFUSION. Most

clients do not require transfusion of whole blood. It is more common for clients to receive a transfusion of a particular blood component specific to their individual needs. Table 52–12 lists some of the common blood products that may be transfused. TRANSFUSION REACTIONS. Transfusion of ABO- or Rhincompatible blood can result in a hemolytic transfusion reaction with destruction of the transfused RBCs and subsequent risk of kidney damage or failure. Other forms of transfusion reaction also may occur, including febrile, allergic, circulatory overload, and sepsis. Because the risk of an adverse reaction is high when blood is transfused, clients must be frequently and carefully assessed before and during transfusion. Many reactions become evident within 5 to 15 minutes of initiating the transfusion but they can develop any time during a transfusion; clients are closely monitored during the initial period of the transfusion. Stop the transfusion immediately if signs of a reaction develop. Possible transfusion reactions, their clinical signs, and nursing implications are listed in Table 52–13. ADMINISTERING BLOOD. Special precautions are necessary

when administering blood. When a transfusion is ordered, obtain the blood from the blood bank just before starting the transfusion. Do not store the blood in the refrigerator on the nursing unit; lack of temperature control may damage the blood. Once blood or a blood product is removed from the refrigerator, there is a limited amount of time to administer it (e.g., packed RBCs should not hang for more than 4 hours after being removed from the refrigerator). Follow agency policies

Blood Products for Transfusion

PRODUCT Whole blood Packed red blood cells (PRBCs)

Autologous red blood cells Platelets

Fresh frozen plasma

Albumin and plasma protein fraction Clotting factors and cryoprecipitate

USE Not commonly used except for extreme cases of acute hemorrhage. Replaces blood volume and all blood products: RBCs, plasma, plasma proteins, fresh platelets, and other clotting factors. Used to increase the oxygen-carrying capacity of blood in anemias, surgery, and disorders with slow bleeding. One unit of PRBCs has the same amount of oxygen-carrying RBCs as a unit of whole blood (Rosenthal, 2004, p. 23). One unit raises hematocrit by approximately 2% to 3%. Used for blood replacement following planned elective surgery. Client donates blood for autologous transfusion 4–5 weeks prior to surgery. Replaces platelets in clients with bleeding disorders or platelet deficiency. Fresh platelets most effective. Each unit should increase the average adult client’s platelet count by about 5,000 platelets/microliter (Rosenthal, 2004, p. 24). Expands blood volume and provides clotting factors. Does not need to be typed and crossmatched (contains no RBCs). Each unit will increase the level of any clotting factor by 2% to 3% in the average adult (Rosenthal, 2004, p. 26). Blood volume expander; provides plasma proteins. Used for clients with clotting factor deficiencies. Each provides different factors involved in the clotting pathway; cryoprecipitate also contains fibrinogen.

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TABLE 52–13

Transfusion Reactions

REACTION: CAUSE Hemolytic reaction: incompatibility between client’s blood and donor’s blood

CLINICAL SIGNS Chills, fever, headache, backache, dyspnea, cyanosis, chest pain, tachycardia, hypotension

Febrile reaction: sensitivity of the client’s blood to white blood cells, platelets, or plasma proteins

Fever; chills; warm, flushed skin; headache; anxiety; muscle pain

Allergic reaction (mild): sensitivity to infused plasma proteins

Flushing, itching, urticaria, bronchial wheezing

Allergic reaction (severe): antibody–antigen reaction

Dyspnea, chest pain, circulatory collapse, cardiac arrest

Circulatory overload: blood administered faster than the circulation can accommodate

Cough, dyspnea, crackles (rales), distended neck veins, tachycardia, hypertension

Sepsis: contaminated blood administered

High fever, chills, vomiting, diarrhea, hypotension

NURSING INTERVENTION* 1. Discontinue the transfusion immediately. NOTE: When the transfusion is discontinued, the blood tubing must be removed as well. Use new tubing for the normal saline infusion. 2. Maintain vascular acess with normal saline, or according to agency protocol. 3. Notify the primary care provider immediately. 4. Monitor vital signs. 5. Monitor fluid intake and output. 6. Send the remaining blood, bag, filter, tubing, a sample of the client’s blood, and a urine sample to the laboratory. 1. Discontinue the transfusion immediately. 2. Give antipyretics as ordered. 3. Notify the primary care provider. 4. Keep the vein open with a normal saline infusion. 1. Stop or slow the transfusion, depending on agency protocol. 2. Notify the primary care provider. 3. Administer medication (antihistamines) as ordered. 1. Stop the transfusion. 2. Keep the vein open with normal saline. 3. Notify the primary care provider immediately. 4. Monitor vital signs. Administer cardiopulmonary resuscitation if needed. 5. Administer medications and/or oxygen as ordered. 1. Place the client upright, with feet dependent. 2. Stop or slow the transfusion. 3. Notify the primary care provider. 4. Administer diuretics and oxygen as ordered. 1. Stop the transfusion. 2. Keep the vein open with a normal saline infusion. 3. Notify the primary care provider. 4. Administer IV fluids, antibiotics. 5. Obtain a blood specimen from the client for culture. 6. Send the remaining blood and tubing to the laboratory.

*

Nurses should follow the agency’s protocol regarding interventions. These may vary among agencies.

for verifying that the unit is correct for the client. The U.S. Food and Drug Administration (FDA) requires blood products to have bar codes to allow for scanning and machine-readable information on blood and blood component container labels to help reduce medication errors (FDA, 2004). Blood is usually administered through a #18- to #20-gauge intravenous needle or catheter; using a smaller needle may slow the infusion and damage blood cells (although a smaller gauge needle may be necessary for small children or clients with small, fragile veins). AY-type blood transfusion set with an in-line or add-on filter is used when administering blood (Figure 52-30 ■). One arm of the administration set connects to the blood; normal saline (0.9% NaCl) is attached to the other arm of the Y-type set. Saline is used to prime the set and flush the needle before administering blood. It also provides a means to keep the vein open should a transfusion reaction occur. No other IV solu-

tions should be administered with blood; they may cause the blood cells to clump or cause clotting. A transfusion should be completed within 4 hours of initiation. The risk of sepsis increases if blood hangs for a longer period. Blood tubing is changed after every 4 to 6 units per agency policy; new intravenous tubing is used following a transfusion.

CLINICAL ALERT Normal saline should always be used when giving a blood transfusion. If the client has an infusion of dextrose, stop that infusion and flush the line with saline prior to initiating the transfusion. Solutions other than saline can cause damage to the blood components. ■

To initiate, maintain, and terminate a blood transfusion, see Skill 52-6.

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Upper clamps

Drip chamber

Blood filter chamber

Main flow rate clamp

Slide clamp Y-Injection site

Adapter

Figure 52-30 ■ Schematic of a Y-set for blood administration.

INITIATING, MAINTAINING, AND TERMINATING A BLOOD TRANSFUSION USING A Y-SET ■

ASSESSMENT Assess the following:

■

■

Clinical signs of reaction (e.g., sudden chills, fever, nausea, itching, rash, low back pain, dyspnea)

PLANNING Verify the primary care provider order for transfusion. ■ Verify client consent and obtain baseline data before the transfusion. ■ Verify that a signed consent form was obtained. ■ Assess vital signs for baseline data, including blood pressure, pulse, respiratory rate and depth, and temperature. ■

To provide plasma factors, such as antihemophilic factor (AHF) or factor VIII, or platelet concentrates, which prevent or treat bleeding

Manifestations of hypervolemia Status of infusion site ■ Any unusual symptoms ■

Determine any known allergies or previous adverse reactions to blood. ■ Note specific signs related to the client’s pathology and the reason for the transfusion. For example, for an anemic client, note the hemoglobin and hematocrit levels. ■

continued on page 1476

SKILL 52-6

PURPOSES ■ To restore blood volume after severe hemorrhage ■ To restore the oxygen-carrying capacity of the blood

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SKILL 52-6

INITIATING, MAINTAINING, AND TERMINATING A BLOOD TRANSFUSION USING A Y-SET continued Delegation Due to the need for sterile technique and technical complexity, blood transfusion is not delegated to UAP. The nurse must ensure that the UAP knows what complications or adverse signs can occur and should be reported to the nurse.

Equipment ■ Blood product ■ Blood administration set IMPLEMENTATION Preparation 1. Prepare the client. ● Prior to performing the procedure, introduce self and verify the client’s identity using agency protocol. ● Explain the procedure and its purpose to the client. Instruct the client to report promptly any sudden chills, nausea, itching, rash, dyspnea, back pain, or other unusual symptoms. ● If the client has an intravenous solution infusing, check whether the needle and solution are appropriate to administer blood. The preferred needle size is from #18 to #20 gauge, and the solution must be normal saline. Dextrose (which causes lysis of RBCs), Ringer’s solution, medications and other additives, and hyperalimentation solutions are incompatible. Refer to step 5 below if the infusing solution is not compatible. ● If the client does not have an IV solution infusing, check agency policies. In some agencies an infusion must be running before the blood is obtained from the blood bank. In this case, you will need to perform a venipuncture on a suitable vein (see Skill 52-1) and start an IV infusion of normal saline. Performance 1. Obtain the correct blood component for the client. ● Check the primary care provider’s order with the requisition. ● Check the requisition form and the blood bag label with a laboratory technician or according to agency policy. Specifically, check the client’s name, identification number, blood type (A, B, AB, or O) and Rh group, the blood donor number, and the expiration date of the blood. Observe the blood for abnormal color, RBC clumping, gas bubbles, and extraneous material. Return outdated or abnormal blood to the blood bank. ● With another nurse (most agencies require an RN), compare the laboratory blood record with a. The client’s name and identification number. b. The number on the blood bag label. c. The ABO group and Rh type on the blood bag label. ● If any of the information does not match exactly, notify the charge nurse and the blood bank. Do not administer blood until discrepancies are corrected or clarified. ● Sign the appropriate form with the other nurse according to agency policy. ● Make sure that the blood is left at room temperature for no more than 30 minutes before starting the transfusion. Rationale: RBCs deteriorate and lose their effectiveness after 2 hours at room temperature. Lysis of RBCs releases potassium into the bloodstream, causing hyperkalemia.

■ ■ ■

■ ■ ■ ■

2.

3.

4.

5.

250 mL normal saline for infusion IV pole Venipuncture set containing a #18- to #20-gauge needle or catheter (if one is not already in place) or, if blood is to be administered quickly, a larger catheter Chlorhexidine solution Alcohol swabs Tape Clean gloves Agencies may designate different times at which the blood must be returned to the blood bank if it has not been started. Rationale: As blood components warm, the risk of bacterial growth also increases. If the start of the transfusion is unexpectedly delayed, return the blood to the blood bank. Do not store blood in the unit refrigerator. Rationale: The temperature of unit refrigerators is not precisely regulated and the blood may be damaged. Verify the client’s identity according to agency protocol. ● Check the client’s arm band for name and ID number. Do not administer blood to a client without an arm band. Set up the infusion equipment. ● Ensure that the blood filter inside the drip chamber is suitable for whole blood or the blood components to be transfused. Attach the blood tubing to the blood filter, if necessary. Rationale: Blood filters have a surface area large enough to allow the blood components through easily but are designed to trap clots. ● Put on gloves. ● Close all clamps on the Y-set: the main flow rate clamp and both Y-line clamps. ● Using a twisting motion, insert the piercing pin (spike) into a container of 0.9% saline solution. ● Hang the container on the IV pole about 1 m (36 in.) above the venipuncture site. Prime the tubing. ● Open the upper clamp on the normal saline tubing and squeeze the drip chamber until it covers the filter and onethird of the drip chamber above the filter. ● Tap the filter chamber to expel any residual air in the filter. ● Remove the adapter cover at the tip of the blood administration set. ● Open the main flow rate clamp, and prime the tubing with saline. ● Close both clamps. Start the saline solution. ● If an IV solution incompatible with blood is infusing, stop the infusion and discard the solution and tubing according to agency policy. ● Attach the blood tubing primed with normal saline to the intravenous catheter. ● Open the saline and main flow rate clamps and adjust the flow rate. Use only the main flow rate clamp to adjust the rate. ● Allow a small amount of solution to infuse to make sure there are no problems with the flow or with the venipuncture site. Rationale: Infusing normal saline before initiating the transfusion also clears the IV catheter of incompatible solutions or medications.

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INITIATING, MAINTAINING, AND TERMINATING A BLOOD TRANSFUSION USING A Y-SET continued

SAMPLE DOCUMENTATION

1/21/2008 1400 1 unit of PRBCs (#65234) hung to be infused over 3 hours. IV site in (L) forearm with 19 G angiocath. VS taken (see transfusion record). Informed to contact nurse if begins to experience any discomfort during transfusion. Stated he would use the call light. ____________________________C. Jones, RN. 10. Monitor the client. ● Fifteen minutes after initiating the transfusion, check the vital signs of the client. If there are no signs of a reaction, establish the required flow rate. Most adults can tolerate receiving one unit of blood in 1 1/2 to 2 hours. Do not transfuse a unit of blood for longer than 4 hours. ● Assess the client including vital signs every 30 minutes or more often, depending on the health status, until 1 hour post-transfusion. If the client has a reaction and the blood is discontinued, send the blood bag and tubing to the laboratory for investigation of the blood. 11. Terminate the transfusion. ● Put on clean gloves.

SKILL 52-6

6. Prepare the blood bag. ● Invert the blood bag gently several times to mix the cells with the plasma. Rationale: Rough handling can damage the cells. ● Expose the port on the blood bag by pulling back the tabs.
● Insert the remaining Y-set spike into the blood bag. ● Suspend the blood bag. ● Close the upper clamp below the IV saline solution on the Y-set. ● Open the clamp on the blood arm of the Y-set and prime the tubing. 7. Establish the blood transfusion. ● The blood will run into the saline-filled drip chamber. If necessary, squeeze the drip chamber to reestablish the liquid level with drip chamber one-third full. (Tap the filter to expel any residual air within the filter.) ● Readjust the flow rate with the main clamp. 8. Observe the client closely for the first 5 to 10 minutes. ● Run the blood slowly for the first 15 minutes at 20 drops per minute. ● Note adverse reactions, such as chilling, nausea, vomiting, skin rash, or tachycardia. Rationale: The earlier a transfusion reaction occurs, the more severe it tends to be. Identifying such reactions promptly helps to minimize the consequences. ● Remind the client to call a nurse immediately if any unusual symptoms are felt during the transfusion. ● If any of these reactions occur, report these to the nurse in charge and take appropriate nursing action (see Table 52–13). 9. Document relevant data. ● Record starting the blood, including vital signs, type of blood, blood unit number, sequence number (e.g., no. 1 of three ordered units), site of the venipuncture, size of the needle, and drip rate.


Exposing the port on the blood bag by pulling back the tabs. If no infusion is to follow, clamp the blood tubing and remove the needle. If another transfusion is to follow, clamp the blood tubing and open the saline infusion arm. Blood administration sets are changed within 24 hours or after 4 to 6 units of blood per agency protocol. ● If the primary IV is to be continued, flush the maintenance line with saline solution. Disconnect the blood tubing system and reestablish the intravenous infusion using new tubing. Adjust the drip to the desired rate. Often a normal saline or other solution is kept running in case of delayed reaction to the blood. ● Discard the administration set according to agency practice. Needles should be placed in a labeled, puncture-resistant container designed for such disposal. Blood bags and administration sets should be bagged and labeled before being sent for decontamination and processing. See agency policy. ● Remove gloves. ● Again monitor vital signs. 12. Follow agency protocol for appropriate disposition of the blood bag. ● On the requisition attached to the blood unit, fill in the time the transfusion was completed and the amount transfused. ● Attach one copy of the requisition to the client’s record and another to the empty blood bag. ● Return the blood bag and requisition to the blood bank. 13. Document relevant data. ● Record completion of the transfusion, the amount of blood absorbed, the blood unit number, and the vital signs. If the primary intravenous infusion was continued, record connecting it. Also record the transfusion on the IV flow sheet and I & O record. ●

SAMPLE DOCUMENTATION

1/21/2008 1410 C/O feeling warm, headache and backace. Skin flushed. Temp. 102.6, BP. 140/90, P. 112, R. 28. Approximately 50–100 cc infused. Infusion stopped. Tubing changed and NS infusing at 15 cc/hr. Dr. Riley notified. ______________________C. Jones, RN continued on page 1478

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SKILL 52-6

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INITIATING, MAINTAINING, AND TERMINATING A BLOOD TRANSFUSION USING A Y-SET continued EVALUATION Evaluate the following: ■ ■

Changes in vital signs or health status Presence of chills, nausea, vomiting, or skin rash

Evaluating Using the overall goals identified in the planning stage of maintaining or restoring fluid balance, maintaining or restoring pulmonary ventilation and oxygenation, maintaining or restoring normal balance of electrolytes, and preventing associated risks of fluid, electrolyte, and acid–base imbalances, the nurse collects data to evaluate the effectiveness of interventions. Examples of desired outcomes for the identified goals are found in Identifying Nursing Diagnoses, Outcomes, and Interventions on pages 1451 and 1452. If desired outcomes are not achieved, the nurse, client, and support person if appropriate need to explore the reasons before

NURSING CARE PLAN

modifying the care plan. For example, if the outcome “Urine output is greater than 1,300 mL per day and within 500 mL of intake” is not achieved, questions to be considered might include ■ ■ ■ ■

■

Have other outcome measures for the goal of achieving fluid balance been met? Does the client understand and comply with planned fluid intake? Is all urinary output being measured? Are unusual or excessive amounts of fluid being lost by another route (e.g., gastric suction, excessive perspiration, fever, rapid respiratory rate, wound drainage)? Are prescribed medications being taken or administered as ordered?

Deficient Fluid Volume

ASSESSMENT DATA

NURSING DIAGNOSIS

DESIRED OUTCOMES*

Nursing Assessment Merlyn Chapman, a 27-year-old sales clerk, reports weakness, malaise, and flu-like symptoms for 3–4 days. Although thirsty, she is unable to tolerate fluids because of nausea and vomiting, and she has liquid stools 2–4 times per day.

Deficient Fluid Volume related to nausea, vomiting, and diarrhea as evidenced by decreased urine output, increased urine concentration, weakness, fever, decreased skin/tongue turgor, dry mucous membranes, increased pulse rate, and decreased blood pressure

Electrolyte & Acid/Base Balance [0600] as evidenced by not compromised: • Serum electrolytes • Muscle strength

Physical Examination

Diagnostic Data

Height: 160 cm (5′3′′) Weight: 66.2 kg (146 lb) Mild fever: 38.6°C (101.5°F) Pulse: 86 BPM Respirations: 24/minute Scant urine output BP: 102/84 mm Hg Dry oral mucosa, furrowed tongue, cracked lips

Urine specific gravity: 1.035 Serum sodium 155 mEq/L Serum potassium 3.2 mEq/L Chest x-ray negative

NURSING INTERVENTIONS*/SELECTED ACTIVITIES

Fluid Balance [0601] as evidenced by not compromised: • 24-hour intake and output balance • Urine specific gravity • Blood pressure, pulse, and body temperature • Skin turgor • Moist mucous membranes

RATIONALE

Electrolyte Management: Hypokalemia [2007] Obtain specimens for analysis of altered potassium levels (e.g., serum and urine potassium) as indicated.

Urine and serum analysis provides information about extracellular levels of potassium. There is no practical way to measure intracellular K⫹.

Administer prescribed supplemental potassium (PO, NG, or IV) per policy.

Low potassium levels are dangerous and Mrs. Chapman may require supplements.

Monitor for neurologic and neuromuscular manifestations of hypokalemia (e.g., muscle weakness, lethargy, altered level of consciousness).

Potassium is a vital electrolyte for skeletal and smooth muscle activity.

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NURSING CARE PLAN Deficient Fluid Volume continued

NURSING INTERVENTIONS*/SELECTED ACTIVITIES

RATIONALE

Monitor for cardiac manifestations of hypokalemia (e.g., hypotension, tachycardia, weak pulse, rhythm irregularities).

Many cardiac rhythm disorders can result from hypokalemia. It is critical to monitor cardiac function with hypokalemia.

Electrolyte Management: Hypernatremia [2004] Obtain specimens for analysis of altered sodium levels (e.g., serum and urine sodium, urine osmolality, and urine specific gravity) as indicated.

Urine analysis provides information about retention or loss of sodium and the ability of the kidneys to concentrate or dilute urine in response to fluid changes.

Provide frequent oral hygiene.

Oral mucous membranes become dry and sticky due to loss of fluid in the interstitial spaces.

Monitor for neurologic and neuromuscular manifestations of hypernatremia (e.g., lethargy, irritability, seizures, and hyperreflexia).

Hypernatremia, as a result of low fluid volume, creates a hypertonic vascular space, which causes water to move out of the cells, including brain cells. This accounts for neurologic symptoms.

Monitor for cardiac manifestations of hypernatremia (e.g., tachycardia, orthostatic hypotension).

The heart responds to a loss of fluid by increasing the heart rate to compensate with an increase in cardiac output. Low fluid volume leads to a fall in blood pressure.

Fluid Management [4120] Weigh daily and monitor trends.

Weight helps to assess fluid balance.

Maintain accurate I & O record.

Accurate records are critical in assessing the patient’s fluid balance.

Monitor vital signs as appropriate.

Vital sign changes such as increased heart rate, decreased blood pressure, and increased temperature indicate hypovolemia.

Give fluids as appropriate.

As her nausea decreases encourage her oral intake of fluids as tolerated, again to replace lost volume.

Administer IV therapy as prescribed.

Mrs. Chapman has signs of severe fluid volume deficit. She will probably require intravenous replacement of fluid. This is especially true because her oral intake is limited because of nausea and vomiting.

EVALUATION Outcomes met. Mrs. Chapman remained hospitalized for 48 hours. She required fluid replacement of a total of 5 liters. Her blood pressure increased to 122/74, pulse rate decreased to a resting level of 74, and respirations decreased to 12/minute. Her urine output increased as the fluid was replaced and was adequate at > 0.5 mL/kg/hour by the time of discharge. The urine specific gravity was 1.015. Lab work on the day of discharge was: K⫹: 3.8 and Na⫹: 140. She had elastic skin turgor and moist mucous membranes. She was taking oral fluids and was able to discuss symptoms of deficient fluid volume that would necessitate her calling her health care provider. *

The NOC # for desired outcomes and the NIC # for nursing interventions and seleted activities are listed in brackets following the appropriate outcome or intervention. Outcomes, interventions, and activities selected are only a sample of those suggested by NOC and NIC and should be further individualized for each client.

APPLYING CRITICAL THINKING 1. What action would you take if Mrs. Chapman’s heart became irregular? 2. Mrs. Chapman is responding inappropriately to your questions; she seems to be confused. What do you think is happening? 3. Offer suggestions for ways to help Mrs. Chapman increase her oral intake.

4. Mrs. Chapman asks why you weigh her every morning. How do you respond? See Critical Thinking Possibilities in Appendix A.

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Deficient Fluid Volume

CONCEPT MAP

MC 27 y.o. female

• Sales clerk, Reports weakness, malaise, and flu-like symptoms for 3-4 days. Although thirsty, is unable to tolerate fluids because of nausea and vomiting, and she has liquid stools 2-4 times per day.

assess

• Height: 160 cm (5' 3") • Weight: 66.2 kg (146 lbs) • T: 38.6°C; P: 96 BPM; • R: 24; BP: 102/84 • Dry mucous membranes • Decreased skin turgor

• • • •

Urine specific gravity: 1.035 Serum sodium: 155 mEq/L Serum potassium 3.2 mEq/L Chest x-ray negative

generate nursing diagnosis

Deficient Fluid Volume r/t nausea, vomiting, diarrhea aeb decreased urine output, increased urine concentration, weakness, fever, decreased skin turgor, dry mucous membranes, increased pulse, and decreased BP outcome outcome Outcomes met: • BP: 122/74 • P: 74 • Urine output increased • Specific gravity: 1.105 • Moist mucous membranes • Elastic skin turgor

evaluation

Fluid balance aeb not compromised • 24 hour intake and output • Blood pressure, pulse, and temperature • Skin turgor • Urine specific gravity • Mucous membranes

nursing intervention

Electrolyte and Acid/ Base Balance aeb not compromised • Serum electrolytes • Muscle strength

nursing intervention

nursing intervention

Electrolyte Management: Hypernatremia

Fluid Management

evaluation

Outcomes met: • Serum potassium: 3.8 mEq/L • Serum sodium: 140 mEq/L

Behavior Modification

activity

activity

activity

activity Give fluids as appropriate

Weigh daily and monitor trends

activity

Provide frequent oral hygiene activity

Administer IV therapy as prescribed activity activity

Monitor vitals signs as appropriate

Maintain accurate intake and output record

activity

Monitor for neurologic and neuromuscular manifestations of hypokalemia (e.g., hypotension, tachycardia, weak pulse, rhythm irregularities)

Obtain specimens for analysis of altered potassium levels as indicated

activity Monitor for cardiac manifestations of hpyernatremia (e.g., tachycardia, orthostatic hypotension)

Monitor for neurologic and neuromuscular manifestations of hypernatremia (e.g., lethargy, irritability, seizures, and hyperreflexia) activity

Obtain specimens for analysis of altered sodium levels (e.g., serum and urine sodium, urine osmolality, and urine specific gravity) as indicated

activity

Administer prescribed supplemental potassium (PO, NG, or IV) per policy

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CHAPTER 52 REVIEW CHAPTER HIGHLIGHTS ■ ■

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A balance of fluids, electrolytes, acids, and bases in the body is necessary for health and life. The body fluid is divided into two major compartments: the intracellular fluid (ICF) inside the cells and extracellular fluid (ECF) outside the cells. Extracellular fluid is subdivided into two compartments: intravascular (plasma) and interstitial. It constitutes about onefourth to one-third of total body fluid. ECF is in constant motion throughout the body. It is the transport system that carries nutrients to and waste products from the cells. The percentage of total body fluids varies according to the individual’s age, body fat, and sex. The younger the person, the higher the proportion of water in the body. The less body fat present, the greater the proportion of body fluid. Postadolescent females have a smaller percentage of fluid in relation to total body weight than do men. There are two types of body electrolytes (ions): positively charged ions (cations) and negatively charged ions (anions). The principal ions of ECF are sodium and chloride; the principal ions of ICF are potassium and phosphate. Fluids and electrolytes move among the body compartments by osmosis, diffusion, filtration, and active transport. The major fluid pressures exerted as part of the movement of fluid and electrolytes from one compartment to another are osmotic pressure and hydrostatic pressure. The three sources of body fluid are fluids taken orally, food ingested, and the oxidation of food. Fluid intake is regulated by the thirst mechanism. Fluid output occurs chiefly through excretion of urine, although body fluid is also lost through sweat, feces, and insensible vapor loss. In healthy adults, measurable fluid intake and output should balance (about 1,500 mL per day). The output of urine normally approximates the oral intake of fluids. Water from food and oxidation is balanced by fluid loss through the skin, respiratory process, and feces. A number of body systems and organs are involved in regulating the volume and composition of body fluids: the kidneys, the endocrine system, the cardiovascular system, the lungs, and the gastrointestinal system. The kidneys are the primary regulator of fluid and electrolyte balance. Substances such as the antidiuretic hormone, the reninangiotensin-aldosterone system, and the atrial natriuretic factor are also involved in maintaining fluid balance. Fluid imbalances include a. Fluid volume deficit (FVD), also referred to as hypovolemia. b. Fluid volume excess (FVE), also referred to as hypervolemia. c. Dehydration, a deficit in water and increase in serum sodium level. d. Overhydration, an excess of water and decrease in serum sodium level. The most common electrolyte imbalances are deficits or excesses in sodium, potassium, and calcium. The acid–base balance (pH range) of body fluids is maintained within a precise range of 7.35 to 7.45.

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Acid–base balance is regulated by buffers that neutralize excess acids or bases; the lungs, which eliminate or retain carbon dioxide, a potential acid; and the kidneys, which excrete or conserve bicarbonate and hydrogen ions. Acid–base imbalance occurs when the normal 20-to-1 ratio of bicarbonate to carbonic acid is upset. Imbalances may be either respiratory or metabolic in origin; either can result in acidosis or alkalosis. Factors that influence an individual’s fluid, electrolyte, and acid–base balance include age, gender and body size, environmental temperature, and lifestyle. Illness, trauma, surgery, and certain medications can place individuals at risk for fluid, electrolyte, and acid–base imbalances. Fluid, electrolyte, and acid–base imbalance is most accurately determined through laboratory examination of blood plasma. Assessment relative to fluid, electrolyte, and acid–base balances includes (a) a nursing history; (b) physical examination of the skin, oral cavity, eyes, jugular vein, veins of the hand, and the neurologic system; (c) measurement of body weight, vital signs, and fluid intake and output; and (d) various diagnostic studies of blood and urine. A nursing history includes data about the client’s fluid and food intake; fluid output; signs of fluid, electrolyte, and acid–base imbalances; and medications, therapies, or disease processes that may disrupt these balances. NANDA-approved nursing diagnoses that relate specifically to fluid, electrolyte, and acid–base imbalances include Deficient Fluid Volume, Excess Fluid Volume, Risk for Imbalanced Fluid Volume, Risk for Deficient Fluid Volume, and Impaired Gas Exchange. Other diagnoses that may be relevant are Impaired Oral Mucous Membrane, Impaired Skin Integrity, Decreased Cardiac Output, Impaired Tissue Perfusion, Activity Intolerance, Risk for Injury, and Acute Confusion. In many instances, fluids and electrolytes can be provided orally to clients who are experiencing or at risk of developing fluid deficits. The nurse needs to establish with the client a 24-hour plan for ingesting the necessary fluids and to respect the client’s fluid preferences. For clients with fluid retention, fluids may need to be restricted; a schedule and short-term goals that make the fluid restriction more tolerable need to be developed. For clients experiencing excessive fluid losses, the administration of fluids and electrolytes intravenously is necessary. Meticulous aseptic technique is required when caring for clients with intravenous infusions. Preventing complications such as infiltration, phlebitis, hypervolemia (circulatory overload), and infection is an important aspect of intravenous therapy. The administration of blood transfusions involves accurately matching and identifying the blood for the individual, correctly identifying the recipient, and monitoring the client throughout the procedure for transfusion reactions.

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TEST YOUR KNOWLEDGE 6. Which of the following client statements indicates a need for further teaching regarding treatment for hypokalemia? 1. “I will use avocado in my salads.” 2. “I will be sure to check my heart rate before I take my digoxin.” 3. “I will take my potassium in the morning after eating breakfast.” 4. “I will stop using my salt substitute.”

1. An elderly nursing home resident has refused to eat or drink for several days and is admitted to the hospital. The nurse should assess for which of the following? 1. Increased blood pressure 2. Weak, rapid pulse 3. Moist mucous membranes 4. Jugular vein distention 2. A man brings his elderly wife to the emergency department. He states that she has been vomiting and has had diarrhea for the past 2 days. She appears lethargic and is complaining of leg cramps. What should the nurse do first? 1. Start an IV. 2. Review the results of serum electrolytes. 3. Offer the woman foods that are high in sodium and potassium content. 4. Administer an antiemetic.

7. An elderly man is admitted to the medical unit with a diagnosis of dehydration. Which of the following signs or symptoms are most representative of a sodium imbalance? 1. Hyperreflexia 2. Mental confusion 3. Irregular pulse 4. Muscle weakness 8. The client’s arterial blood gas results are: pH 7.32; PaCO2 58; HCO3 32. The nurse knows that the client is experiencing which acid–base imbalance? 1. Metabolic acidosis 2. Respiratory acidosis 3. Metabolic alkalosis 4. Respiratory alkalosis

3. The nurse administers an IV solution of D5 1⁄2 NS to a postoperative client. This is classified as what type of intravenous solution? ___________ 4. An older client comes to the emergency department experiencing chest pain and shortness of breath. An arterial blood gas is ordered. Which of the following ABG results indicates respiratory acidosis? 1. pH 7.54; PaCO2 28 mm Hg; HCO3 22 mEq/L 2. pH 7.32; PaCO2 46 mm Hg; HCO3 24 mEq/L 3. pH 7.31; PaCO2 35 mm Hg; HCO3 20 mEq/L 4. pH 7.50; PaCO2 37 mm Hg; HCO3 28 mEq/L 5. The intake and output (I & O) record of a client with a nasogastric tube that has been attached to suction for two (2) days shows greater output than input. Which nursing diagnoses are most applicable? Select all that apply. 1. Deficient Fluid Volume 2. Risk for Deficient Fluid Volume 3. Impaired Oral Mucous Membranes 4. Impaired Gas Exchange 5. Decreased Cardiac Output

9. A client is admitted to the hospital for hypocalcemia. Nursing interventions relating to which system would have the highest priority? 1. Renal 2. Cardiac 3. Gastrointestinal 4. Neuromuscular 10. The nurse would assess for signs of hypomagnesemia in which of the following clients? Select all that apply. 1. A client with renal failure 2. A client with pancreatitis 3. A client taking magnesium-containing antacids 4. A client with excessive nasogastric drainage 5. A client with chronic alcoholism See Answers to Test Your Knowledge in Appendix A.

EXPLORE MEDIALINK DVD-ROM ■ Audio Glossary ■ NCLEX Review ■ Skills Checklists ■ Animations: Membrane Transport Filtration Pressure Fluid Balance Acid–Base Balance Furosemide Drug Applying a Central Venous Line

www.prenhall.com/berman COMPANION WEBSITE Additional NCLEX Review Case Study: Client with Suspected Electrolyte Imbalance Care Plan Activity: Client with Heart Failure Application Activities: Determining Body Fluid Problems Arterial Blood Gases and Acid–Base Balance ■ Links to Resources ■ ■ ■ ■

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READINGS AND REFERENCES SUGGESTED READINGS Billings, D., & Kowalski, K. (2005). Do your CATS PRRR? A mnemonic device to teach safety checks for administering intravenous medications. Journal of Continuing Education in Nursing, 36(3), 104–106. The authors suggest using this mnemonic (CATS PRRR) to help nurses remember the important safety checks of IV medication administration. Having this mnemonic written on the nurse’s clipboard will help the nurse to stay focused on the task in a hectic and stressful working environment. The article explains how each letter pertains to important safety checks when administering IV medications. Davidhizar, R., Dunn, C. L., & Hart, A. N. (2004). A review of the literature on how important water is to the world’s elderly population. International Nursing Review, 51(3), 159–167. These authors discuss the importance of water to the elderly population and provide strategies to promote health related to water intake. Mentes, J. (2006). Oral hydration in older adults. American Journal of Nursing, 106(6), 40–49. This article reviews age-related changes, risk factors, assessment measures, and nursing interventions for dehydration. Rosenthal, K. (2003). Keeping I.V. therapy safe with needleless systems. Nursing, 33(10), 16–20. This article details how needleless systems reduce the health care professional’s risk of injury and exposure to bloodborne pathogens. Rosenthal, K. (2004). The new look of I.V. therapy: Improvements to existing products and technology enhance patient care, satisfaction, and outcomes. Nursing Management, 35(12), 66–70. This article provides information about the new infusion devices that are now available. This author provides information on an array of anesthetics and needleless IV devices. RELATED RESEARCH Berk, D. R., Conti, P. M., & Sommer, B. R. (2004/2005). Orange juice-induced hyperkalemia in schizophrenia. International Journal of Psychiatry in Medicine, 34(1), 79–82. Crawford, A. (2004). An audit of the patient’s experience of arterial blood gas testing. British Journal of Nursing, 13(9), 529–532. Da Silva, L. (2004). The use & abuse of parenteral nutrition: Can we change practice? Canadian Journal of Dietetic Practice and Research, 26, 3. Mentes, J. C. (2006). A typology of oral hydration: Problems exhibited by frail nursing home residents. Journal of Gerontological Nursing, 32(1), 13–19. Oh, H., Suh, Y., Hwang, S., & Seo, W. (2005). Effects of nasogastric tube feeding on serum sodium, potassium, and glucose levels. Journal of Nursing Scholarship, 37(2), 141–147. Wathen, J. E., MacKenzie, T., & Bothner, J. P. (2004). Usefulness of the serum electrolyte panel in the management of pediatric dehydration treated with intravenously administered fluids. Pediatrics, 114(5), 1227–1234. REFERENCES American Medical Association, American Nurses Association–American Nurses Foundations, Centers for Disease Control and Prevention, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Food Safety

and Inspection Service, U.S. Department of Agriculture. (2004). Diagnosis and management of foodborne illnesses: A primer for physicians and other health care professionals. Morbidity and Mortality Weekly Report, 53 (RR-4), 1–33. Andrews, M. M., & Boyle, J. S. (2003). Transcultural concepts in nursing care (4th ed.). Philadelphia: Lippincott Williams & Wilkins. Astle, S. M. (2005). Restoring electrolyte balance. RN, 68(5), 34–39. Bennett, J. A., Thomas, V., & Riegel, B. (2004). Unrecognized chronic dehydration in older adults. Examining prevalence rate and risk factors. Journal of Gerontological Nursing, 30(1), 22–28. Dochterman, J. M., & Bulechek, G. M. (Eds.). (2004). Nursing interventions classification (NIC) (4th ed.). St. Louis, MO: Mosby. Elgart, H. N. (2004). Assessment of fluids and electrolytes. AACN Clinical Issues, 15(4), 607–621. Food and Drug Administration (FDA). (2004). Bar code label requirements for human drug products and biological products. Federal Register, 69(38), 9119–9171. Hadaway, L. C. (2004). Preventing and managing peripheral extravasation. Nursing, 34(5), 66–67. Hayes, D. D. (2004). Calcium in the balance. Nursing Made Incredibly Easy, 2(2), 46–53. Masoorli, S., & Angeles, T. (2002). Getting a line on central vascular access devices. Nursing, 32(4), 36–43. Moorhead, S., Johnson, M., & Maas, M. (Eds.). (2004). Nursing outcomes classification (NOC) (3rd ed.). St. Louis, MO: Mosby. NANDA International. (2007). NANDA nursing diagnoses: Definitions and classification 2007–2008. Philadelphia: Author. Phillips, L. D. (2005). Manual of I.V. therapeutics (4th ed.). Philadelphia: F. A. Davis. Rosenthal, K. (2004). Avoiding bad blood: Key steps to safe transfusions. Nursing Made Incredibly Easy, 2(5), 20–29. Rosenthal, K. (2005a). Tailor your I.V. insertion techniques for special populations. Nursing, 35(5), 37–41. Rosenthal, K. (2005b). Ports: The gateway to central lines. Nursing Made Incredibly Easy, 3(1), 53–56. Simpson, H. (2004). Interpretation of arterial blood gases: A clinical guide for nurses. British Journal of Nursing, 13(9), 522–528. Spandorfer, P. R., Alessandrini, E. A., Joffe, M. D., Localio, R., & Shaw, K. N. (2005). Oral versus intravenous rehydration of moderately dehydrated children: A randomized, controlled trial. Pediatrics, 115(2), 295–301. Wilburn, S. Q. (2004). Needlestick and sharps injury prevention. Online Journal of Issues in Nursing, 9(3), manuscript 4. Retrieved July 15, 2006, from http://www.nursingworld.org/ojin/ topic25/tpc25_4.htm Yucha, C. (2004). Renal regulation of acid–base balance. Nephrology Nursing Journal, 31(2), 201–208. SELECTED BIBLIOGRAPHY Allen, K. (2005). Four-step method of interpreting arterial blood gas analysis. Nursing Times, 101(1), 42–45. Anderson, N. R. (2005). When to use a midline catheter. Nursing, 35(4), 28. Bunce, M. (2003). Troubleshooting central lines. RN, 66(12), 28–33.

Burger, C. M. (2004). Hyperkalemia: When serum K⫹ is not okay. American Journal of Nursing, 104(10), 66–70. Burger, C. M. (2004). Hypokalemia: Averting crisis with early recognition and intervention. American Journal of Nursing, 104(11), 61–65. Centers for Disease Control and Prevention. (2002). Guidelines for the prevention of intravascular catheter-related infections. Morbidity and Mortality Weekly Report, 51(10), 1–29. Corbett, J. V. (2004). Laboratory tests and diagnostic procedures with nursing diagnoses (6th ed.). Upper Saddle River, NJ: Pearson Prentice Hall. Deglin, J. H., & Vallerand, A. H. (2004). Davis’s drug guide for nurses (9th ed.). Philadelphia: F. A. Davis. Dulak, S. B. (2005). Technology today: Smart IV pumps. RN, 68(12), 38–43. Hadaway, L. C. (2003). Infusing without infecting. Nursing, 33(10), 58–64. Hadaway, L. C. (2005). Reopen the pipeline for I.V. therapy. Nursing, 35(8), 54–61. Hadaway, L. C. (2006). Keeping central line infection at bay. Nursing, 36(4), 58–63. Hayes, D. D. (2004). Balancing act: What happens when sodium and water are off-kilter? Nursing Made Incredibly Easy, 2(1), 52–57. Hayes, D. D. (2004). Magnesium’s balancing act. Nursing Made Incredibly Easy, 2(4), 44–50. Hayes, D. D. (2004). Phosphorus: Here, there, everywhere. Nursing Made Incredibly Easy, 2(6), 36–41. Hogan, M. A., & Wane, D. (2003). Fluids, electrolytes, & acid-base balance: Reviews & rationales. Upper Saddle River, NJ: Prentice Hall. Just the facts: Fluids & electrolytes. (2005). Philadelphia: Lippincott Williams & Wilkins. Lynes, D. (2003). Respiratory care skills: An introduction to blood gas analysis. Nursing Times, 99(11), 54–55. Pruitt, W. C., & Jacobs, M. (2004). Interpreting arterial blood gases: Easy as ABC. Nursing, 34(8), 50–53. Marders, J. (2005). Sounding the alarm for I.V. infiltration. Nursing, 35(4), 19–20. Moureau, N. L. (2003). Is your skin-prep technique up-to-date? Nursing, 33(11), 17. Moureau, N. L. (2004). Tips for inserting an I.V. in an older patient. Nursing, 34(7), 18. Newberry, N. (Ed.). (2003). Sheehy’s emergency nursing (5th ed.). St. Louis, MO: Mosby. Quillen, T. F. (2005). Myths & facts: About hypercalcemia. Nursing, 35(7), 74. Rosenthal, K. (2004). It’s not magic! The tricks to cannulating difficult veins. Nursing Made Incredibly Easy, 2(2), 4–7. Rosenthal, K. (2004). The line—for central venous access—forms here. Nursing Made Incredibly Easy, 2(5), 4–7. Rosenthal, K. (2004). What you should know about needleless I.V. systems. Nursing, 34(9), 76. Rosenthal, K. (2005). Documenting peripheral I.V. therapy. Nursing, 35(7), 28. Sweeney, J. (2005). What causes sudden hypokalemia? Nursing, 35(4), 12. Sweeney, J. (2005). What causes hyponatremia? Nursing, 35(6), 18. Trimble, T. (2003). Peripheral I.V. starts: Securing and removing the catheter. Nursing, 33(9), 26. Woodrow, P. (2004). Arterial blood gas analysis. Nursing Standard, 18(21), 45–52.