OUTREACH EDUCATION
Fluid And Electrolyte Management For Sick Kids© Wendy Murchie, RN, BSN, CCRN March 6, 2008
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Objectives
Fluid & Electrolyte Management For Sick Kids
¾ Review concepts of fluid movement and
electrolyte control ¾ Assessment and clinical presentations of fluid volume deficit & overload ¾ Electrolyte imbalances: causes and management ¾ Case Studies
Nursing Grand Rounds Spring 2008 Wendy Murchie, RN, BSN, CCRN
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
6565-80% of body weight is Water ¾ ¾
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Fluid located within cells Largest component (2/3): 42% of body weight Most stable, fairly resistant to major fluid shifts
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
Extracellular (ECF) ¾
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Consists of interstitial fluid, plasma, and transcellular water Reserve fluid. Replaces either fluid in vessels or cells.
Diffusion z
z
Osmosis z
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Movement of molecules from an area of high concentration to low concentration Electrolytes move easily
Movement of water between two compartments by a semipermeable membrane. Osmosis is the major force in body fluid movement.
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
Mechanisms Controlling Fluid and Electrolyte Movement Osmotic Pressure z Pulling force exerted by colloids in a solution. z Plasma proteins stay within the vessel and draw fluid towards them. z Water will move from less concentrated to more concentrated side. Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
Mechanisms Controlling Fluid and Electrolyte Movement
Body Water Intracellular (ICF)
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
Question… ¾ Sam is a 12 year old in septic shock. He
has a low to normal BP with the use of Dopamine and volume. Despite therapy he has severe third spacing. What would help with his blood pressure support but ALSO provide some diuresis for the third spacing? ¾ Albumin March 6, 2008
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
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Movement of Fluid between Compartments
Albumin ¾ Major plasma protein ¾ Increased albumin concentration results in
¾ Hydrostatic pressure and
osmotic pressure regulate the movement of water and electrolytes from one compartment to another.
fluid moving back into the capillaries from the interstitial space ¾ Decreased albumin concentrations results in fluid leaking into the interstitial space
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
Osmolality and Osmolarity Refers to the concentration of a solution which creates its osmotic pressure. pressure.
IV Fluids and their Influences
¾ Serum Osmo is the concentration of
particles in the plasma. z
Normal Serum Osmo: Osmo: 275275-295mOsm/L
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
Isotonic ¾ ¾ ¾
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Hypotonic
Equal osmolality as plasma It has no pulling effects (no osmotic pressure) Great for expanding the vascular volume quickly (increase BP) Examples: z Normal Saline (sodium and chloride) z Lactated Ringers (sodium, chloride, potassium, calcium, and lactate)
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Has a lower osmolality than plasma Water is pulled out of vessels into cells. Contraindicated in acute brain injuriesinjuries- will increase cerebral edema Examples: z z
z
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
March 6, 2008
D5W 0.45% and 0.225% Normal Saline D5 with normal saline
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
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Hypertonic ¾ ¾ ¾
Has a higher osmolality than plasma Water is pulled from the cells into the vessels. Specific situations of use and requires careful control of sodium and serum osmo’ osmo’s. z
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Question ¾
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z
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Intracranial hypertension 3% Saline
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
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z
Newborn 0 - 72 hrs old 6060-100 mL/kg/day
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0 - 10 kg 100100-150 mL/kg/day
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11 - 20 kg 1000 mL for 1st 10kg + 50mL/kg for each kg > 10kg
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21 - 30 kg 1500mL for 1st 20kg + 25mL/kg for each kg > 20kg
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
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March 6, 2008
A child’ child’s maintenance fluid requirement decreases proportionately with increasing age (and weight). March 6, 2008
Thoughts about Kids… ¾
Body Surface Area (BSA) Formula: 1500mL/m2 BSA/day
replaces the insensible losses (from breathing, through the skin, and in the stool), allows excretion of the daily production of excess solute load (urea, creatinine, electrolytes etc) in a volume of urine that is of an osmolarity similar to plasma.
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
Maintenance Fluid Requirements ¾
Maintenance fluid is the volume of daily fluid intake which z
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Maintenance Fluids
balance between water intake and the combined water loss from renal excretion, respiratory, skin, and GI sources.
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
Cerebral cells will absorb free water and cause increase in cerebral edema.
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
Regulation of Fluid Balance ¾ Water homeostasis results from the
Hypotonic fluids (D5W)
Why? z
Examples: z
A 16year old is in the ICU 12 hours after a bicycle collision. His CT is negative for bleeding but he remains obtunded and being observed. What IV fluids would be dangerous for this client?
The kidneys of an infant or child are functionally immature as compared to the adolescent or adult kidney. At this stage of life, the kidney is unable to concentrate or dilute urine. The kidney cannot conserve or excrete sodium or acidify urine. The kidneys of an infant or child are less efficient at excreting the metabolic wastes of metabolism. Therefore, the pediatric patient is less able to handle large amounts of solute.
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
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ADH Regulation of Water
Chemical Regulation of Water
Prolonged fever, vomiting, diarrhea.
¾ Antidiuretic hormone (ADH) from the
posterior pituitary gland causes a reduction in the amount of water lost in the urine.
È Blood Pressure È Blood Volume
Blood loss
Ç Blood Osmolality
Burns Osmoreceptors in the hypothalamus stimulate the pituitary gland to secrete ADH
Shock Vasodilation Decreased and concentrated urine (Ç SG)
ADH stimulates renal tubules to Ç reabsorption of water
ÇBlood Pressure ÇBlood volume ÇBlood osmolality Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
More on ADH ¾
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Example:
When drinking adequate water, the ADH mechanism is inhibited, and more water is expelled in the urine. ADH is inhibited with a serum osmolality of < 280mmoL Osmotic changes also stimulate the thirst mechanism. A 55-10% blood volume reduction can stimulate the release of ADH. Catecholamines and angiotensin II can modulate the release of ADH
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
March 6, 2008
¾ Diabetes Insipidus:
Deficiency of ADH due to failed synthesis or secretion by the posterior pituitary or both. z Results from pituitary and suprasellar surgery, head trauma, cerebral edema, CNS infections. So in DI, ADH is deficient and you begin to have no inhibition to water loss. Urine output is excessive (10mL/kg/hr). z
Wendy Murchie, RN, BSN Nursing Grand Rounds Teleconference Series
Syndrome of Inappropriate ADH: z z
z
is a disorder of the body’ body’s inability to secrete water. Excessive amounts of ADH can be secreted in response to stimuli such as pulmonary disease, CHF, increased LAP, PPV, chemo etc. Conditions associated with SIADH: • Meningitis • Head trauma • Cerebral tumors • Cerebral hemorrhage
• So with SIADH, too much ADH is around and you conserve water. There is a decrease in urine output. (1.030 or with DI:
