Acute Respiratory Failure and Mechanical Ventilation Unit 4 – PROBLEMS OF OXYGENATION

Theory Objectives • Differentiate ABG results in terms of full and partial compensation, and mixed disturbances. • Classify acid acid--base imbalances • Differentiate selected types, modes, and associated settings of mechanical ventilation

Clinical Objectives • Verify ventilator settings, and correlate them to the patient’s condition and ABG results • Recognize potential complications associated with mechanical ventilation • Explain the weaning criteria associated with mechanical ventilation • Correlate hemodynamics responses to effects of mechanical ventilation

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Respiratory Insufficiency

• Definition • Dyspnea • Tachypnea • Confusion

Respiratory Failure • Type I • Type II

Causes of Respiratory Failure???

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Assessment of Respiratory Failure
Neurologic
Respiratory
Cardiovascular
Nutrition
Psychosocial

• • • • •

CXR PFT’s ABGs Pulse oximetry ETCO2

Interventions for Respiratory Failure • Maintain airway • Optimize oxygen delivery • Reduce oxygen demands • Treat the underlying cause • Prevent complications

Nursing Diagnoses??

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… Determining the need for…

Indications for Mechanical Ventilation

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Endotracheal Tube • Oral or Nasal Insertion • Cuffed • Sizes range from 0.5 0.5--9.5 • 2 weeks or less

High resolution upper anatomy • http://www.youtube.com/watch?v=cK8fdHH yCPY Intubation – http://www.youtube.com/watch?v=tKz2zadEX_0

• Trachea vs. esophogus – http://www.youtube.com/watch?v=J4QP http://www.youtube.com/watch?v=J4QP--l2BSnk

• Tube passing via vocal cords – http://www.youtube.com/watch?v=ooewbKWNb44

Complications caused by intubation • Upper airway trauma – Dental damage – Nasal damage – Vocal cord hematoma – Tracheal ulcers/ dilation/stenosis dilation/stenosis – Tracheoesophageal fistula

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Types of Mechanical Ventilation •Negative - pressure •Positive - pressure

Negative Pressure Ventilation • Iron lung

Cuirass

Positive Pressure Ventilators

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Ventilator Settings • Resp Rate • Vt • FiO2 • IE ratio

• Sensitivity

• Sigh

• Alarms –Apnea –Volume –Pressure

How does a Ventilator Delivers Breaths??? –Volume –Pressure –Both

Modes of Ventilation Pressure Ventilation • Advantages – Pressure limited –
risk for barotrauma

• Disadvantage – – – –

No guarantee of Vt Hypoventilation Respiratory acidosis Not as comfortable

• Uses – ARDS – NEONATES

Volume Ventilation • Advantages – Simulates natural respiration – More comfortable – Vt guaranteed delivered

• Disadvantages – Barotrauma

• Uses – Most patients – OR

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Modes of Ventilation • PC • PR – IRV • PRVC

• AC • SIMV • PSV • CPAP

Assist - Control • For clients who have weakened respiratory muscles, or when we want ventilator to perform the bulk of the work

• Preset Vt • Preset rate – Client may trigger spontaneous breath – Machine delivers preset Vt – Risk of respiratory alkalosis

SIMV • Used when we • Machine breaths want the client to – Preset Vt and rate start breathing on • Patient assisted his own breaths • Weaning mode – Patients own rate • Helps preserve and depth in respiratory between ventilator muscle tone breaths

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Pressure Support Ventilation • Provides • Preset amount of inspiratory pressure during positive inspiration pressure • ↓ WOB • No set rate • Used alone, or • No set volume with SIMV • For clients w/ stable resp status

CPAP • Positive pressure applied throughout respiratory cycle • For clients who are spontaneously breathing • Weaning mode

• Patient performs ALL the WOB • Prevents alveolar collapse • Improves oxygenation • Used with PSV – 5- 10 cm H2O

Blow--by or T Blow T--tube oxygen

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Unconventional Modes of Ventilation • Pressure limited breath delivered at set rate – Poor oxygenation • Advantage – High peak airway

• PC and PC PC--IRV • For clients with:

pressures – High inspiratory flow demands • ARDS

– PIP controlled –  barotrauma

• Disadvantage – No guaranteed tidal volume

Unconventional Modes of Ventilation • PRVC • Breaths can be ventilator or • For patients with patient initiated – High peak airway pressures • Advantage – High inspiratory flow demands • ARDS

• Pressure limited breaths delivered at set RR & set Tv

– PIP controlled –  barotrauma – Guaranteed minute ventilation

• Disadvantage – ???

Positive End Expiratory Pressure • Typically 5 – 20 cm/ H2o • Improves oxygenation • Prevents atelectasis • Adverse effects –Barotrauma –Altered hemodynamics

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Medical Management • Oxygen • Bronchodilators • Corticosteroids • Sedation / analgesics • Transfusions • Therapeutic paralysis • Nutritional support • Hemodynamic monitoring

Nursing Responsibilities • Focused Pulmonary Assessment – Mode of ventilation – Verify settings – Tolerating settings

• Maintain airway • Suction ONLY as needed • Restraints ONLY as needed • Meet Nutritional needs • Meet communication needs

Suctioning

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Suction Trap • Technique – Attach one end to suction tubing – Attach other end to suction catheter – Hold upright

Nursing Responsibilities • Monitor – Total RR – Vt – PIP – SpO2 – ETT position

• Labs/diagnostics – ABG’s – CBC – Hemodynamics – CXR

Anticipate potential complications • Dislodged ETT • Unplanned extubation • Laryngeal or tracheal injury • Impaired skin integrity • Pneumothorax • Oxygen toxicity

• Impaired gas exchange • Infection • Altered hemodynamics – ↓ CO

– ↑ pulmonary vascular resistance

• Altered nutrition

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Management of Common Ventilator Alarms Alarm

Cause

High peak pressure

Anxiety / inadequate sedation H20 in tubing Accumulation of secretions Kinks in ETT or tubing Decreased lung compliance Coughing / talking / gagging

Low pressure

Leaks in vent circuit / tubing Disconnect from

Low exhaled volume Disconnection from vent or ETT Leak in cuff Patient fatigue / in lung compliance Apnea alarm

Sedative effects Neuro impairment

Route of Bacterial Entry • Micro / macro aspiration of oropharyngeal pathogens • Leakage of secretions containing bacteria around the ET cuff (AACN, 2008)

VAP Prevention

Continous removal of subglottal secretions

Elevate HOB at 3030-45 45ºº

• Handwashing

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Continuous removal of subglottic secretions

Weaning from Mechanical Ventilation • Process where mechanical ventilation is gradually withdrawn

Factors Optimizing the Weaning Process “Fix the problem” “Determine Wean-- ability” Wean

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Wean Screen • Mentally ready to wean • Medications • Absence of factors that impair weaning – Infection – Anemia – Fever – Sleep deprivation – Pain – Abdominal distention

Wean Screen • Hemodynamically Stable • Adequate Muscle Strength – RR 5mL/kg

• Adequate O2 – PaO2 60 mm Hg on FiO2 < 50% – PaO2 / FiO2 >200 mm Hg – PEEP ≤ 5 cm H20

Weaning Intolerance Respiratory • RR > 35/ min, or ↑8 from baseline • Dyspnea / ↑WOB • Use of accessory muscles • Asynchrony • SPO2