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ARF: sudden deterioration in pulmonary gas exchange = CO
2 retention & inadequate oxygenation |
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paO
2 < 60 mmHg |
(should be 80-100)
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paCO
2 60 mmHg |
(should be 35-45)
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arterial pH < 7.35
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(pts usually acidotic)
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Direct
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Indirect
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Aspiration
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Sepsis
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Pneumonia
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Burns
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Contusions/trauma
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Truama
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Upper airway
obstruction |
TRALI
|
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Toxic inhalation
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Drug reaction/OD
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SARS
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Cardiopulm. bypass
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Pancreatitis
|
|
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Multiple fractures
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Lung/bone marrow tx
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Stage 1: inc. SOB, RR, few CXR changes... within 24 hr signs of ARDS (CXR changes)
- Tachypneic, dyspneic |
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Stage 2 (Exudative): vent. required
- Address underlying issues |
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Stage 3 (Proliferative): hemodynamically unstable
- Can't maintain BP, tachy, compen. mechanisms, inflammation & cascade of events |
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Stage 4 (Fibrotic): lung fibrosis issues; vent. management issues
- Dec. compliance, stiffness |
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Type 1 - Acute Hypoxemic: abnl. transport of O
2 w/ resultant inadequate oxygenation |
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Type 2 - Hypercapnic: inadequate alveolar ventilation; marked elevation in paCO
2 |
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Type 3 - Mixed Hypoxemic-Hypercapnic: inadequate alveolar ventilation & abnormal O
2 transport - Often most common type |
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Warrants immediate intervention!
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GOALS:
Correct the cause Alleviate hypoxemia & hypercapnia |
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Altered mental status or coma
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Severe respiratory distress
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Extremely low or agonal RR (gasping)
- Cerebral issue r/t O 2 |
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Obvious respiratory muscle fatigue - r/t inc. work of breathing = mechanical vent.
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Peripheral cyanosis - fingers, lips dusky
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Impending cardiopulm. arrest - heart starts to compensate (tachy, arrythmias) cardiac arrest
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2+ of...
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Temp. > 100.4oF (38oC) or 98.6oF (36oC)
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HR > 90 bpm
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RR > 20 breaths/min or paCO
2 < 32 |
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WBC > 12,000 or < 4,000 or/ >10% bands
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Severe end of continuum
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Complex syndrome w/ high mortality risk
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Precipitated by direct or indirect lung injury
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Pathophysiology:
Lung injury Dec. blood flow to lungs (inflamm. mediators thin lung lining) Alveolar membrane damage (membranes thicken, gases can't exchange) Inc. membrane protein permeability ("Leak syndrome"; changes osmotic pressure) Interstitial & intra-alveolar edema (alveolar area flooded = pulm. edema) Further impaired oxygenation Pulm. edema Inflamm. changes can lead to fibrosis (may cause permanent lung change) |
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Symptoms can develop very quickly after lung insult
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Assessment:
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- Accessory muscle use
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- Tachypneic
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- Tachycardia
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- Restless, air hunger = change in O
2- Confusion |
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- New/worsening lung sounds (crackles, wheezes) steroids
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- Change in SpO
2 |
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- Lethargy (lose ability to protect airway)
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- Dyspnea
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- At risk for arrythmias
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- Change in renal status
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paO
2-FiO2 ratio < 200 - shunt formula; normally > 300 |
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B/L infiltrates on CXR - white out
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Elevated serum lactate levels - indicates anaerobic metabolism, tissue hypoxia
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No cariac etiology for pulm. edema
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Deterioration of ABG's despite intervention - resistant to O
2 |
|
GOALS:
- Correct the cause - Prevent further damage - Supportive care |
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Care bundles to improve outcomes
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5 P's of ARDS:
- Perfusion (max O 2 transport) - Position - Protective lung vent. - Protocol weaning - Prevent complications |
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Mechanical ventilation
|
|
Improves O
2, figures out CO2, buys time |
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Lowest FiO
2 possible, smallest TV possible |
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Modes of MV:
|
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- Volume cycled: pushes air in until preset volume delivered
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- Time cycled: pushes air in until preset time reached
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- Assist modes: pt can assist but vent can take over work of breathing
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- Pressure support: weaning mode; depends on pt's breathing (used for weaning)
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- Pressure control: preset volume (based on age, sex, height)
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- Airway Pressure-Release Ventilation (APRV)
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Weaning ASAP!
- Infection - Dependent on machine - Muscles dependent - Vent may cause trauma (barotrauma, pressure trauma) |
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Positive End Expiratory Pressure (PEEP): back pressure prevents alveolar collapse; helps to keep fluid out of alveoli
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- Inc. PEEP = inc. intrathoracic pressure dec. perfusion = dec. CO
- Affected intrathoracic pressure = organ failure |
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3 Priorities:
|
|
1) Monitor & evaluate pt response
- Vent setting, trach appropriately - Assess s/s of distress (lung sounds, chest expansion, ABC & disynchrony r/t proper setting [change vent settings]) |
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2) Manage vent safely
- Not alone, daily CXR for placement |
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3) Prevent complications
- Oral care (dec. bacteria), turn & repo. (changes lung perfusion), VAP protocol (elevate HOB >30o, aspiration precautions), DVT prophylaxis, skin care |
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Note:
- Breath sounds should be equal & symm. - Document safety, measurement |
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Proning: no shock, inc. ICP, unstable spine
|
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Pharmacotherapy:
- Antibiotics (if known microorganism) - Bronchodilators (airway patency) - Surfactant? (not really used, expensive) - Corticosteroids? (immunosuppressed, glycemic control) - Diuretics (dec. lung/general edema, watch electrolytes) - Neuromuscular blocking agents (paralytic agents, sedatives = dec. work of breathing) - Flolan? (new; inc. flow, V/Q mismatch) - Epinephrine - Low dose dopamine |
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Ex. Neuromuscular Blocking Agents - propophol, Nimbex, + inotropes
+ Inotropes: dilate vascular bed = inc. CO (dibutamine, watch for dec. BP - r/t dose; vasopressors) |
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Nutrition:
- Dec. mortality, days of not eating prophylactic enzyme release - Avoid inc. carb feeds |
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Prevent complications - VAP, SIRS, MODS, DVT, infection, skin breakdown
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ARDS
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Mechanical Vent
|
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Impaired gas exchange
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Risk for infection
|
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Dec. tissue perfusion
|
Risk for injury - r/t airway
|
|
Airway clearance
|
Risk for injury - r/t immobility
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
