II. Epidemiology
- Occurs in 0.1% of cases of Endotracheal Intubation for General Anesthesia (esp. with laryngospasm)
- Occurs in up to 12% of patients with acute upper airway obstruction (e.g. laryngospasm)
III. Pathophysiology
- Noncardiogenic Pulmonary Edema
- Results from high negative intrathoracic pressure in the face of upper airway obstruction
- Laryngopasm during intubation or post-Anesthesia
- Intubated patients with patient Ventilator asynchrony (esp. early ARDS)
- Increased patient respiratory effort against low ventilator Tidal Volumes
- Increased pulmonary capillary bed pressure and decreased lung interstitial pressure
- Results in interstitial and alveolar fluid accumulation
- Increased adrenergic drive related to airway obstruction
- Results in increased peripheral Vasoconstriction, venous return and pulmonary capillary pressure
- High negative pressures may also disrupt the pulmonary basement membrane
- Results in increased capillary permeability and leak of Protein rich fluids into the interstitial and alveolar spaces
IV. Management
- ABC Management
- Supplemental Oxygen
- Non-Invasive Positive Pressure Ventilation (BIPAP, CPAP)
- Typically resolves within 48 hours with early recognition and treatment
-
Exercise caution with Diuretics
- Although often used in Pulmonary Edema, has little evidence in Negative Pressure Pulmonary Edema
- Risk of Hypovolemia and hypoperfusion