II. Epidemiology

  1. Occurs in 0.1% of cases of Endotracheal Intubation for General Anesthesia (esp. with laryngospasm)
  2. Occurs in up to 12% of patients with acute upper airway obstruction (e.g. laryngospasm)

III. Pathophysiology

  1. Noncardiogenic Pulmonary Edema
  2. Results from high negative intrathoracic pressure in the face of upper airway obstruction
    1. Laryngopasm during intubation or post-Anesthesia
    2. Intubated patients with patient Ventilator asynchrony (esp. early ARDS)
      1. Increased patient respiratory effort against low ventilator Tidal Volumes
  3. Increased pulmonary capillary bed pressure and decreased lung interstitial pressure
    1. Results in interstitial and alveolar fluid accumulation
  4. Increased adrenergic drive related to airway obstruction
    1. Results in increased peripheral Vasoconstriction, venous return and pulmonary capillary pressure
  5. High negative pressures may also disrupt the pulmonary basement membrane
    1. Results in increased capillary permeability and leak of Protein rich fluids into the interstitial and alveolar spaces

IV. Management

  1. ABC Management
  2. Supplemental Oxygen
  3. Non-Invasive Positive Pressure Ventilation (BIPAP, CPAP)
  4. Typically resolves within 48 hours with early recognition and treatment
  5. Exercise caution with Diuretics
    1. Although often used in Pulmonary Edema, has little evidence in Negative Pressure Pulmonary Edema
    2. Risk of Hypovolemia and hypoperfusion

Images: Related links to external sites (from Bing)

Related Studies