Negative pressure pulmonary edema


  • Also known as post-obstructive pulmonary edema
  • Forced inspiration against obstructed airway causes large negative intrathoracic pressure, leading to pulmonary edema[1]
  • Mostly due to postoperative laryngospasm, sudden drops in PEEP (high PEEP to manual BVM), trauma such as hanging, strangulation, foreign bodies, etc.

Clinical Features

  • Hypoxemia (may be sudden and large - beware "fake" or "not real" SpO2), stridor, retractions, accessory muscle use, crackles/wheezes
  • CXR shows diffuse interstitial and alveolar infiltrates
  • CT shows preferential central/nondependent distribution of edema (as opposed to other forms of pulmonary edema)

Differential Diagnosis

Pulmonary Edema Types

Cardiogenic pulmonary edema

Noncardiogenic pulmonary edema



  • Relieve airway obstruction
  • Vent with generous PEEP and diuretics


See Also

External Links


  1. Bhaskar B, Fraser JF. Negative pressure pulmonary edema revisited: Pathophysiology and review of management. Saudi J Anaesth. 2011 Jul-Sep; 5(3): 308–313.