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
- Mostly due to postoperative laryngospasm, sudden drops in PEEP (high PEEP to manual BVM), trauma such as hanging, strangulation, foreign bodies, etc.
- 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)
Pulmonary Edema Types
Noncardiogenic pulmonary edema
- Negative pressure pulmonary edema
- Neurogenic causes
- Iatrogenic fluid overload
- Relieve airway obstruction
- Vent with generous PEEP and diuretics
- Bhaskar B, Fraser JF. Negative pressure pulmonary edema revisited: Pathophysiology and review of management. Saudi J Anaesth. 2011 Jul-Sep; 5(3): 308–313.