- Negative-pressure pulmonary edema (NPPE) occurs after a patient makes strong inspiratory effort against a blocked airway. The negative pressure causes hydrostatic edema that can be life-threatening if not but minimized if treated early, usually resolves after 24-48 hours.
- Patients have and airway obstructive process either from an allergy, laryngospasm, trauma, and commonly in the case of hangings.