Unilateral negative pressure pulmonary edema during anesthesia with a laryngeal mask airway

Abstract

Purpose: To present a case of unilateral pulmonary edema after upper airway obstruction. Clinical Features: In a 21-yr-old man, anesthesia was induced with propofol and maintained with N2O/O2/isoflurane via an LMA. After being placed in the lateral position, he had an episode of upper airway obstruction while breathing spontaneously. Hypoxemia (SpO2 80-83%) refractory to the administration of oxygen (F1O2 1.0) ensued following relief of the obstruction. Chest X-ray showed edema of the dependent lung. Treatment consisted of placing the patient in the sitting position and supplemental oxygen. The situation resolved over a few hours. Conclusion: If airway obstruction occurs in the lateral position, development of negative pressure pulmonary edema (NPPE) in the dependent lung is favoured by hydrostatic forces and possibly the elevated resting position of the dependent hemidiaphragm.