Biting the laryngeal mask: an unusual cause of negative pressure pulmonary edema

To describe negative pressure pulmonary edema due to biting of the laryngeal mask tube at emergence from general anesthesia.

A healthy patient underwent general anesthesia using a laryngeal mask airway and mechanical ventilation. During recovery, the patient strongly bit the laryngeal mask and made very forceful inspiratory efforts until the mask was removed. Five minutes later, the patient developed dyspnea and had an hemoptysis of 50 ml fresh blood. Chest radiograph showed bilateral alveolar infiltrates. Pharyngo-laryngeal examination was normal. Bronchoscopy revealed no injury but diffuse pink frothy edema fluid. Clinical examination and chest radiograph became normal after 12 hr of nasal oxygen therapy confirming airway obstruction as the most available cause of this pulmonary edema.

Airway obstruction due to biting of a laryngeal mask tube may result in negative pressure pulmonary edema.