[Negative pressure pulmonary edema: report of case series and review of the literature]

Abstract

Background and objectives: Negative pressure pulmonary edema occurs by increased intrathoracic negative pressure following inspiration against obstructed upper airway. The pressure generated is transmitted to the pulmonary capillaries and exceeds the pressure of hydrostatic equilibrium, causing fluid extravasation into the pulmonary parenchyma and alveoli. In anesthesiology, common situations such as laryngospasm and upper airway obstruction can trigger this complication, which presents considerable morbidity and requires immediate diagnosis and propaedeutics. Upper airway patency, noninvasive ventilation with positive pressure, supplemental oxygen and, if necessary, reintubation with mechanical ventilation are the basis of therapy.

Case report: Case 1: Male, 52 years old, undergoing appendectomy under general anesthesia with orotracheal intubation, non-depolarizing neuromuscular blocker, reversed with anticholinesterase, presented with laryngospasm after extubation, followed by pulmonary edema. Case 2: Female, 23 years old, undergoing breast reduction under general anesthesia with orotracheal intubation, non-depolarizing neuromuscular blocker, reversed with anticholinesterase, presented with inspiration against closed glottis after extubation, was treated with non-invasive ventilation with positive pressure; after 1 hour, she had pulmonary edema. Case 3: Male, 44 years old, undergoing ureterolithotripsy under general anesthesia, without neuromuscular blocker, presented with laryngospasm after laryngeal mask removal evolving with pulmonary edema. Case 4: Male, 7 years old, undergoing crude fracture reduction under general anesthesia with orotracheal intubation, non-depolarizing neuromuscular blocker, presented with laryngospasm reversed with non-invasive ventilation with positive pressure after extubation, followed by pulmonary edema.

Conclusions: The anesthesiologists should prevent the patient from perform a forced inspiration against closed glottis, in addition to being able to recognize and treat cases of negative pressure pulmonary edema.

Keywords: Airway obstruction; Anestesia geral; Edema pulmonar; Edema pulmonar por pressão negativa; General anesthesia; Negative pressure; Negative pressure pulmonary edema; Obstrução de vias aéreas; Pressão negativa; Pulmonary edema.