Pulmonary edema complicating relief of upper airway obstruction.

Treatment by endotracheal intubation or tracheostomy in children with severe and prolonged upper airway obstruction usually results in dramatic improvement; in some rare instances, it is complicated by the development of pulmonary edema. During an eight-year period, the author observed this complication in 20 children. The mechanism of this edema is complex and not yet fully understood. In addition to hypoxia, profound hemodynamic changes occur during the inspiratory phase of the obstruction; highly negative transpulmonary pressure may lead to an increase in pulmonary blood volume and biventricular dysfunction, and possibly disruption of integrity of the pulmonary endothelium. These hemodynamic changes appear to be counterbalanced by the positive pleural and alveolar pressures and decreased venous return during the expiratory component of the obstruction. Nevertheless, when an artificial airway is inserted, this compensation is disrupted abruptly, resulting in an increase in systemic venous return and thus pulmonary edema. Although this type of edema usually is observed in cases of severe obstruction, it may go unrecognized or misdiagnosed.