Pulmonary oedema associated with airway obstruction

Scott A. Lang, Peter G. Duncan, David A. E. Shephard, Hung C. Ha

The purpose of this review is to describe the pathogenesis of pulmonary oedema associated with upper airway obstruction, summarize what is known of its clinical presentation, and reflect upon its implications for the clinical management of airway obstruction. The pathogenesis of pulmonary oedema associated with upper airway obstruction is multifactorial. However, as the phrase "negative pressure pulmonary oedema" suggests, markedly negative intrapleural pressure is the dominant pathophysiological mechanism involved in the genesis of pulmonary oedema associated with upper airway obstruction. The frequency of the event is impossible to ascertain from the literature but paediatric cases requiring airway intervention for croup or epiglottitis and adults requiring airway intervention for emergence laryngospasm or upper airway tumours account for over 50 per cent of the documented cases in each age group, respectively. Individuals at risk should be observed closely while they remain at risk. The majority of cases present within minutes either of the development of acute severe upper airway obstruction or of relief of the obstruction. Resolution is typically rapid, over a period of a few hours. Rarely is anything more required for management than the maintenance of a patent airway, supplemental oxygen, and, in approximately 50 per cent of cases, mechanical ventilation and positive end-expiratory pressure.