Hydrostatic and Increased Permeability Pulmonary Edema in Pregnancy

Abstract

Acute respiratory failure during pregnancy, while relatively uncommon, remains a prominent cause of maternal mortality, accounting for more than 30% of maternal deaths. Among the causes of obstetric respiratory failure, pulmonary edema presents a particular challenge to the clinician in view of its diverse potential etiologies in the setting of altered maternal cardiopulmonary physiology.

This article focuses on pulmonary edema, starting with a brief summary of maternal physiologic adaptations to pregnancy. The etiologies of pulmonary edema are grouped into two categories: those that cause edema by causing increased hydrostatic pressure and those that cause increased permeability in the pulmonary vascular and alveolar epithelial barriers, thereby allowing fluid to accumulate in the interstitial and alveolar spaces. Within these categories, factors predisposing to pulmonary edema may be specific to pregnancy, more common during pregnancy, or nonspecific. Strategies for diagnosis are discussed, with particular attention to the differentiation between hydrostatic and increased permeability edema. Management of obstetric respiratory failure due to pulmonary edema is presented, including a brief summary of important issues regarding mechanical ventilation during pregnancy.

Key Words:

pregnancy - pulmonary edema - respiratory failure