Alveolar fluid clearance in developing lungs and its role in neonatal transition

This article reviews the process of alveolar fluid clearance at birth and i ts relevance to successful transition from placental to pulmonary gas excha nge. Although mechanical factors contribute to the fluid shift from develop ing air spaces, the bulk of fluid movement is secondary to transepithelial sodium reabsorption through amiloride sensitive sodium channels. Disruption s of this process can lead to retention of fluid in the air spaces resultin g in "wet lungs" and may play a role in the pathogenesis of diseases like h yaline membrane disease and transient tachypnea of the newborn. The kev fac tors that stimulate lung fluid clearance in the perinatal period are also d iscussed.