Transient tachypnea of the newborn.

product/device. Introduction The birth of a child is preceded by several changes to prepare for the transition from intrauterine to extrauterine life. The five major events that establish the lungs as the organ of gas exchange at birth include: clearance of fetal lung fluid, establishment of spontaneous breathing, decrease in pulmonary vascular resistance, release of surfactant, and cessation of the right-to-left shunting of venous blood returning to the heart. (1) During fetal life, fluid is secreted into the alveoli to maintain normal growth and function, (2) and fetal lung volume approximates the functional residual capacity that would be established once air breathing is initiated. (3) Clearance of lung fluid can be affected by several factors, and its impairment culminates in tachypnea and could necessitate transfer to an intensive care unit for monitoring and respiratory support. Transient tachypnea of the newborn (TTN), which is believed to result from incomplete resorption of fluid from the lungs of the newborn, presents an important diagnostic and therapeutic dilemma in the newborn nursery. This review focuses on TTN, with emphasis on fetal lung fluid mechanics and possible mechanisms of fetal lung fluid resorption as well as its pathophysiology, clinical and diagnostic features, and management. Some neonatologists refer to TTN as retained fetal lung liquid syndrome.