Abstract
The intricate fetal circulatory blood flow undergoes abrupt changes and restructuring at birth, allowing transition to extrauterine life and survival. In the extremely low-birth-weight newborn infant (birth weight <1000 g), these changes are affected by the immaturity of the fetal cardiovascular and pulmonary systems. The immature physiology associated with the inability to transition properly can lead to a poor prognosis and create problematic issues for the clinical management of these infants. Potentially problematic issues and complications include immature myocardium, adrenal insufficiency, patent ductus arteriosus, hypotension, and anemia. Understanding the unique transition to extrauterine life for these infants, problems that arise from immaturity and incomplete transition, and current approaches to management will help nurses and physicians caring for ELBW infants to improve the care they give and minimize mortality and morbidity in this vulnerable population. This article will review transitional physiology for term and preterm newborns, potential problems and complications, and current management approaches.