Management of Patent Ductus Arteriosus (PDA) in Preterm Infants

The ductus arteriosus is a connection between the aorta and the pulmonary artery, which carries oxygenated blood from the placenta that bypasses the fetal lungs to go directly to the aorta. It stays open in fetal life because of hypoxia in utero and prostaglandin E2 (PGE2) and prostacyclin (PGI2) that are secreted from the placenta. After delivery, the duct closes within 3 days in term newborns mainly due to decrease in pulmonary pressure as a response to the increase in oxygen and decrease in prostaglandin and its receptors. In preterm infants, the duct remains open up to 7 days of age in about 87% of infants born at 24 weeks of gestation. Persistence of the ductus arteriosus, referred to often as patent ductus arteriosus (PDA), in preterm infants leads to shunting of blood from left to the right side, resulting in decrease in lung compliance, which leads to deterioration of respiratory status; this in turn causes more blood flow to the lungs, which then can lead to pulmonary edema and pulmonary hemorrhage as a consequence.