Patent ductus arteriosus in the preterm infant.

The ductus arteriosus is a communication between the main pulmonary trunk and the descending aorta. In utero, the ductus arteriosus allows blood flow to be diverted from the high-resistance pulmonary circulation to the descending aorta and the low-resistance placental bed. Functional closure of the ductus arteriosus occurs soon after birth but can be delayed in premature infants and in certain situations. Patency of the ductus arteriosus results in alterations in blood flow to many different organ systems. This article describes the physiologic effects, as well as symptoms, diagnosis, and management of a patent ductus arteriosus in the preterm infant.