Patent Ductus Arteriosus (PDA)


The ductus is normally open in utero but will close in 1-2 days after birth in response to the decreased pulmonary resistance. If the pulmonary resistance remains high then the ductus may remain open with a right to left shunt. During the first week of life, as the ventilatory therapy decreases the pulmonary resistance, the ductus may switch to a left to right shunt resulting in increased pulmonary blood flow. This is demonstrated on CXR by increased heart size and increased pulmonary vascularity. An echo will confirm the PDA.

PDA is treated with indomethacin, which inhibits prostaglandins. The PDA can be induced to remain open in cases of congenital heart disease with the administration of prostaglandins. If indomethacin does not work, then surgical ligation is necessary.

CXR shows an enlarged heart and significant vascular congestion with a
pulmonary edema pattern resulting from a PDA