The ductus arteriosus is a normal blood vessel in a fetus that diverts blood flow away from the lungs. The DA usually closes on its own shortly after birth because the newborn can breathe on his or her own. If the DA doesn’t close, this is called patent ductus arteriosus (PDA),which can result in too much blood flow to a newborn’s lungs. PDA is common in premature babies.
PDA is usually diagnosed using non-invasive techniques. Echocardiography, in which sound waves are used to capture the motion of the heart, and associated Doppler studies are the primary methods of detecting PDA. A chest X-ray may be taken, which reveals the overall size of neonate’s heart and the appearance of the blood flow to the lungs. A small PDA most often shows a normal sized heart and normal blood flow to the lungs. A large PDA generally shows an enlarged cardiac silhouette and increased blood flow to the lungs.