Which agent should not be administered to a neonate with a ductal dependent lesion?

• A. Indomethacin
• B. Prostaglandin
• C. Surfactant
• D. Nitric oxide

Answer: (A)

Keeping the ductus arteriosus open is essential when a neonate has a ductal dependent lesion because the abnormal circulation relies on that connection for adequate blood flow. Prostaglandin E1 is used to maintain patency by relaxing the ductal smooth muscle. Indomethacin works differently: it inhibits prostaglandin synthesis, which leads to closure of the ductus arteriosus. Closing the ductus in a ductal dependent lesion can severely compromise systemic or pulmonary perfusion and worsen the patient’s condition. Surfactant helps with lung mechanics but doesn’t affect the ductus arteriosus, so it doesn’t address the fundamental issue. Nitric oxide reduces pulmonary vascular resistance and can aid gas exchange in certain lung conditions, but it does not preserve ductal patency. Therefore, indomethacin should not be administered in this scenario.