A delay in clinical improvement from respiratory distress syndrome with prolonged need for high ventilator settings should raise suspicion for which condition?

• A. Coarctation of the aorta
• B. Intraventricular hemorrhage
• C. Pulmonary hypertension
• D. Patent ductus arteriosus

Answer: (D)

A persistent left-to-right shunt through a patent ductus arteriosus can keep pulmonary blood flow abnormally high, raising pulmonary capillary pressures and causing pulmonary edema. In a preterm infant with respiratory distress syndrome, this additional hemodynamic burden makes gas exchange harder and often leads to slower or incomplete improvement, keeping the baby on high ventilator settings longer than expected. That combination—RDS failing to improve and ongoing need for high ventilator support—points strongly to a PDA as a contributor.

Coarctation of the aorta would more likely show signs of poor systemic perfusion rather than persistent pulmonary overcirculation. Intraventricular hemorrhage would present with neurologic signs rather than a primary failure to improve oxygenation. Pulmonary hypertension can cause ventilation difficulty, but the pattern of prolonged ventilation in the setting of RDS particularly suggests a PDA-driven shuffled circulation with increased pulmonary flow.