Which treatment used for persistent pulmonary hypertension of the newborn (PPHN) has reduced the number of infants requiring ECMO?

• A. Alkali infusion
• B. High-frequency ventilation
• C. Extracorporeal membrane oxygenation
• D. Inhaled nitric oxide (iNO)

Answer: (D)

Inhaled nitric oxide works by selectively dilating the pulmonary vessels, which lowers pulmonary vascular resistance and improves oxygenation by reducing the right-to-left shunting that drives hypoxemia in persistent pulmonary hypertension of the newborn. Because its effect is targeted to the lungs and can rapidly improve oxygenation without causing systemic hypotension, it often eliminates the need for extracorporeal membrane oxygenation in many infants. Other approaches like alkali infusion or high-frequency ventilation support breathing but do not address the underlying pulmonary vasoconstriction as specifically, so they are less likely to reduce ECMO requirements. Monitor for potential side effects such as methemoglobinemia and ensure careful weaning to prevent rebound pulmonary hypertension.