Which treatment strategy is used to manage PPHN?

• A. Mechanical hyperventilation to maintain PaCO2 20-25 mmHg with alkaline pH
• B. Administration of high-frequency ventilation only
• C. Immediate surgical intervention
• D. Withhold oxygen to avoid oxygen toxicity

Answer: (A)

In PPHN the goal is to lower pulmonary vascular resistance and improve oxygenation by optimizing ventilation and acid-base status. Deliberately lowering PaCO2 with controlled mechanical hyperventilation creates respiratory alkalosis, which causes pulmonary vasodilation. This reduces the high pulmonary pressures that drive the right-to-left shunt, improves blood flow to the lungs, and enhances oxygenation. Although modern practice incorporates other therapies (like inhaled nitric oxide or ECMO for severe cases), producing a mild alkalemia via hyperventilation tackles the hemodynamic issue directly, making it the most effective choice here. Withholding oxygen would worsen hypoxemia and vasoconstriction, and relying on ventilation alone without addressing the acid-base state or using only high-frequency ventilation doesn’t target the same mechanism of reducing PVR. Immediate surgery is not indicated for PPHN.