A premature infant with IRDS received a single dose of exogenous surfactant. An initial positive response has not been sustained. The neonatal/pediatric specialist should

• A. Recommend ECMO
• B. Re-administer the medication
• C. Increase the FiO2
• D. Initiate prone positioning

Answer: (B)

The main idea here is that surfactant therapy can require more than one dose in respiratory distress syndrome. A single exogenous surfactant dose may improve lung function initially, but as the disease process evolves, the benefit can wane if some alveoli remain collapsed or if distribution was incomplete. In that situation, the best next step is to re-administer surfactant. A second dose can re-open more alveoli, improve lung compliance, and reduce intrapulmonary shunt, helping oxygenation without waiting for a change in ventilation strategy or escalating to advanced therapies.

Increasing FiO2 alone addresses oxygen delivery but not the underlying deficiency in surfactant and carries risks of oxygen toxicity if used at high levels for prolonged periods. Initiating prone positioning may help some infants by improving ventilation distribution, but it is not a definitive corrective measure for surfactant deficiency and is not as directly impactful as giving additional surfactant. ECMO is a rescue therapy for the most severe, refractory cases after maximizing conventional supportive care; it is not the immediate next step when a second dose of surfactant is clearly indicated and feasible.