The method of surfactant administration that improves homogenous distribution of surfactant in lungs is

• A. Nebulized delivery
• B. Bolus administration
• C. Continuous infusion
• D. Topical spray

Answer: (B)

Distributing surfactant evenly throughout the lungs relies on delivering a concentrated amount into the airways so that ventilation can carry it to both central and distant alveolar regions. Giving surfactant as a single endotracheal bolus places a substantial amount directly into the trachea in one event. When followed by a brief period of positive-pressure ventilation, that bolus is swept through the airways with each breath, helping the surfactant coat the surfaces across multiple lung regions rather than settling unevenly.

In contrast, methods that rely on aerosolization or topical spreading tend to yield more variable deposition in neonates. Nebulized delivery and topical spray can produce droplets that don’t deposit uniformly in the immature, small airways, especially with very small tidal volumes and high resistance. Continuous infusion distributes the dose more slowly and may not achieve rapid, widespread coating of the alveoli, which is crucial for decreasing surface tension promptly.

So, delivering a bolus of surfactant endotracheally—and allowing ventilation to facilitate its distribution—offers the most reliable, homogeneous spread across the lungs.