Meconium’s effect on surfactant in MAS is best described by which statement?

• A. Increases synthesis of endogenous surfactant
• B. Decreases synthesis and activity of endogenous surfactant
• C. Has no effect on surfactant
• D. Increases surfactant activity

Answer: (B)

Meconium exposure in MAS disrupts surfactant by both inactivating it and reducing its production. Meconium acts like a detergent, damaging and inactivating the surface-active phospholipids that keep alveoli open, and it irritates the alveolar epithelium. This inflammatory milieu also harms type II pneumocytes, the cells that synthesize and secrete surfactant, leading to decreased synthesis and release. The net result is lower functional surfactant and impaired surfactant activity, contributing to atelectasis and decreased lung compliance.

That’s why the statement describing a decrease in both synthesis and activity of endogenous surfactant fits MAS best. It would not be correct to say it increases synthesis or activity, nor that it has no effect, given the established inactivation and impaired production seen with meconium in the lungs.