Functional residual capacity (FRC) does not predict response to surfactant in preterm infants.

We tested the hypothesis that the initial functional residual capacity (FRC) of preterm infants with hyaline membrane disease (HMD) could predict the response to surfactant replacement (Survanta, 4 mL/kg/dose), with a better initial FRC being correlated with a greater improvement in PaO2, a/A PO2 ratio, and FRC. Thirty-four preterm infants were studied on 41 occasions. FRC and arterial blood gases were measured immediately prior to treatment.