Functional Residual Capacity (FRC) Does Not Predict Response to Surfactant in Preterm Infants

Abstract

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. FRC was measured by the helium dilution method. Arterial blood gases were measured again after 30, 60, and 120 minutes. FRC was measured after 120 minutes. Twenty-seven treatments resulted in an increase in PaO2 >10 mmHg (responders); 14 did not (nonresponders). There was no correlation between initial FRC, change in FRC, and change in PaO2 (r2 = 0.07). These results suggest that there is no relationship between initial FRC and response to surfactant treatment.

Lung Function Tests in Neonates and Infants with Chronic Lung Disease of Infancy: Functional Residual Capacity

“…This is not true for length, and gross errors in interpretation will occur if FRC is expressed per cm length, a practice that unfortunately remains all too common. 75 Length or height (measured with a calibrated stadiometer and not a tape measure!) 76 remains the best parameter to use when interpreting changes in lung volume relative to body size.…”

Lung volume and the response to high volume strategy, high frequency oscillation

“…We now report findings from a larger series of infants with RDS (n = 28). The RDS infants were all studied after surfactant administration, but the time of the measurement with respect to surfactant administration was not standardized and the response to surfactant is not predicted by the baseline FRC (14). Surfactant administration can increase lung volume (15) and this may explain the higher FRCs seen in certain of the RDS infants ( Fig.…”