Endogenous pulmonary surfactant metabolism is not affected by mode of ventilation in premature infants with respiratory distress syndrome.

OBJECTIVE

To determine if high frequency oscillatory ventilation (HFOV) decreases surfactant production in premature infants with respiratory distress syndrome (RDS).

STUDY

DESIGN

We randomized 19 infants <28 weeks of gestation to either HFOV (n = 8) or conventional ventilation (CV, n = 11) at 24 hours of life. After a 24-hour continuous infusion of uniformly labeled carbon 13 glucose (U-(13)C(6)) glucose, we measured (13)C enrichment in surfactant phosphatidylcholine (PC) in tracheal aspirate samples using gas chromatography/mass spectrometry. We calculated the fractional synthetic rate (FSR) of surfactant PC from labeled glucose and its half-life of clearance (T(1/2)).

RESULTS

FSR did not differ between groups (4.7% +/- 2.7%/day CV vs 4.2% +/- 3.1%/day HFOV, P =.7). T(1/2) was 79 +/- 18 hours in the CV group and 76 +/- 23 hours in the HFOV group (P =.7). Neither degree of ventilatory support nor supplemental oxygen exposure correlated with surfactant metabolic indices. Three of 4 infants who died from RDS within the first month of life had a shorter T(1/2) than 14 of 15 infants who survived.

CONCLUSION

Surfactant metabolism is similar in preterm infants ventilated with HFOV and CV. Shortened surfactant half-life may characterize a subset of preterm infants with lethal RDS.