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-C-13(6)) glucose, we measured C-13 enrichment in surfactant phosphatidyl-choline (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 (4.70% +/- 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 = .77). 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.