title: Endogenous pulmonary surfactant metabolism is not affected by mode of ventilation in premature infants with respiratory distress syndrome.
abstract: OBJECTIVE
  To determine if high frequency oscillatory ventilation (HFOV) decreases surfactant production in premature infants with respiratory distress syndrome (RDS).
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: the Edward Mallinckrodt Department of Pediatrics, Washington University School of Medicine, and St. Louis Children's Hospital, St Louis, Missouri 63110, USA.
authors.forename: Assaad
authors.initials: A
authors.lastname: Merchak
authors.forename: Daphne J
authors.initials: DJ
authors.lastname: Janssen
authors.forename: Kajsa
authors.initials: K
authors.lastname: Bohlin
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Patterson
authors.forename: Luc J
authors.initials: LJ
authors.lastname: Zimmermann
authors.forename: Virgilio P
authors.initials: VP
authors.lastname: Carnielli
authors.forename: Aaron
authors.initials: A
authors.lastname: Hamvas
mesh_terms: D001826:Body Fluids / Q000737:chemistry; D005260:Female; D006612:High-Frequency Ventilation; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D010713:Phosphatidylcholines / Q000032:analysis; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012121:Respiration, Artificial; D012127:Respiratory Distress Syndrome, Newborn / Q000378:metabolism* / Q000628:therapy*
chemical_list: D010713:Phosphatidylcholines; D011663:Pulmonary Surfactants