title: Surfactant kinetics in preterm infants on mechanical ventilation who did and did not develop bronchopulmonary dysplasia.
abstract: OBJECTIVE
  To characterize surfactant kinetics in vivo in two groups of premature infants on different levels of mechanical ventilation and at different risk of developing bronchopulmonary dysplasia.
  
  
  METHODS
  Controlled observational study in two independent groups of infants.
  
  
  METHODS
  Neonatal intensive care unit.
  
  
  METHODS
  Thirteen preterm infants (26 +/- 0.5 wks, birth weight 801 +/- 64 g) on high ventilatory setting and who finally all developed bronchopulmonary dysplasia (MechVentBPD), and eight (26 +/- 0.5 wks, birth weight 887 +/- 103 g) who had minimal or no lung disease and of whom none developed bronchopulmonary dysplasia (MechVentNoBPD).
  
  
  RESULTS
  Endotracheal 13C-labeled dipalmitoyl-phosphatidylcholine was administered and subsequent measurements of the 13C enrichment of surfactant-disaturated phosphatidylcholine (DSPC) from serial tracheal aspirates were made by gas chromatography-mass spectrometry. We calculated disaturated phosphatidylcholine pharmacokinetic variables in terms of half-life and apparent pool size from the enrichment decay curves over time. DSPC concentration from tracheal aspirates was expressed as milligrams/milliliter epithelial lining fluid (ELF-DSPC). Data are presented as mean +/- se. In MechVentBPD infants vs. MechVentNoBPD, ELF-DSPC was much reduced, 2.9 +/- 0.6 vs. 9.4 +/- 3.0 mg/mL ELF (p =.03), half-life was shorter, 19.4 +/- 2.8 vs. 42.5 +/- 6.3 hrs (p =.002), and apparent pool size larger, 136 +/- 21 vs. 65.8 +/- 16.0 mg/kg (p =.057). In MechVentBPD, apparent DSPC pool size positively correlated with mean airway pressure x Fio(2) and inversely correlated with ELF-DSPC. ELF-DSPC was inversely correlated with mean airway pressure x Fio(2). No significant correlations were found in the MechVentNoBPD group.
  
  
  CONCLUSIONS
  MechVentBPD infants showed profound alteration of surfactant kinetics compared with preterm infants with minimal lung disease, and these alterations were correlated with severity of ventilatory support.
authors.affiliation: Department of Pediatrics, University of Padova, Italy.
authors.forename: Paola E
authors.initials: PE
authors.lastname: Cogo
authors.forename: Luc J I
authors.initials: LJ
authors.lastname: Zimmermann
authors.forename: Roberta
authors.initials: R
authors.lastname: Pesavento
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Sacchetto
authors.forename: Aldo
authors.initials: A
authors.lastname: Burighel
authors.forename: Federica
authors.initials: F
authors.lastname: Rosso
authors.forename: Tamara
authors.initials: T
authors.lastname: Badon
authors.forename: Giovanna
authors.initials: G
authors.lastname: Verlato
authors.forename: Virgilio P
authors.initials: VP
authors.lastname: Carnielli
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000008:administration & dosage / Q000493:pharmacokinetics; D000403:Airway Resistance; D001724:Birth Weight; D001997:Bronchopulmonary Dysplasia / Q000145:classification / Q000209:etiology* / Q000378:metabolism* / Q000503:physiopathology; D002247:Carbon Isotopes / Q000032:analysis / Q000493:pharmacokinetics; D016022:Case-Control Studies; D008401:Gas Chromatography-Mass Spectrometry; D005865:Gestational Age; D006207:Half-Life; D006801:Humans; D007231:Infant, Newborn; D007322:Instillation, Drug; D010713:Phosphatidylcholines / Q000032:analysis; D011312:Pressure; D011663:Pulmonary Surfactants / Q000378:metabolism*; D012044:Regression Analysis; D012121:Respiration, Artificial / Q000009:adverse effects*; D012307:Risk Factors; D012720:Severity of Illness Index; D013183:Sputum / Q000737:chemistry; D013997:Time Factors
chemical_list: D002247:Carbon Isotopes; D010713:Phosphatidylcholines; D011663:Pulmonary Surfactants; D015060:1,2-Dipalmitoylphosphatidylcholine