title: Membrane and Capillary Components of Lung Diffusion in Infants with Bronchopulmonary Dysplasia.
abstract: BACKGROUND
  Autopsied lungs of infants with bronchopulmonary dysplasia (BPD) demonstrate impaired alveolar development with larger and fewer alveoli, which is consistent with our previous physiologic findings of lower pulmonary diffusing capacity of the lung for carbon monoxide (DL(CO)) in infants and toddlers with BPD compared with healthy controls born at full term (FT). However, it is not known whether the decreased DL(CO) in infants with BPD results from a reduction in both components of DL(CO): pulmonary membrane diffusing capacity (D(M)) and Vc.
  
  
  OBJECTIVE
  We hypothesized that impairment of alveolar development in BPD results in a decrease in both D(M) and Vc components of DlCO but that the D(M)/Vc ratio would not differ between the BPD and FT groups.
  
  
  METHODS
  DL(CO) was measured under conditions of room air and high inspired oxygen (90%), which enabled D(M) and Vc to be calculated.
  
  
  RESULTS
  D(M) and Vc increased with increasing body length; however, infants with BPD had significantly lower D(M) and Vc than FT subjects after adjustment for race, sex, body length, and corrected age. In contrast to D(M) and Vc, the D(M)/Vc ratio remained constant with increasing body length and did not differ for infants with BPD and FT subjects.
  
  
  CONCLUSIONS
  Our findings are consistent with infants with BPD having impaired alveolar development with fewer but larger alveoli, as well as a reduced Vc.
authors.affiliation: Department of Pediatric Pulmonology, James Whitcomb Riley Hospital for Children at Indiana University, Indianapolis, Indiana.
authors.forename: Daniel V
authors.initials: DV
authors.lastname: Chang
authors.affiliation: Department of Pediatric Pulmonology, James Whitcomb Riley Hospital for Children at Indiana University, Indianapolis, Indiana.
authors.forename: Santiago J
authors.initials: SJ
authors.lastname: Assaf
authors.affiliation: Department of Pediatric Pulmonology, James Whitcomb Riley Hospital for Children at Indiana University, Indianapolis, Indiana.
authors.forename: Christina J
authors.initials: CJ
authors.lastname: Tiller
authors.affiliation: Department of Pediatric Pulmonology, James Whitcomb Riley Hospital for Children at Indiana University, Indianapolis, Indiana.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Kisling
authors.affiliation: Department of Pediatric Pulmonology, James Whitcomb Riley Hospital for Children at Indiana University, Indianapolis, Indiana.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Tepper
mesh_terms: D001810:Blood Volume; D001997:Bronchopulmonary Dysplasia / Q000473:pathology / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007196:Indiana; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D008297:Male; D011650:Pulmonary Alveoli / Q000254:growth & development / Q000473:pathology*; D011653:Pulmonary Diffusing Capacity / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology*
keywords: bronchopulmonary dysplasia; infants; lung growth; pulmonary diffusion capacity