title: Lung volume, breathing pattern and ventilation inhomogeneity in preterm and term infants.
abstract: BACKGROUND
  Morphological changes in preterm infants with bronchopulmonary dysplasia (BPD) have functional consequences on lung volume, ventilation inhomogeneity and respiratory mechanics. Although some studies have shown lower lung volumes and increased ventilation inhomogeneity in BPD infants, conflicting results exist possibly due to differences in sedation and measurement techniques.
  
  
  RESULTS
  We studied 127 infants with BPD, 58 preterm infants without BPD and 239 healthy term-born infants, at a matched post-conceptional age of 44 weeks during quiet natural sleep according to ATS/ERS standards. Lung function parameters measured were functional residual capacity (FRC) and ventilation inhomogeneity by multiple breath washout as well as tidal breathing parameters. Preterm infants with BPD had only marginally lower FRC (21.4 mL/kg) than preterm infants without BPD (23.4 mL/kg) and term-born infants (22.6 mL/kg), though there was no trend with disease severity. They also showed higher respiratory rates and lower ratios of time to peak expiratory flow and expiratory time (t(PTEF)/t(E)) than healthy preterm and term controls. These changes were related to disease severity. No differences were found for ventilation inhomogeneity.
  
  
  CONCLUSIONS
  Our results suggest that preterm infants with BPD have a high capacity to maintain functional lung volume during natural sleep. The alterations in breathing pattern with disease severity may reflect presence of adaptive mechanisms to cope with the disease process.
authors.affiliation: Division of Respiratory Medicine, Department of Paediatrics, Inselspital and University of Bern, Bern, Switzerland. philipp.latzin@insel.ch
authors.forename: Philipp
authors.initials: P
authors.lastname: Latzin
authors.forename: Stefan
authors.initials: S
authors.lastname: Roth
authors.forename: Cindy
authors.initials: C
authors.lastname: Thamrin
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: Hutten
authors.forename: Isabelle
authors.initials: I
authors.lastname: Pramana
authors.forename: Claudia E
authors.initials: CE
authors.lastname: Kuehni
authors.forename: Carmen
authors.initials: C
authors.lastname: Casaulta
authors.forename: Matthias
authors.initials: M
authors.lastname: Nelle
authors.forename: Thomas
authors.initials: T
authors.lastname: Riedel
authors.forename: Urs
authors.initials: U
authors.lastname: Frey
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008168:Lung / Q000502:physiology*; D008297:Male; D012119:Respiration; D012129:Respiratory Function Tests