title: Association of prematurity, lung disease and body size with lung volume and ventilation inhomogeneity in unsedated neonates: a multicentre study.
abstract: BACKGROUND
  Previous studies have suggested that preterm birth with or without subsequent chronic lung disease is associated with reduced functional residual capacity (FRC) and increased ventilation inhomogeneity in the neonatal period. We aimed to establish whether such findings are associated with the degree of prematurity, neonatal respiratory illness and disproportionate somatic growth.
  
  
  METHODS
  Multiple breath washout measurements using an ultrasonic flowmeter were obtained from 219 infants on 306 test occasions during the first few months of life, at three neonatal units in the UK and Australia. Tests were performed during unsedated sleep in clinically stable infants (assigned to four exclusive diagnostic categories: term controls, preterm controls, respiratory distress syndrome and chronic lung disease). The determinants of neonatal lung function were assessed using multivariable, multilevel modelling.
  
  
  RESULTS
  After adjustment for age and body proportions, the factors gestation, intrauterine growth restriction and days of supplemental oxygen were all significantly associated with a reduced FRC. In contrast, increased ventilation inhomogeneity (elevated lung clearance index) was only significantly associated with duration of supplemental oxygen. After adjusting for continuous variables, diagnostic category made no further contribution to the models. Despite using identical techniques, unexpected inter-centre differences occurred, associated with the equipment used; these did not alter the negative association of preterm delivery and disease severity with lung function outcomes.
  
  
  CONCLUSIONS
  Reduction in FRC is independently associated with prematurity, intrauterine growth restriction and severity of neonatal lung disease. Determinants of lung function shortly after birth are highly complex in different disease groups.
authors.affiliation: Portex Anaesthesia, Intensive Therapy and Respiratory Medicine Unit, UCL, Institute of Child Health and Great Ormond Street Hospital for Children NHS Trust, London, UK. g.huelskamp@clemenshospital.de
authors.forename: G
authors.initials: G
authors.lastname: Hülskamp
authors.forename: S
authors.initials: S
authors.lastname: Lum
authors.forename: J
authors.initials: J
authors.lastname: Stocks
authors.forename: A
authors.initials: A
authors.lastname: Wade
authors.forename: A F
authors.initials: AF
authors.lastname: Hoo
authors.forename: K
authors.initials: K
authors.lastname: Costeloe
authors.forename: J
authors.initials: J
authors.lastname: Hawdon
authors.forename: K
authors.initials: K
authors.lastname: Deeptha
authors.forename: J J
authors.initials: JJ
authors.lastname: Pillow
mesh_terms: D049628:Body Size / Q000502:physiology; D016022:Case-Control Studies; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000209:etiology* / Q000473:pathology; D008171:Lung Diseases / Q000473:pathology*; D009929:Organ Size / Q000502:physiology; D012120:Respiration Disorders / Q000209:etiology* / Q000473:pathology; D012129:Respiratory Function Tests