title: Early detection of cystic fibrosis lung disease: multiple-breath washout versus raised volume tests.
abstract: BACKGROUND
  Lung clearance index (LCI), a measure of ventilation inhomogeneity derived from the multiple-breath inert gas washout (MBW) technique, has been shown to detect abnormal lung function more readily than spirometry in preschool children with cystic fibrosis, but whether this holds true during infancy is unknown.
  
  
  OBJECTIVE
  To compare the extent to which parameters derived from the MBW and the raised lung volume rapid thoraco-abdominal compression (RVRTC) techniques identify diminished airway function in infants with cystic fibrosis when compared with healthy controls.
  
  
  METHODS
  Measurements were performed during quiet sleep, with the tidal breathing MBW technique being performed before the forced expiratory manoeuvres.
  
  
  RESULTS
  Measurements were obtained in 39 infants with cystic fibrosis (mean (SD) age 41.4 (22.0) weeks) and 21 controls (37.0 (15.1) weeks). Infants with cystic fibrosis had a significantly higher respiratory rate (38 (10) vs 32 (5) bpm) and LCI (8.4 (1.5) vs 7.2 (0.3)), and significantly lower values for all forced expiratory flow-volume parameters compared with controls. Girls with cystic fibrosis had significantly lower forced expiratory volume (FEV(0.5) and FEF(25-75 )) than boys (mean (95% CI girls-boys): -1.2 (-2.1 to -0.3) for FEV(0.5) Z score; FEF(25-75): -1.2 (-2.2 to -0.15)). When using both the MBW and RVRTC techniques, abnormalities were detected in 72% of the infants with cystic fibrosis, with abnormalities detected in 41% using both techniques and a further 15% by each of the two tests performed.
  
  
  CONCLUSIONS
  These findings support the view that inflammatory and/or structural changes in the airways of children with cystic fibrosis start early in life, and have important implications regarding early detection and interventions. Monitoring of early lung disease and functional status in infants and young children with cystic fibrosis may be enhanced by using both MBW and the RVRTC.
authors.affiliation: Portex Anaesthesia, Intensive Therapy and Respiratory Medicine Unit, UCL, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. s.lum@ich.ucl.ac.uk
authors.forename: Sooky
authors.initials: S
authors.lastname: Lum
authors.forename: Per
authors.initials: P
authors.lastname: Gustafsson
authors.forename: Henrik
authors.initials: H
authors.lastname: Ljungberg
authors.forename: Georg
authors.initials: G
authors.lastname: Hülskamp
authors.forename: Andrew
authors.initials: A
authors.lastname: Bush
authors.forename: Siobhán B
authors.initials: SB
authors.lastname: Carr
authors.forename: Rosemary
authors.initials: R
authors.lastname: Castle
authors.forename: Ah-Fong
authors.initials: AF
authors.lastname: Hoo
authors.forename: John
authors.initials: J
authors.lastname: Price
authors.forename: Sarath
authors.initials: S
authors.lastname: Ranganathan
authors.forename: John
authors.initials: J
authors.lastname: Stroobant
authors.forename: Angie
authors.initials: A
authors.lastname: Wade
authors.forename: Colin
authors.initials: C
authors.lastname: Wallis
authors.forename: Hilary
authors.initials: H
authors.lastname: Wyatt
authors.forename: Janet
authors.initials: J
authors.lastname: Stocks
mesh_terms: D019540:Area Under Curve; D001982:Bronchial Diseases / Q000503:physiopathology; D003550:Cystic Fibrosis / Q000175:diagnosis* / Q000503:physiopathology; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D012129:Respiratory Function Tests / Q000379:methods