title: Relative ability of full and partial forced expiratory maneuvers to identify diminished airway function in infants with cystic fibrosis.
abstract: The tidal and raised volume rapid thoracoabdominal compression techniques are increasingly used to detect diminished airway function in infancy. The aim of this study was to assess the relative ability of parameters measured by these techniques to identify diminished airway function in infants newly diagnosed with cystic fibrosis (CF) with and without clinical evidence of prior lower respiratory illness. A cross-sectional, prospective study design was used in which maximal flow at functional residual capacity (VmaxFRC) from the tidal technique and FVC, FEV0.5, FEF75, and FEF25-75 from the raised volume technique were measured in 47 infants with CF and 187 healthy infants of similar body size, sex distribution, ethnic group, and exposure to maternal smoking. Multiple linear regression was used to assess group differences and to calculate SD scores for each parameter for the infants with CF. Airway function was also compared with clinical assessments of respiratory status made by pediatric pulmonologists. FEV0.5 was significantly diminished in 13 infants with CF, of whom 4 had been identified by clinicians as having normal respiratory status. Only one infant with CF had a VmaxFRC below the estimated normal range. Airway function is diminished in infants with CF irrespective of prior lower respiratory illness and in those whose respiratory status is considered normal by pediatric pulmonologists. In infants with CF, the raised volume technique identified diminished airway function more frequently than the tidal technique.
authors.affiliation: Portex Anaesthesia, Intensive Therapy and Respiratory Medicine Unit, Institute of Child Health, London, United Kingdom. drsarath@clara.net
authors.forename: Sarath C
authors.initials: SC
authors.lastname: Ranganathan
authors.forename: Andrew
authors.initials: A
authors.lastname: Bush
authors.forename: Carol
authors.initials: C
authors.lastname: Dezateux
authors.forename: Siobhan B
authors.initials: SB
authors.lastname: Carr
authors.forename: Ah-Fong
authors.initials: AF
authors.lastname: Hoo
authors.forename: Sooky
authors.initials: S
authors.lastname: Lum
authors.forename: Su
authors.initials: S
authors.lastname: Madge
authors.forename: John
authors.initials: J
authors.lastname: Price
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: D000367:Age Factors; D002669:Child Welfare; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000150:complications / Q000382:microbiology / Q000503:physiopathology*; D005260:Female; D005540:Forced Expiratory Flow Rates / Q000502:physiology*; D005541:Forced Expiratory Volume / Q000502:physiology*; D005652:Functional Residual Capacity / Q000502:physiology; D006801:Humans; D007223:Infant; D007229:Infant Welfare; D007231:Infant, Newborn; D008131:London; D008297:Male; D012008:Recurrence; D012129:Respiratory Function Tests; D012141:Respiratory Tract Infections / Q000150:complications / Q000382:microbiology / Q000503:physiopathology; D014797:Vital Capacity / Q000502:physiology