title: Lung function in preschool children with a history of wheezing measured by forced oscillation and plethysmographic specific airway resistance.
abstract: BACKGROUND
  Wheezing is common in preschool children, but objective evidence for airway obstruction and its reversibility are rarely available in clinical practice. We assessed whether abnormalities of lung function and bronchodilator response can be detected in preschool children using the forced oscillation technique and measurements of specific airway resistance.
  
  
  METHODS
  Fifty-nine children with a history of wheeze and 24 healthy controls aged 3-6 years were recruited. Resistance and reactance at 6 and 8 Hz (Rrs6, Rrs8, Xrs6 and Xrs8, respectively) were measured using the forced oscillation technique and specific airway resistance was measured in a plethysmograph. z-Scores were calculated from published reference data. Tests were repeated 15 min after 400 mcg salbutamol. Bronchodilator response was expressed as the log-transformed ratio of postbronchodilator/prebronchodilator values.
  
  
  RESULTS
  Technically acceptable measurements using the forced oscillation technique were obtained in n = 77 (93%) of children and in n = 56 (68%) using plethysmography. There was no significant difference in baseline lung function or bronchodilator response, assessed by either technique, between those with a history of wheeze and healthy controls.
  
  
  CONCLUSIONS
  Measurement of lung function is feasible in preschool children, but neither of these techniques was able to identify diminished lung function or reversibility to bronchodilator in children with a history of wheeze.
authors.affiliation: Infection, Immunity & Environment Theme, Murdoch Children's Research Institute, Melbourne, VIC, Australia. jo.harrison@mcri.edu.au
authors.forename: Jo
authors.initials: J
authors.lastname: Harrison
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Gibson
authors.forename: Khrista
authors.initials: K
authors.lastname: Johnson
authors.forename: Gauharjit
authors.initials: G
authors.lastname: Singh
authors.forename: Billy
authors.initials: B
authors.lastname: Skoric
authors.forename: Sarath
authors.initials: S
authors.lastname: Ranganathan
mesh_terms: D000403:Airway Resistance / Q000187:drug effects / Q000502:physiology*; D000420:Albuterol / Q000494:pharmacology; D001249:Asthma / Q000503:physiopathology; D001993:Bronchodilator Agents / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D010991:Plethysmography; D012129:Respiratory Function Tests / Q000379:methods; D012135:Respiratory Sounds / Q000187:drug effects / Q000503:physiopathology*
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol