title: Bronchodilator responsiveness using spirometry in healthy and asthmatic preschool children.
abstract: OBJECTIVE
  To assess repeatability and reproducibility of spirometry measurements, and bronchodilator responsiveness (BDR), in healthy 3-6-year-old preschool children and those with asthma.
  
  
  METHODS
  Spirometry was performed before and 20 minutes after administering either inhaled placebo (for repeatability) or 400 μg salbutamol (for BDR) on two separate occasions (reproducibility) 3-23 days apart in asthmatic preschoolers and healthy controls.
  
  
  METHODS
  Lung Function Laboratory, Hospital de Dona Estefania, Lisbon.
  
  
  METHODS
  Healthy preschool children and those with physician-diagnosed asthma, recruited from local Health Clinics and Outpatient Clinic.
  
  
  METHODS
  Paired measurements of forced expired volume in 0.75 s (FEV(0.75)) and forced mid-expiratory flows (FEF(25-75)).
  
  
  RESULTS
  Technically successful baseline results were obtained in 86% of children assessed. Paired data were obtained in 43 asthmatic and 22 controls (median (range) age: 5.1 (3.4-6.8) years). Baseline FEV(0.75) was significantly lower in asthmatic children (mean (SD): 90 (15)% predicted) than in controls (102 (13) % predicted; p<0.001). Within-occasion coefficient of repeatability following placebo was similar in both groups, being 10.4% in asthma and 13.2% in controls for FEV(0.75). Following bronchodilator, FEV(0.75) increased significantly more in asthmatic preschoolers (mean (SD): 15.0 (12) %) than in controls (4.5 (5) %; p<0.001), with no significant difference between groups post-bronchodilator. Between-occasion variability was similar to within-day repeatability in controls, but almost twice as high in asthmatic children.
  
  
  CONCLUSIONS
  BDR can be assessed reliably using FEV(0.75) in wheezy preschoolers, provided within-subject variability and responsiveness in health are taken into consideration.
authors.affiliation: Departamento de Imunologia, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo dos Mártires da Pátria 123, Lisboa 1150-227, Portugal. borregolm@gmail.com
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Borrego
authors.forename: Janet
authors.initials: J
authors.lastname: Stocks
authors.forename: Isabel
authors.initials: I
authors.lastname: Almeida
authors.forename: Sanja
authors.initials: S
authors.lastname: Stanojevic
authors.forename: João
authors.initials: J
authors.lastname: Antunes
authors.forename: Paula
authors.initials: P
authors.lastname: Leiria-Pinto
authors.forename: José E
authors.initials: JE
authors.lastname: Rosado-Pinto
authors.forename: Ah-Fong
authors.initials: AF
authors.lastname: Hoo
mesh_terms: D000420:Albuterol / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D011174:Portugal; D015203:Reproducibility of Results; D013147:Spirometry / Q000379:methods*
chemical_list: D001993:Bronchodilator Agents; D000420:Albuterol