title: Airway resistance in children measured using the interrupter technique: reference values.
abstract: OBJECTIVE
  The interrupter technique is used for determining interrupter resistance (Rint) during quiet breathing. This noninvasive method requires minimal cooperation and can therefore be useful in evaluating airway obstruction in uncooperative children. To date, no reference values have been determined for Rint in a Brazilian population. The objective of this study was to define a prediction equation for airway resistance using the interrupter technique for healthy children aged 3-13 years.
  
  
  METHODS
  This was a prospective, cross-sectional study involving preschool and school children in Porto Alegre, Brazil, in whom Rint was measured during peak expiratory flow.
  
  
  RESULTS
  One-hundred and ninety-three children were evaluated. Univariate analysis using linear regression showed that height, weight and age correlated significantly and independently with Rint. Multiple regression with height, weight, age and gender as variables resulted in a model in which only height and weight were significant, independent predictors of Rint. Collinearity was identified among height, weight and age.
  
  
  CONCLUSIONS
  Reference values and an equation for calculating Rint in healthy children were obtained and are adjusted for height.
authors.affiliation: Universidade Luterana do Brasil, Canoas, RS, Brasil.
authors.forename: Viviane Viegas
authors.initials: VV
authors.lastname: Rech
authors.forename: Paula Cristina Vasconcellos
authors.initials: PC
authors.lastname: Vidal
authors.forename: Hilário Teixeira de
authors.initials: HT
authors.lastname: Melo Júnior
authors.forename: Renato Tetelbom
authors.initials: RT
authors.lastname: Stein
authors.forename: Paulo Márcio Condessa
authors.initials: PM
authors.lastname: Pitrez
authors.forename: Marcus Herbert
authors.initials: MH
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000402:Airway Obstruction / Q000473:pathology; D000403:Airway Resistance / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D012129:Respiratory Function Tests / Q000379:methods*