title: Vital capacity and inspiratory capacity as additional parameters to evaluate bronchodilator response in asthmatic patients: a cross sectional study.
abstract: BACKGROUND
  Bronchodilator response in patients with asthma is evaluated based on post-bronchodilator increase in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). However, the need for additional parameters, mainly among patients with severe asthma, has already been demonstrated.
  
  
  METHODS
  The aim of this study was to evaluate the usefulness of vital capacity (VC) and inspiratory capacity (IC) to evaluate bronchodilator response in asthma patients with persistent airflow obstruction. The 43 asthma patients enrolled in the study were stratified into moderate or severe airflow obstruction groups based on baseline FEV1. All patients performed a 6-minute walk test before and after the bronchodilator (BD). A bipolar visual analogue scale post-BD was performed to assess clinical effect. The correlation between VC and IC and clinical response, determined by visual analogue scale (VAS) and 6-minute walk test (6MWT), was investigated.
  
  
  RESULTS
  Patients in the severe group presented: 1) greater bronchodilator response in VC (48% vs 15%, p = 0.02), 2) a significant correlation between VC variation and the reduction in air trapping (Rs = 0.70; p < 0.01), 3) a significant agreement between VC and VAS score (kappa = 0.57; p < 0.01). There was no correlation between IC and the reduction in air trapping or clinical data.
  
  
  CONCLUSIONS
  VC may be a useful additional parameter to evaluate bronchodilator response in asthma patients with severe airflow obstruction.
authors.affiliation: Laboratory of Pulmonary Function Tests, Institute of Thoracic Diseases, Federal University of Rio de Janeiro, Cidade Universitária, CEP 21941-913, Rio de Janeiro, Brazil. karensodre@hotmail.com
authors.forename: Karen S
authors.initials: KS
authors.lastname: Azevedo
authors.forename: Ronir R
authors.initials: RR
authors.lastname: Luiz
authors.forename: Patricia Rm
authors.initials: PR
authors.lastname: Rocco
authors.forename: Marcus B
authors.initials: MB
authors.lastname: Conde
mesh_terms: D058666:Adrenergic beta-2 Receptor Agonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology*; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D007320:Inspiratory Capacity / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D016896:Treatment Outcome; D014797:Vital Capacity / Q000502:physiology*
chemical_list: D058666:Adrenergic beta-2 Receptor Agonists; D001993:Bronchodilator Agents