Clinical interpretation of airway response to a bronchodilator. Epidemiologic considerations

Am Rev Respir Dis. 1988 Aug;138(2):317-20. doi: 10.1164/ajrccm/138.2.317.


Airways responsiveness to a bronchodilator is frequently measured to assist in determining the cause of respiratory symptoms. Clinically, a greater than 15% improvement in the FEV1 is often used to define the "increased" response indicative of asthma. However, unlike other tests of lung function, reference standards derived from "healthy" members of a general population sample have never been reported. As part of a health survey carried out in Alberta, Canada, 2,609 subjects completed a standardized respiratory symptom questionnaire and had FEV1 measured before and 20 min after inhaling terbutaline sulfate via a 750-ml spacer device. Among asymptomatic never-smoking subjects with a FEV1 greater than 80% of predicted, the upper 95th percentile of bronchodilator response (BDR), when expressed as 100 x (FEV1 postBDR - FEV1 preBDR)/predicted baseline FEV1 averaged 9%. This value remained remarkably stable across gender, age (7 to 75 yr), and height groups, and deviated to 6% only when baseline FEV1 was greater than 120% of predicted. Consistent with other respiratory function variables, in which the upper limit of normal is often defined as the upper 95th percentile, our population-derived reference values provide a conceptual definition of BDR that can easily be applied to define "increased" response in the clinical setting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Air Pollutants, Occupational / adverse effects
  • Bronchodilator Agents / pharmacology*
  • Child
  • Female
  • Forced Expiratory Volume*
  • Humans
  • Male
  • Middle Aged
  • Reference Values
  • Terbutaline / pharmacology


  • Air Pollutants, Occupational
  • Bronchodilator Agents
  • Terbutaline