Spirometric response to bronchodilator and eucapnic voluntary hyperpnea in adults with asthma

Abstract

BACKGROUND: The spirometric response to fast-acting bronchodilator is used clinically to diagnose asthma and in clinical research to verify its presence. However, bronchodilator responsiveness does not correlate with airway hyper-responsiveness measured with the direct-acting stimulus of methacho-line, demonstrating that bronchodilator responsiveness is a problematic method for diagnosing asthma. The relationship between bronchodilator responsiveness and airway hyper-responsiveness assessed with indirect-acting stimuli is not known. METHODS: Retrospectively, the spirometric responses to inhaled bronchodilator and a eucapnic voluntary hyperpnea challenge (EVH) were compared in 39 non-smoking adult subjects with asthma (26 male, 13 female; mean 6 SD age 26.9 6 7.8 y; mean 6 SD body mass index 26.3 6 4.7 kg/m2). All subjects met one or both of 2 criteria: 6 12% and 200 mL increase in FEV1 after inhaled bronchodilator, and 6 10% decrease in FEV1 after an EVH challenge. RESULTS: Overall, FEV1 increased by 9.9 6 7.9% after bronchodilator (3.93 6 0.97 to 4.28 6 0.91 L, P