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 methacholine, 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/m 2 ). All subjects met one or both of 2 criteria: 6 12% and 200 mL increase in FEV 1 after inhaled bronchodilator, and 6 10% decrease in FEV 1 after an EVH challenge. RESULTS: Overall, FEV 1 increased by 9.9 6 7.9% after bronchodilator (3.93 6 0.97 to 4.28 6 0.91 L, P < .001) and decreased by 23.9 6 15.0% after the EVH challenge (3.89 6 0.89 to 2.96 6 0.88 L, P < .001). However, the change in FEV 1 after bronchodilator did not correlate with the change after EVH challenge (r 5 0.062, P 5 .71). Significant bronchodilator responsiveness predicted a positive response to EVH challenge in 9 of 33 subjects (sensitivity 27%). Following EVH, the change in FEV 1 strongly correlated with the change in FVC (FEV 1 percent change vs FVC percent change, r 5 0.831, P < .001; FEV 1 DL vs FVC DL, r 5 0.799, P < .001). CONCLUSIONS: These results extend previous findings that demonstrate a lack of association between bronchodilator responsiveness and methacholine responsiveness. Given the poor concordance between the spirometric response to fast-acting bronchodilator and the EVH challenge, these findings suggest that the airway response to inhaled b 2 -agonist must be interpreted with caution and in the context of its determinants and limitations.

Effect of exercise‐induced bronchoconstriction on the configuration of the maximal expiratory flow‐volume curve in adults with asthma

“…Indeed, in our subjects, the substantial decreases in FVC after exercise is compatible with this prediction (Figure 3b). Many previous studies have reported decreases in FVC after exercise or EVH in adults with asthma (Haverkamp et al, 2005;Haverkamp et al, 2021). The reduced FVC is likely due to peripheral airway inflammation and narrowing, which causes early airway closure and an accompanying increase in residual volume.…”