Background: In COPD patients, reversibility is currently evaluated from the changes of forced expiratory volume at 1s (δFEV1) and forced vital capacity (δFVC). By lowering peripheral airway smooth muscle tone, bronchodilators should decrease dynamic hyperinflation, gas trapping, and possibly dyspnea at rest. Hence, we hypothesize that specific airway resistance changes (δsRAW) should better characterize the acute response to bronchodilators. Methods: On two days, 60 COPD patients underwent dyspnea evaluation (VAS score) and pulmonary function testing at baseline and one hour after placebo or 300. μg indacaterol administration. Results: Spirographic and δsRAW-based criteria identified as responders 24 and 45 patients, respectively. δsRAW correlated with changes of intrathoracic gas volume (δITGV) (r=0.61; p1 correlated only with δFVC (r=0.34; p=0.008). Significant differences in terms of δITGV (p=0.002), δRV (p=0.023), and δVAS (pAW. Conclusions: In assessing the acute functional effect of bronchodilators, δsRAW-based criterion is preferable to FEV1-FVC-based criteria, being more closely related to bronchodilator-induced improvements of lung mechanics and dyspnea at rest.
- Adrenergic beta-agonists
- Respiratory function tests
- Short-term variability
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine