Background: Dynamic lung hyperinflation (DLH) following metronome-paced incremental hyperventilation (MPIH) was reported to be useful for assessment of pathophysiological impairment in patients with chronic obstructive pulmonary disease (COPD), and the effects of tiotropium and olodaterol on DLH following MPIH have not been reported. Methods: Treatment consisted of administration of tiotropium/olodaterol 5/5 μg inhalation solution (2.5/2.5 μg per actuation) using a soft-mist inhaler once a day. We compared outcomes before and after 8 weeks of treatment. The primary outcome was defined as a decrease in inspiratory capacity (IC) from rest by MPIH, which is an index of DLH. The secondary outcomes were COPD assessment test (CAT), forced expiratory volume in 1 s (FEV1), and 6-min walking distance (6MWD). In addition, we investigated whether there were correlations between changes with treatment in DLH and FEV1, 6MWD, and dyspnea. Results: Thirty-three of the 38 registered patients completed this study. Most of these 33 patients had mild to moderate COPD. Decreasing IC by MPIH was significantly reduced by treatment for 8 weeks, with a mean change of about -0.11 to -0.13 mL (P <0.05). In addition, CAT score, FEV1, and 6MWD improved with treatment (P <0.05). There were no significant correlations between changes in DLH, FEV1, 6MWD, or dyspnea with treatment. Conclusions: The results of this study showed that the combination of tiotropium and olodaterol is effective for improvement of DLH following hyperventilation.
Keywords: bronchodilator agents; dynamic lung hyperinflation; hyperventilation; olodaterol; tiotropium.