Effects of combined tiotropium/olodaterol on dynamic lung hyperinflation evaluated by the incremental hyperventilation method

Abstract

Background: The effects of combined tiotropium/olodaterol (Respimat®) on airflow obstruction, lung hyperinflation, exercise tolerance, and exacerbation in chronic obstructive pulmonary disease (COPD) have been reported. However, the effects on dynamic lung hyperinflation (DLH) have not been reported. We have developed a dedicated spirometer (Spiro Sift SP-390 Rhino) to measure DLH using the metronome-paced incremental hyperventilation (MPIH) method. Aims and Objectives: This study was performed to examine whether combined tiotropium/olodaterol (Respimat®) can improve DLH assessed by the MPIH method using the dedicated spirometer, whether it can improve exercised performance in COPD. Methods: Thirty-three patients with mild to severe stable COPD were included in the study. This was a comparative study before and 8 weeks after treatment with combined tiotropium/olodaterol 5/5 μg (Respimat®) once a day. DLH was assessed by the MPIH method, with incremental hyperventilation of 30-s stepwise increments starting at the resting respiration rate (RR) and increasing to RR of 20, 30, and finally 40 using a Spiro Sift SP-390 Rhino spirometer. The primary outcome was the decrease in inspiratory capacity (IC) from that at the resting RR. Results: The decreases in IC following hyperventilation were significantly reduced after treatment. In addition, FEV1, CAT (COPD assessment test) score, and 6-minute walking distance were also significantly improved. Conclusions: Combined tiotropium/olodaterol (Respimat®) may improve DLH and exercise performance in addition to increasing FEV1 and health status in COPD.