The effects of controlled breathing during pulmonary rehabilitation in patients with COPD.
BACKGROUND
Conventional pulmonary rehabilitation programs improve exercise tolerance but have no effect on pulmonary function in patients with chronic obstructive pulmonary disease (COPD). The role of controlled breathing using respiratory biofeedback during rehabilitation of patients with COPD remains unclear.


OBJECTIVES
To compare the effects of a conventional 4-week pulmonary rehabilitation program with those of rehabilitation plus controlled breathing interventions.


METHODS
A randomized controlled trial was performed. Pulmonary function (FEV1), exercise capacity (6-min walking distance, 6 MWD), health-related quality of life (chronic respiratory questionnaire, CRQ) and cardiac autonomic function (rMSSD) were evaluated.


RESULTS
Forty COPD patients (mean±SD age 66.1±6.4, FEV1 45.9±17.4% predicted) were randomized to rehabilitation (n=20) or rehabilitation plus controlled breathing (n=20). There were no statistically significant differences between the two groups regarding the change in FEV1 (mean difference -0.8% predicted, 95% CI -4.4 to 2.9% predicted, p=0.33), 6 MWD (mean difference 12.2 m, 95% CI -37.4 to 12.2 m, p=0.16), CRQ (mean difference in total score 0.2, 95% CI -0.1 to 0.4, p=0.11) and rMSSD (mean difference 2.2 ms, 95% CI -20.8 to 25.1 ms, p=0.51).


CONCLUSIONS
In patients with COPD undergoing a pulmonary rehabilitation program, controlled breathing using respiratory biofeedback has no effect on exercise capacity, pulmonary function, quality of life or cardiac autonomic function.