The effects of pursed lip breathing combined with diaphragmatic breathing on pulmonary function and exercise capacity in patients with COPD: a systematic review and meta-analysis.

Background: Pursed lip breathing (PLB) and diaphragmatic breathing (DB) are physical therapy interventions frequently adopted by patients with chronic obstructive pulmonary disease (COPD). This systematic review aimed to investigate the effects of PLB combined with DB on pulmonary function and exercise capacity in patients with COPD.

Methods: Six databases were searched to collect relevant studies published before August 30, 2019 in English and Chinese. Randomized controlled trials (RCTs) with PLB combined with DB training as the exclusive intervention for COPD were identified. Mean difference (MD) or standardized mean difference (SMD) with 95% confidence interval (CI) was calculated. Heterogeneity was assessed by Cochran's test and statistics.

Results: A total of 15 RCTs were included, involving 1098 patients with COPD (570 in treatment groups and 528 in control groups). Significant improvements were found in forced expiratory volume in 1 s (FEV) (SMD = 0.47, 95% CI = 0.27-0.67, < .001), forced vital capacity (FVC) (SMD = 0.87, 95% CI = 0.59-1.15, < .001), FEV as a proportion of FVC (FEV/FVC) (MD = 8.30, 95% CI = 1.17-15.43, = .02), and 6-min walk test (6MWT) distance (MD = 29.09, 95% CI = 19.35-38.83, < .001).

Conclusions: The intervention of PLB combined with DB effectively promotes pulmonary function and exercise capacity in patients with COPD. The combined application of PLB and DB is an easy and low-cost physical therapy intervention, which should be promoted as a daily essential practice of COPD.