A systematic review and meta-analysis of the effects of respiratory muscle training on pulmonary function in tetraplegia

Study design: Systematic review Objectives: To determine the effect of respiratory muscle training (RMT) on pulmonary function in tetraplegia. Methods: A comprehensive search of the research literature included MEDLINE, EMBASE, CINAHL, ISI Web of Science, PubMed, the relevant Cochrane and clinical trials registers and hand-searching the reference lists of appropriate papers. There was no language restriction. All randomised controlled trials that involved RMT vs control were considered for inclusion. Two reviewers independently selected articles for inclusion, evaluated the methodological quality and extracted data. Additional information was sought from the authors when necessary. Results: Eleven studies (212 participants) were included. A significant benefit of RMT was revealed for five outcomes: vital capacity (mean difference (95% confidence interval)) - 0.41(0.17-0.64) l, maximal inspiratory pressure - 10.66(3.59, 17.72) cmH(2)O, maximal expiratory pressure = 10.31(2.80-17.82) cmH(2)O, maximum voluntary ventilation = 17.51(5.20, 29.81) l min(-1) and inspiratory capacity = 0.35(0.05, 0.65) l. No effect was found for total lung capacity, peak expiratory flow rate, functional residual capacity, residual volume, expiratory reserve volume or forced expiratory volume in 1 second. Conclusion: RMT increases respiratory strength, function and endurance during the period of training. Further research is needed to determine optimum dosages and duration of effect. This article is based in part on a Cochrane review published in the Cochrane Database of Systematic Reviews (CDSR) 2013, DOI: 10.1002/14651858.CD008507.pub2. Cochrane reviews are regularly updated as new evidence emerges and in response to feedback, and the CDSR should be consulted for the most recent version of the review.