Inspiratory muscle training is associated with decreased postoperative pulmonary complications: Evidence from randomized trials

Objective: To determine whether preoperative inspiratory muscle training was associated with a significant difference in the rate of postoperative pulmonary adverse outcomes in patients undergoing cardiothoracic or upper abdominal surgery using trial sequential analysis to correct for the risk of random errors. Methods: We systematically reviewed the Excerpta Medica database, PubMed, Web of Science, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Central Register of Controlled Trials for randomized controlled trials evaluating inspiratory muscle training before cardiothoracic or upper abdominal surgery. Outcome measures included postoperative pulmonary complications, length of hospital stay, maximum inspiratory pressure, and quality of life. A random-effects model was used to estimate relative risks with 95% confidence intervals (CIs). We used trial sequential analysis to calculate a diversityadjusted required information size for meta-analysis. Results: Thirteen randomized controlled trials were included in the meta-analysis for a total of 784 patients. Compared with the standard care group, the inspiratory muscle training group exhibited significantly decreased postoperative pulmonary complications (risk ratio, 0.59; 95% CI, 0.47-0.74). Trial sequential analysis indicated that the cumulative Z curve crossed both the conventional boundary and the trial sequential monitoring boundary for benefit. The length of hospital stay was reduced in the inspiratory muscle training group (mean difference, -1.15 days; 95% CI, -2.10 to 0.20), and the maximum inspiratory pressure was significantly improved at the end of the preoperative training (mean difference, 13.66; 95% CI, 3.88-23.44). The quality of life outcome was unavailable in most of the studies. Conclusions: Preoperative inspiratory muscle training resulted in significantly improved maximum inspiratory pressure and was associated with decreased postoperative pulmonary complications.