Postoperative outcomes following preoperative inspiratory muscle training in patients undergoing cardiothoracic or upper abdominal surgery: a systematic review and meta analysis

Objective: To evaluate whether preoperative inspiratory muscle training is effective in preventing postoperative pulmonary complications and reducing length of hospital stay in people undergoing cardiothoracic or upper abdominal surgery. Data sources: Medline, CINAHL, AMED, PsychINFO, Scopus, PEDro, and the Cochrane Library. Review methods: A systematic review and meta analysis of randomized controlled trials (or quasi-randomized controlled trials) investigating a form of preoperative inspiratory muscle training, compared with sham or no inspiratory muscle training. Participants were adults (16years and over) awaiting elective open cardiac, thoracic, or upper abdominal surgery. Methodological quality was assessed using the PEDro scale. Results: Eight studies involving 295 participants were eligible for inclusion. The trained group had significantly higher maximal inspiratory pressure at the end of the preoperative training period (mean difference: 15cmH(2)O, 95% confidence interval (CI): 9 to 21). This benefit was maintained through the early postoperative period, when lung function also recovered significantly more quickly in the trained group. Inspiratory muscle training also substantially reduced postoperative pulmonary complications (relative risk 0.48, 95% CI 0.26 to 0.89). Although not statistically significant, length of hospital stay also tended to favour the trained group. There were no statistically significant differences between the groups for the remaining outcomes. Participant satisfaction with inspiratory muscle training was high. Conclusion: Preoperative inspiratory muscle training significantly improves respiratory (muscle) function in the early postoperative period, halving the risk of pulmonary complications. The training does not increase length of stay, but more data are required to confirm whether it reduces length of stay.