The effects of five days of intensive preoperative inspiratory muscle training on postoperative complications and outcome in patients having cardiac surgery: a randomized controlled trial

Objective: To determine the prophylactic efficacy of short-term intensive preoperative inspiratory muscle training on the incidence of postoperative pulmonary complications in patients scheduled for cardiac surgery. Design: Single-blind, randomized controlled pilot study. Setting: TEDA International Cardiovascular Hospital, China. Subjects: In total, 197 subjects aged > 50 years scheduled for cardiac surgery were selected. Intervention: The intervention group (n = 98) received five days of preoperative inspiratory muscle training on top of the usual care received by the patients in the control group (n = 99). Main measures: The primary outcome variable was the occurrence of postoperative pulmonary complications. The secondary outcome variables were inspiratory muscle strength, lung function and length of hospitalization. Results: After cardiac surgery, a total of 10 (10.2%) of the 98 patients in the intervention group and 27 (27.3%) of 99 patients in the control group had postoperative pulmonary complications (risk ratio, 0.23; 95% confidence interval (CI), 0.09-0.58, P = 0.002). The study revealed that, compared with the control group, the intervention group had a significant increase in inspiratory muscle strength (by 10.48 cm H2O, P < 0.001), forced expiratory volume in the first second of expiration (FEV1) %predicted (by 3.75%, P = 0.030), forced vital capacity (FVC) %predicted (by 4.15%, P = 0.008) and maximal voluntary ventilation (MVV) %predicted (by 6.44%, P = 0.034). Length of hospital stay was 7.51 (2.83) days in the intervention group and 9.38 (3.10) days in the control group (P = 0.039). Conclusion: A five-day intensive pattern of preoperative inspiratory muscle training reduced the incidence of postoperative pulmonary complications and duration of postoperative hospitalization in patients undergoing cardiac surgery.