Effect of preoperative inspiratory muscle training on postoperative outcomes in patients undergoing cardiac surgery: A systematic review and meta-analysis

BACKGROUND Cardiovascular disease is the most prevalent disease worldwide and places a great burden on the health and economic welfare of patients. Cardiac surgery is an important way to treat cardiovascular disease, but it can prolong mechanical ventilation time, intensive care unit (ICU) stay, and postoperative hospitalization for patients. Previous studies have demonstrated that preoperative inspiratory muscle training could decrease the incidence of postoperative pulmonary complications. AIM To explore the effect of preoperative inspiratory muscle training on mechanical ventilation time, length of ICU stay, and duration of postoperative hospitalization after cardiac surgery. METHODS A literature search of PubMed, Web of Science, Cochrane Library, EMBASE, China National Knowledge Infrastructure, WanFang, and the China Science and Technology journal VIP database was performed on April 13, 2022. The data was independently extracted by two authors. The inclusion criteria were: ( 1) Randomized controlled trial; (2) Accessible as a full paper; (3) Patients who received cardiac surgery; ( 4) Preoperative inspiratory muscle training was implemented in these patients; ( 5) The study reported at least one of the following: Mechanical ventilation time, length of ICU stay, and/or duration of postoperative hospitalization; and (6) In English language. RESULTS We analyzed six randomized controlled trials with a total of 925 participants. The pooled mean difference of mechanical ventilation time was -0.45 h [95% confidence interval (CI): -1.59-0.69], which was not statistically significant between the intervention group and the control group. The pooled mean difference of length of ICU stay was 0.44 h (95%CI: -0.58-1.45). The pooled mean difference of postoperative hospitalization was -1.77 d in the intervention group vs the control group [95%CI: -2.41-(-1.12)]. CONCLUSION Preoperative inspiratory muscle training may decrease the duration of postoperative hospitalization for patients undergoing cardiac surgery. More high-quality studies are needed to confirm our conclusion.