Efeitos do treinamento muscular respiratório pré-operatório nas complicações pulmonares após cirurgia cardíaca: uma revisão sistemática com meta-análise

Abstract

Introduction: Pulmonary dysfunction in the postoperative period of cardiac surgery is a frequent event that can lead to serious complications and increased mortality. The respiratory muscle training (RMT) prior to cardiac surgery aims to improve preoperative conditioning and postoperative outcomes. Objective: To assess the effects of preoperative RMT on respiratory complications after elective cardiac surgery. Methods: Searches were performed on eleven electronic databases in July 2021. Randomised clinical trials recruiting patients over 18 years old undergoing elective open cardiac surgery were included. The intervention was preoperative RMT and the comparison group was no treatment or sham RMT. The primary outcomes were respiratory complications, length of hospital stay, oxygenation variables, respiratory muscle strength and duration of mechanical ventilation. The methodological quality of studies was assessed using the PEDro scale and the overall quality of the evidence using the GRADE approach (Grading of Recommendations, Assessment, Development and Evaluation). Results: Eight studies reporting data for 697 participants were included. Compared to the control group, the respiratory training group had fewer pulmonary complications (n = 645, RR 0.51, 95% CI 0.38 to 0.70), less pneumonia (n = 645, RR 0.44, 95% CI 0.25 to 0.78), shorter hospital stay (n=531, MD -1.72 days CI -2.4 to -1.0) and higher maximum inspiratory pressure values at the end of the training protocol (n = 666, MD 12 cmH2O, 95% CI 7 to 18). Mechanical ventilation time was not different between groups (n=505, MD -0.24 hour, 95% CI -2 to 1,5 hours). The quality of evidence was high regarding pneumonia, length of hospital stay, maximum inspiratory pressure and mechanical ventilation time. Conclusion: RMT reduced the risk of respiratory complications generally and pneumonia specifically in the postoperative period after cardiac surgery. There was also a clear benefit of RMT regarding MIP and length of hospital stay. The effects on respiratory complications were large enough to warrant use of RMT in this population, although additional studies investigating mortality and the optimal training protocol are needed.