PL-LBA-2153

J.F. Cursino de Moura¹, C. Bitencourt Soares de Oliveira¹, A.P. Freire², M. Russell Elkins³, F. Lopes Pacagnelli⁴

¹Universidade do Oeste Paulista, Medicina, Presidente Prudente, Brazil, ²Central Washington University, Health Sciences, Ellensburg, United States, ³University of Sydney, Faculty of Medicine and Health, Sydney, Australia, ⁴Universidade do Oeste Paulista, Fisioterapia, Presidente Prudente, Brazil

Background: Postoperative pulmonary complications (PPCs) are particularly problematic after cardiac surgery; for example, hospital-acquired pneumonia can increase hospital costs by up to US$ 30,000 per patient. Respiratory muscle training (RMT) is one of the strategies to improve the strength of the respiratory muscles in patients undergoing cardiac surgery. The effects of preoperative RMT on PPCs and other clinical outcomes following cardiac surgery remain unclear. Some systematic reviews have investigated the effects of RMT on clinical outcomes after cardiac surgery, but each with important limitations. Furthermore, a few years ago, insufficient evidence on this topic prompted a call from experts for further research into RMT before cardiac surgery, and subsequent trials have been published. Therefore, it is appropriate to conduct a current review to help clinicians make better decisions about the likely benefit of RMT in this population, based on all the available evidence.

Purpose: To determinethe effect of preoperative RMT on the incidence of PPCs in patients undergoing open cardiac surgery. Additionally, to estimate the effect of RMT on the duration of mechanical ventilation, oxygenation, postoperative length of stay and respiratory muscle strength in these patients.

Methods: We performed a systematic review of randomised trials with meta-analysis. The participants were adults undergoing elective open cardiac surgery. The intervention investigated was preoperative RMT, where the comparison group received sham training or no intervention. The primary outcomes were PPCs, length of hospital stay, respiratory muscle strength, oxygenation and duration of mechanical ventilation. The methodological quality of studies was assessed using the PEDro scale and the overall certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

Results: Eight trials involving 697 participants were included. The median PEDro score of the trials was 6 (range 4 to 8). Compared with the control group, the RMT group had fewer PPCs (RR 0.51, 95% CI 0.38 to 0.70), less pneumonia (RR 0.44, 95% CI 0.25 to 0.78) and shorter hospital stay (MD −1.7 days, CI −2.4 to −1.1). The RMT group had higher maximum inspiratory pressure values at the end of the training protocol (MD 12 cmH₂O, 95% CI 8 to 16) and between the fourth and seventh postoperative day (MD 14 cmH₂O, 95% CI 7 to 22). The mechanical ventilation time was similar in both groups (MD −0.2 hr, 95% CI −2.0 to 1.5). The effect on oxygenation was unclear. The quality of evidence was high for pneumonia, length of hospital stay, maximum inspiratory pressure and mechanical ventilation time.There were no adverse events related to the respiratory training.

Conclusions: Preoperative RMT reduced the risk of PPCs generally and pneumonia specifically after cardiac surgery. The training also improved the maximal inspiratory pressure and reduced length of hospital stay.

Implications: Respiratory muscle training is low cost, low risk and easy for patients to self-administer at home in preparation for their surgery. The effects on PPCs alone were large enough to warrant use of RMT in this population. In addition, RMT reduces length of hospital stay by a worthwhile amount.

Funding acknowledgements: This study was not funded.

Keywords:
Respiratory muscle training
Postoperative pulmonary complications
Systematic review

Topics:
Cardiorespiratory

Did this work require ethics approval? No

Reason: Not required. Systematic review, no human subjects or animals included in the study.