Inspiratory Muscle Training Based on Anaerobic Threshold on the Functional Capacity of Patients After Coronary Artery Bypass Grafting: Clinical Trial

Cardiac rehabilitation after cardiac surgery: An important underutilized treatment strategy

Physical inactivity remains in high levels after cardiac surgery, reaching up to 50%. Patients present a significant loss of functional capacity, with prominent muscle weakness after cardiac surgery due to anesthesia, surgical incision, duration of cardiopulmonary bypass, and mechanical ventilation that affects their quality of life. These complications, along with pulmonary complications after surgery, lead to extended intensive care unit (ICU) and hospital length of stay and significant mortality rates. Despite the well-known beneficial effects of cardiac rehabilitation, this treatment strategy still remains broadly underutilized in patients after cardiac surgery. Prehabilitation and ICU early mobilization have been both showed to be valid methods to improve exercise tolerance and muscle strength. Early mobilization should be adjusted to each patient's functional capacity with progressive exercise training, from passive mobilization to more active range of motion and resistance exercises. Cardiopulmonary exercise testing remains the gold standard for exercise capacity assessment and optimal prescription of aerobic exercise intensity. During the last decade, recent advances in healthcare technology have changed cardiac rehabilitation perspectives, leading to the future of cardiac rehabilitation. By incorporating artificial intelligence, simulation, telemedicine and virtual cardiac rehabilitation, cardiac surgery patients may improve adherence and compliance, targeting to reduced hospital readmissions and decreased healthcare costs.

Inspiratory Muscle Training in Patients in the Postoperative Phase of Cardiac Surgery: A Systematic Review and Meta-Analysis

To review the evidence about inspiratory muscle training (IMT) in patients in postoperative of cardiac surgery. We conducted this systematic review used the databases Ovid, LILACS, CINAHL, PubMed, PEDro, and CENTRAL. Randomized clinical trials that addressed IMT after cardiac surgery were selected. The outcomes assessed were maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), tidal volume (TV), peak expiratory flow (PEF), functional capacity (6-minute walk test) and length of hospital stay. The mean difference between groups and the respective 95% confidence interval (CI) were calculated and used to quantify the effect of continuous outcomes. Seven studies were selected. The IMT was superior to the control over MIP 15.77 cmH2O (95% CI, 5.95-25.49), MEP 15.87 cmH2O (95% CI, 1.16-30.58), PEF 40.98 L/min (95% CI, 4.64-77.32), TV 184.75 mL (95% CI, 19.72-349.77), hospital stay -1.25 days (95% CI, -1.77 to -0.72), but without impact on functional capacity 29.93 m (95% CI, -27.59 to 87.45). Based on the results presented, IMT was beneficial as a form of treatment for patients after cardiac surgery.

Inspiratory muscle training and functional capacity following coronary artery bypass grafting in high-risk patients: A pilot randomized and controlled trial

Background

Coronary artery bypass graft (CABG) surgery is associated with worsened functional capacity, pulmonary complications, and increased length of hospital stay. These negative effects are exacerbated in patients who are at high risk of post-operative (PO) pulmonary complications before CABG. Inspiratory muscle training (IMT) has been shown to benefit CABG patients in their recovery process. However, in high-risk patients, there is little evidence to support the post-operative implementation of IMT for purposes of faster recovery.

Aim

The aim of the study was to test the hypothesis that IMT improves the functional capacity, pulmonary complications, and length of hospital stay in patients prone to pulmonary complications who had undergone CABG.

Methods

This is a pilot clinical trial carried out with patients at high risk for pulmonary complications in the PO phase. In the pre-operative period, maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and 6-min walk test (6MWT) were determined and administered. On the first PO day, patients were divided into two groups: A control group (CG) that received routine intervention and an IMT group that, in addition to routine care, was subjected to an IMT protocol until hospital discharge. On the day of discharge, the patients were reassessed with respect to ventilatory muscle strength, functional capacity, PO complications, and length of stay.

Results

Twenty-nine patients were evaluated, 15 in the CG and 14 in the IMT group. No significant differences were observed in relation to MIP (difference between the mean of -7 cmH₂O; 95% CI = -16.52-2.52), MEP (difference between the mean of -7cm H₂O; 95% CI = -15.39-1.39), and in the 6MWT (difference between the mean of -9 m; 95% CI = -43.71-25.71). There was a decrease in the length of stay in the IMT group compared to the CG (9 ± 3 vs. 12 ± 4 days; P = 0.04). The IMT group had a lower rate of atelectasis and pneumonia.

Conclusion

IMT does not minimize the loss of functional capacity, but it reduces pulmonary complications and the length of stay of patients undergoing CABG who are preoperatively at a high risk of pulmonary complications.

Relevance for Patients

The increase in ventilatory muscle strength, associated with IMT, can reduce PO pulmonary complications, resulting in shorter hospital stays, and improved quality of life.