Respiratory muscle training in patients submitted to coronary arterial bypass graft

1) To demonstrate the impaired ventilatory capacity during the post operatory period, in patients submitted to coronary arterial bypass graft surgery (CABG). 2) To test the hypothesis that the respiratory muscle training (RMT), performed after the surgery, may increase the ventilatory capacity in this population.

Thirty-eight patients (age: 65 ± 7 years, 29 male), whose underwent CABG with extra-corporeal circulation. Patients were randomized in two groups: 23 patients in the RMT group and 15 in the control group (CO). RMT group received conventional physiotherapy plus RMT. The CO group received the conventional physiotherapy. Evaluated parameters: maximum inspiratory and expiratory pressures (MIP) (MEP), dyspnea (Borg), peak expiratory flow (PEF), pain, tidal volume and hospitalization days. Measures were performed at pre, first post operatory day and also at the patients discharge from the hospital).

MIP and MEP in the RMT group were higher when compared with CO at the patients discharge (MIP: 90 ± 26 vs. 55 ± 38 cmH2O, P = 0.01) (MEP: 99 ± 30 vs. 53 ± 26 cmH2O, P = 0.02). The PEF was higher after hospitalization in the RMT group (237 ± 93 vs. 157 ± 102 lpm, P=0.02). Tidal volume was also higher in the RMT group at discharge (0.71 ± 0.21 vs. 0.44 ± 0.12 liters, P = 0,00). No differences were observed among the groups in the aspects: admission days, dyspnea and pain.

Patients submitted to CABG presents an impaired respiratory muscle strength in their post operatory. RMT performed in this phase was effective to restore the ventilatory capacity in the following parameters: MIP, MEP, PEF and tidal volume, in this group of patients.