Inspiratory muscle training improves tidal volume and vital capacity after CABG surgery

Rev Bras Cir Cardiovasc. 2012 Jul-Sep;27(3):362-9. doi: 10.5935/1678-9741.20120063.
[Article in English, Portuguese]


Objective: To evaluate lung function and respiratory muscle strength in the postoperative period and investigate the effect of inspiratory muscle training on measures of respiratory muscle performance in patients undergoing coronary artery bypass grafting.

Methods: A randomized study with 47 patients undergoing coronary artery bypass grafting with cardiopulmonary bypass. They were divided into study group (SG) 23 patients and control group (CG) 24 patients, mean age 61.83 ± 8.61 and 66.33 ± 10.20 years, EuroSCORE SG 0.71 ± 0.0018 and CG 0.76 ± 0.0029, respectively. The study group underwent physical therapy and inspiratory muscle training with threshold IMT® and CG underwent conventional physiotherapy. We compared the maximal respiratory pressures (MIP and MEP), tidal volume (TV), vital capacity (VC) and peak expiratory flow (peak flow) preoperatively (Pre-OP), 1st (PO1) and 3rd (PO3) postoperative day.

Results: There was a significant reduction in all variables measured on PO1 compared to preoperative values in both groups, MIP (P <0.0001), MEP (P <0.0001), TV SG (P <0.0004) and CG (P <0.0001) and VC SG (P <0.0001) and CG (P <0.0001) and peak flow (P <0.0001). At PO3, SG presented higher value of VC, GE 1230.4 ± 477.86 ml vs. GC 919.17 ± 394.47 ml (P=0.0222) and TV SG 608.09 ± 178.24 ml vs. CG 506.96 ± 168.31 ml (P= 0.0490).

Conclusion: Patients undergoing cardiac surgery experience reduced ventilatory capacity and respiratory muscle strength after surgery. Muscle training was performed to retrieve TV and VC in the PO3, in the trained group.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Analysis of Variance
  • Breathing Exercises*
  • Coronary Artery Bypass / rehabilitation*
  • Female
  • Humans
  • Length of Stay
  • Male
  • Middle Aged
  • Muscle Strength
  • Peak Expiratory Flow Rate / physiology
  • Postoperative Period
  • Respiratory Muscles / physiology*
  • Statistics, Nonparametric
  • Tidal Volume / physiology
  • Time Factors
  • Treatment Outcome
  • Vital Capacity / physiology*