Effect of preoperative respiratory rehabilitation on post operative outcomes in coronary artery bypass graft patients: a randomized clinical trail

Background: Coronary artery bypass graft, a surgical way to bypass blocked portions of coronary arteries, comes with many postoperative complications including a decline in pulmonary function. Some preoperative exercises help reduce such pulmonary complications and improve postoperative pulmonary function. Objectives: to determine the effects of preoperative respiratory rehabilitation on post-operative pulmonary functioning in CABG patients. Methods: a randomized clinical trial with two groups was conducted in the Armed Forces Institute of Cardiology & NIHD Rawalpindi from June 2022- July 2023. The n=86 participants included ages between 40-65 years, those undergoing elective CABG surgery for any cardiac disease, patients who covered at least 400 steps on a 6-minute walk test, patients with ejection fraction 45% or more, and those who reserved at 4th postoperative day of CABG. Group A received Pre and Postoperative Respiratory Rehabilitation. Both groups received postoperative care for 4 days. All the patients were assessed for FEV1, FVC, and their ratio (FEV1/FVC) at baseline, on the 7th day, and on the 4th postoperative day of CABG surgery Results: the experimental group significantly improved FVC compared to the control group, with moderate improvements observed (p=0.03*) by Day 7 and substantial improvements (p<0.001) by Post Day 4. When compared, at day 7 before surgery no significant difference (p=0.07) observed but The experimental group showed more significant improvement (p=0.006**) post operative day 4. Overall, no significant difference (p<0.05) between the experimental group and the control group consistently in all assessment level of FEV₁/FVC ratio. Conclusion: The experimental intervention demonstrated positive effects on FVC and FEV1, reflecting improved lung function, while no significant impact was observed on the FEV1/FVC ratio, suggesting that the intervention did not affect the airflow dynamics in relation to lung volume. Keywords: Forced expiratory volume, Forced vital capacity, FEV1/FVC ratio, preoperative respiratory rehabilitation, coronary artery bypass graft surgery