Investigation of respiratory muscle strength in patients with chronic obstructive pulmonary disease undergoing coronary artery bypass grafting surgery

Aim of this study: In this prospective, clinical study; investigation of the changes in respiratory functions and respiratory muscle strength (RMS) was aimed in patients with chronic obstructive pulmonary disease (COPD) undergoing coronary artery bypass grafting (CABG) surgery.Material and Methods: After Ethics Committee approval, 60 patients undergoing CABG surgery were assigned into two groups; (i) Control group (n:30) and (ii) COPD (n:30) group. Preoperative and postoperative FEV1, FVC, Pimax, SNIP, PEmax values were obtained. Fisher exact, x2, Mann-Whitney U and Wilcoxon Signed Rank tests were used for statistical analysis, p < 0.05 was considered significant.Results: The demographics did not differ between the groups. Except preoperative FEV1 value (p=0,00), no significant difference was found preoperatively between the groups. The values of FEV1 (p=0.00, p=0.00, respectively), FVC (p=0.00, p=0.00, respectively), Pimax (p=0.00, p=0.00, respectively), SNIP (p=0.00, p=0.00, respectively) and PEmax (p=0.00, p=0.00, respectively) decreased significantly at the postoperative period both in the control and COPD groups. No significant difference was found in regard to pulmonary function tests (PFT) and RMS between the groups postoperatively (p ? 0.05). In the control group, the decreases in the percentage of FEV1 (p=0.01) and FVC values (p=0.02) were significantly higher than those of COPD group. Additionally, no significant difference was found in the percent age decrease of the RMS values between the groups (p ? 0.05).Conclusion: While low preoperative FEV1 was obtained in patients with COPD, the values of FVC and RMS were similar in patients with and without COPD. Independent of the presence of COPD, the surgical procedure decreased the values of PFT and RMS in patients of both groups. The values of FEV1 and FVC decreased more in patients without coexisting pulmonary disease when compared to COPD patients. However, the presence of COPD did not affect the RMS values and the changes in these values caused by surgery.Keywords: Cardiopulmonary bypass, chronic obstructive pulmonary disease, pulmonary function test, respiratory muscle strength test.