The effects of N-acetylcysteine on pulmonary functions in patients undergoing on-pump coronary artery surgery: a double blind placebo controlled study.

Objective: To investigate the effects of N-acetylcysteine (NAC) on pulmonary function tests and arterial blood gases in patients undergoing on-pump coronary artery surgery.

Patients And Methods: The effect of NAC was assessed within the scope of a prospective, single center, double-blind, placebo-controlled, parallel group study. Eighty-two patients undergoing coronary artery bypass grafting were randomized into two groups to receive either placebo (group 1, n = 40) or NAC (group 2, n=42). Both the NAC group and the placebo-receiving control group also included a COPD subgroup consisting of patients with an FEV1/FVC ratio of < 0.7 and an FEV1 value of 50-80%. Pulmonary function tests were performed preoperatively and on postoperative day 60.

Results: Both groups were similar with respect to age, gender, preoperative risk factors, ejection fraction (EF), mean cross-clamp time, ventilation time, intensive care unit (ICU) stay, atrial fibrillation (AF) and hospital stay (p > 0.05). Postoperative FVC and FEV1 values in group 1 and the postoperative FEV1, FEV1/FVC and FEF 25-75 values in group 2 were lower in comparison to their preoperative values. However, in both group 1 and 2, the decreases observed in these parameters were not statistically significant (p > 0.05). In the COPD subgroup of group 1, a postoperative decrease was observed in the FEV1 and FEF25-75 values, with the FEV1 decreasing by 4.55%, and the FEF25-75 decreasing by 4.2% (p < 0.05). In the COPD subgroup of group 2, no significant decrease was observed in the pulmonary function test values (p > 0.05).

Conclusions: This study demonstrated that NAC administration in COPD patients undergoing on-pump coronary artery surgery resulted in the preservation of pulmonary functions.