Role of antioxidant compounds during cardiopulmonary bypass

ABSTRACT

The aim of the present study was to determine the role of antioxidant compounds on haemodynamics during coronary artery bypass grafting using cardiopulmonary bypass. Twenty Two patients of ASA physical status III, who were scheduled to have non-urgent aortocoronary bypass grafting with a preoperative ejection fraction 0.5. Patients were randomly assigned into one of two groups [11 patients each]. Group I Patients received one gm.h[-1] of N-acetyl cysteine [Mucomyst] infusion after induction of anaesthesia and continuously till the skin closure. One gram of ascorbic acid [Vitamin C] and 400 IU of J-tocopherol [Vitamin E] were administered intravenously over 10-15 minutes at the time of rewarming. Group II Patients received placebo, equal volumes of normal saline during the same periods. Anesthetic management was the same in all patients and performed by the same surgeon. A 4- lumen, 7 F thermo-dilution pulmonary artery catheter was inserted. Hemodynamic variables Heart rate [HR], mean arterial pressure [MAP], pulmonary capillary wedge pressure [PCWP] and cardiac output [COP] were measured after induction of anaesthesia and establishment of monitoring [baseline], five minutes after coming off bypass, and at skin closure. The choice and dose of inotrops given was left to the decision of the attending anesthetist. Five minutes after coming off hypass, both MAP and COP decreased significantly in the placebo group in comparison to the treatment group. There was statistically significant decrease in MBP in the placebo group in comparison to antioxidants group, with a mean of 57.1 +/- 3.2 mmHg and 74.7 +/- 4.0 mmHg respectively. Similarly, there was statistically significant decrease in the COP in the placebo group in comparison to antioxidants group, with a mean of 3.77 +/- 0.2 and 4.33 +/- 0.3 respectively. Other variables [HR, PCWP, and SVR] did not significantly differ between both groups. At skin closure the mean HR was the only variable that showed significant change between the two groups. It was significantly higher in placebo group [82.3 +/- 9.2bpm], in comparison to antioxidant group [69.4 +/- 7.6 bpm]. The inotropic requirements were generally increased in the placebo group. Most patients in the antioxidants group [72%] required only low dose dopamine [3 micro.kg[-1.]min[-1]]. On the other hand, in the placebo group, requirements of moderate doses of dopamine [3-10 micro.kg[-1].min[-1]] and dobutamine [3-10 micro.kg[-1].min[-1]] were significantly higher. Similarly, percentage of patients who required combination of dopamine and dobutamine were high in the placebo group in comparison to treatment group. The current study proved that the combination of antioxidant compounds is beneficial to ameliorate haemodynamic changes and decrease the inotropic requirements during cardiopulmonary bypass, and would be very beneficial if used as routine therapy, especially with the high-risk surgical patients