effect of lidocaine and magnesium sulfate on prevention of ventricular fibrillation in coronary artery bypass grafting surgery

One of the most common events, after the release of aortic cross-clamp in patients undergoing coronary artery bypass grafting surgery is reperfusion induced ventricular fibrillation, which occurs in 74% of 96% of patients. Regarding the controversies over the use of lidocaine or magnesium sulfate for the prevention of ventricular fibrillation following the release of aortic cross-clamp, this study was designed to compare the effectiveness of magnesium sulfate and lidocaine to suppress ventricular fibrillation. In a double blind, prospective, randomized, controlled trial study, 76 patients who were candidates for elective coronary artery bypass grafting surgery were divided into three groups including Group A [lidocaine, n=26], group B [magnesium sulfate, n=25], and group C [normal saline, n=26]. Lidocaine [1.5 mg/Kg], magnesium sulfate [30 mg/Kg] and normal saline were administered 5 minutes before the release of aortic cross clamp. The incidence of ventricular fibrillation significantly decreased in patients receiving magnesium sulfate [12% vs. 26.9% and 44% in patients who received lidocaine and normal saline, respectively] There was no statistically significant difference between the groups with respect to age, ejection fraction [L/ min], anesthetic time [min], cross-clamping time [min], PH, HCT [%], and serum K+ level [meq]. The administration of lidocaine and magnesium sulfate before the release of aortic cross-clamp reduces the incidence of postoperative ventricular fibrillation in adult patients undergoing coronary artery bypass grafting surgery with cardiopulmonary bypass. In our study, magnesium sulfate was more efficient in prevention of ventricular fibrillation than lidocaine. Administration of magnesium sulfate [30 mg/kg] caused no toxic effect and wais safe for patients undergoing coronary artery bypass grafting surgery with cardiopulmonary bypass

Impact of bispectral index monitoring versus clinical judgment as a guide for conduction of anesthesia on serum cortisol level in coronary artery bypass graft surgery

Inadequate depth of anesthesia leads to release of stress hormones. Electroencephalographic monitoring by bispectral index is a guide to asses the depth of anesthesia. The aim of the present study was to measure the serum cortisol levels as an index of stress response in patients who are candidates for coronary artery bypass graft surgery in two groups of patients. Seventy-six patients who were scheduled for primary elective cardiopulmonary bypass were enrolled in a double- blind randomized study. The patients were divided into two groups. The infusion of anesthetic drugs was guided by bispectral index in group I [n=38], and by clinical judgment in group II [n=38]. For all the patients the blood cortisol level was measured four times during operation. Serum cortisol levels decreased during operation in both groups, reaching 67.8% of the baseline in group I and 63.2% of the baseline in group II. There were no significant differences in mean serum cortisol levels between the two groups [p<0.09]. Preoperatively, the mean blood cortisol level was 19.94 micro g/dl in group I and 16.89 micro g/dl in group II which reached to 10.48 micro g/dl in group I and 6.42 micro g/dl in group II postoperatively. There was no significant difference between two groups regarding bispectral index values. It seems that monitoring of the patients by clinical judgment or bispectral index has equal influences on serum cortisol levels during coronary artery bypass graft surgery