[ effect of low-dose ketamine infusion on hemodynamic change in coronary artery bypass graft surgery]

Cardiopulmonary bypass often causes a stress hormonal response with subsequent changes in hemodynamic and organ perfusion. Human studies involving cardiopulmonary bypass have shown that very low doses of ketamine can attenuate inflammatory and stress markers, without adverse effects. The aim of this study was to investigate whether low dose infusion of ketamine have hemodynamic stability effect in coronary artery bypass surgery. In this double blind-controlled trial, 50 patients undergoing on-pump CABG were randomly assigned to receive either 1.25mcg/kg/min of ketamine infusion [Ketamine group, n=25] or normal saline infusion [Control group, n=25] during 48 hours after induction of anesthesia. hemodynamic measurement including blood pressure, heart rate, central venous pressure, cardiac output, cardiac index, systemic venous resistance, arterial blood gas and lactate were measured previous to induction [T1], 4 h, 24h, and48h after the surgery [T2,T3 and T4]. The data were evaluated with using of variance analyzing test and repeated measurement. There were significant interaction effect between time [pre operation, 4, 24 and 48 hours after operation] and group of study [ketamine and placebo] in assessment of systolic blood pressure [p=0.0001], diastolic blood pressure[p=0.0001], heart rate [p=0.004], central venous pressure [p=0.0001] and lactate [p=0.035]. These indicate that ketamine caused decrement in tissue perfusion. Those interactions were not statistically significant for other parameters [p>0.05]. low dose ketamine during and 48 hours after operation not only didn't show hemodynamic stability effect but also decreased tissue perfusion slightly

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