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

ABSTRACT

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