ABSTRACT
BACKGROUND: Esmolol has been applied to lower myocardial oxygen consumption and creates a quieter operative field by reducing systemic blood pressure and heart rate but can cause a certain amount of hemodynamic instability during minimally invasive direct vision coronary artery bypass graft (MIDCAB). The aim of this study was to compare the hemodynamic differences between two methods; inducing hypotension and bradycardia between esmolol infusion alone, and concomitant use of neostigmine during MIDCAB anesthesia. METHODS: Twenty MIDCAB patients were randomly allocated into two groups, group E (n = 10) receiving esmolol 0.3 mg/kg/min, group EN (n = 10) receiving esmolol 0.2 mg/kg/min and neostigmine 1.0 mg for induced hypotension and bradycardia during coronary anastomosis. The hemodynamic parameters were evaluated 10 minutes after induction of anesthesia (T1), 10 minutes after beginning of operation (T2), 5 minutes before the end of anastomosis (T3) and 10 minutes after the end of anastomosis (T4). Data were analyzed by ANOVA test for intragroup comparisons, and by T-test for intergroup comparisons with significance set at a P value of < 0.05. RESULTS: Heart rate significantly decreased at T3 in both groups and more in group EN. Systolic blood pressure decreased at T3 in both groups and there were no group differences but more episodes of extreme hypotension in group E. The cardiac index significantly decreased at T3 in both groups and more in group E. There was a small but significant increase in pulmonary capillary wedge pressure at T3 and T4 in group E and no change of central venous pressure in both groups. CONCLUSION: Concomitant use of neostigmine during esmolol infusion produces more reliable induced hypotension and bradycardia than esmolol infusion alone for MIDCAB anesthesia in terms of prevention of myocardial ischemia and easiness of anastomosis technique.