Effect Of Esmolol On Myocardial Protection And Hemodynamics Changes In Patients Undergoing Cardiac Surgery Via Cardiopulmonary Bypass

Objective:the aims of the study are to investigate the protective effect of esmolol on myocardial ischemia/reperfusion injury and the influence on the hemodynamic changes in patients undergoing cardiac surgery via cardiopulmonary bypass(CPB), in order to provide evidence for rational administration of medicine in clinical practice.Methods:24 patients, aged 40 to 80 years old with cardiac function 2-3 degree according to New York Heart Association (NYHA) and undergoing cardiac surgery via CPB, were randomly assigned to two groups, esmolol group (group 1,n=12) and control group (group 2,n=12). The patients with coronary artery disease had no history of acute myocardial infarction (AMI) and the patients with cardiac valve disease were no rheumatoid activity four weeks before surgery. All patients fulfilled following criteria:preoperative 24 hours cardiac makers within the normal range and the ejection fraction>40%(EF>40%), and no severe intracardiac shunt, no severe disorders of lung, liver, kidney, skeletal muscle and immune system. No history of oral administration of hypoglycemic agents and theophylline recently. At the beginning of chest incision,esmolol (70ug/kg/min) were given in patients of group 1 and normal saline in group 2,and adjusting dosage every 2 minutes with lOug/kg/min each time to maintain the heart rate within 80% of baseline level until the start of CPB. Cardiac markers were monitored before aortic intubation (T1),30 minutes after aortic cross-clamping (T2), aortic opening immediately (T3) and 120 minutes (T4). During and after operation, mean blood pressure, central venous pressure,heart rate,resuscitation,arrhythmia and postoperative complications were also observed,Results:Hemodynamic markers during operation:only the central venous pressure after intubation was significantly higher in the esmolol group compared to the control group (P<0.05), no significant differences were observed for the other hemodynamic parameters between the groups. Postoperative conditions:the mean arterial blood pressure was significantly lower in the treated group than that in the control group after five and ten hours admitted to the ICU (P<0.05). Cardiac markers:TnI release were lower in esmolol group than the control group for four time points, and there were significant differences both in the T1 time point (P<0.001) and T4 time point (P< 0.05).Conclusions:Esmolol administration lowers release of cardiac markers under CPB but does not affect hemodynamics. Therefore it has a cardio-protective effect.