The Influence Of Dexmedetomidine On Hemodynamics And Myocardial Protection In Patients Undergoing Cardiac Valve Replacement

Objective:This study aims to acquire new ideas and clinical basis for myocardial protection by researching the influence of dexmedetomidine on hemodynamics and myocardial protection in patients undergoing cardiac valve replacement.Methods:40patients,male or female,aged45-65years old,weighed45-75kg,ASAⅡ-Ⅲ,cardiac functionⅡ-Ⅲ,EF≥40%,undergoing elective cardiac valve (mitral valve or tricuspid valve) replacement were randomly divided into dexmedetomidine group(n=20) and compare group(n=20).All patients met the follwing conditions:no acute myocardial infarction1month before surgery,no history of heart failure and cardiac surgery,no diabetes,no allergy,no serious disorders of liver,kidney,lung.In group D, dexmedetomidine were givenlμg/kg loading dose for10min, then infusing persistently until the start of cardiopulmonary bypass(CPB)with the rate of0.4μg/kg/h.while in group C,the same of volume normal saline were given. Mean arterial pressure(MAP),heart rate(HR)were recorded at the time before operation,aftert intubation,the skin incision, stemotomy,before the start of CPB,10min after of CPB. Serum concentration of cardiac troponin I(cTnI)were measured at the time before CPB,12hour after CPB.Ejection fraction(EF) were examimed by ultrasonic cardiogram in3days after operation.Results:①Compared with before operation, values of MAP and HR in group C were significantly increased (P<0.05) at the aftert intubation,stemotomy. Compared with group C,values of MAP and HR in group D were significantly decreased (P<0.05) at the aftert intubation, steraotomy. From haemodynamics perspective,group D is more stable compared with group C (P<0.05).②Serum concentrations of cTnl were significantly decrease in group D than that in group C (P<0.05).￢alues of EF were not statistically significant in3days after operation between two groups (P>0.05)Conclusion:In elective cardiac valve surgery,1.0μg/kg loading dose dexmedetomidine followed by0.4μg/kg/h continuous infusion keep the procedure of operation stabilization by decreaseing hemodynamics fluctuation of intubation and stemotomy.Meanwhile, dexmedetomi-dine decrease release of cTnl.Therefore it has a cardio-pretective effect.