Effect Of Different Doses Of Dexmedetomidine On Myocardial Injuryin Patients With Rheumatic Heart Valve Replacement Surgery

Objective To investigated effect of different doses of dexmedetomidine on perioperative myocardial injury in patients with rheumatic heart valve replacement surgery.Methods 60 patients, sex not limited, 50~70 years, ASA grade II or III, NYHA class II or III,were given rheumatic heart valve replacement surgery. The patients had no serious liver and kidney failure, no drug allergy history, no history of mental illness, no severe atrioventricular block(block is smaller than the second degree). Patients selected in randomized, double-blind were divided into three groups(n = 20): control group(group C),given dexmedetomidine 0.3 μg·kg-1 group(DEX1group), dexmedetomidine given 0.6 μ g·kg-1 group(DEX2 group). DEX1 group and DEX2 group at 10 min after tracheal intubation were respectively administrated with dexmedetomidine 0.3 μ g·kg-1 or 0.6 μ g·kg-1 in the infusion time of 10 min, followed respectively infusion of 0.3 μ g·kg-1·h-1 or 0.6 μ g·kg-1·h-1 dexmedetomidine to closed chest. Group C given the same volume of saline. Central venous blood were drawn respectively before anesthesia induction(T0), 2h after CPB(T1), 24 h after CPB(T2), 48 h after CPB(T3), 72 h after CPB(T4). Plasma muscle calcium protein I(Cardiactrofonin I, c Tn I) 、creatine kinase(Creatine Kinase MB, CK-MB) 、Malondialdehyde(MDA) 、Superoxide Dismutase( SOD) 、Tumor Necrosis Factor-α(TNF-α) and Interleukin-6(IL-6) were measured by radioimmunoassay quantitative and mean arterial pressure and heart rate were recorded at each time point. Extubation time, ICU stay, postoperative inotropic score 24 h after operation, drainage 24 h after operation, cardia auto-resuscitation rates and adverse cardiovascular events were recorded.Results 3 groups of patients with general situation, MAP each time, time of extubation, ICU stay time and drainage volume 24 h after operation showed no significant difference(P > 0.05). c Tn I、CK-MB、IL-6、TNF-α、MDA、SOD and HR had no significant difference in the T0 time points(P > 0.05). Compared with group C, IL-6、TNF-α and CK-MB value reduced in the T1 time points in group DEX1(P<0.05);HR reduced in the T1 time points in group DEX1 and DEX2(P<0.05). Compared with group C,CK-MB and MDA value reduced and SOD value increased in the T1-2 time point in group DEX2(P < 0.05); IL-6 and TNF-α reduced in the T1~3 time point in group DEX2(P<0.05); c Tn I reduced in the T2-4time point in group DEX2(P<0.05). Compared with group DEX1, IL-6 decreased in the T1-2 time point in group DEX2(P<0.05)and TNF-α reduced in the T1 time point in group DEX2(P<0.05). Compared with group C, inotropic score 24 h after operation and cardiovascular adverse events significantly reduced in group DEX1 and group DEX2(P < 0.05). Compared with group C, the heart of auto-resuscitation rate markedly increased(P<0.05).Conclusion: Dexmedetomidine effectively inhibited the increase in plasma CK-MB、c Tn I 、IL-6、TNF-α and MDA, while effectively inhibited the decrease in plasma SOD after cardiopulmonary bypass, and cardia auto-resuscitation rate was significantly increased, 24 h postoperative inotropic score and the incidence of cardiovascular events was significantly lower. So dexmedetomidine has a protective effect on perioperative myocardial injury on cardiopulmonary bypass(CPB) in patients with rheumatic heart valve replacement surgery under this clinical conditions.