Abstract: 【Abstract】〓Objective〓To observe the effects of dexmedetomidine preconditioning on myocardial enzyme and cardiac troponin I in patients with heart value replacement and explore the protective effects on myocardium with ischemia/reperfusion injury. Methods〓Fifty patients undergoing heart valve replacement were randimized into dexemedetomine group (group D, n=25) and control group (group C, n=25). In group D, dexmedetomine was administered intravenously at 0.5 μg·kg-1·h-1 through a bolus infusion in 15 min before anesthesia and then continuous infusion- pumped carried on until aortic clamping, while the same volume of normal saline were given in group C. The central venous blood samples were collected in both groups at pre-opreration (T0), 30 min after aortic clamp (T1), 1 h after aortic-off clamping (T2), end of surgery (T3), 24 h after operation (T4) for detecting the plasma creatine kinase (CK), creating kinase-MB (CK-MB) activity and cardiac treponin I (cTnI) concentration. Meanwhile the rate of heart spontaneous rebeating, arrhythmia, left ventricular ejecfion fraction (LVEF) and usage of cardiac inotropic agents were recorded. Rusults〓The plasma CK, CK-Mb activity and the cTnI concentration, the doses of dopamine and adrenalin in group D were significantly lower than that in group C. There were no significantly statistical differences in the rate of heart spontaneous rebeating, arrhythmia between two groups. The postoperative LVEF was significantly higher in group D than in group C. Conclusion〓Dexmedetomidine pretreatment can attenuate the myocardial injury in patients undergoing cardiac valve replacement.

Key words: Dexmedetomidine, Myocardial protection, Reperfusion injury, Cardiac troponin I, Creatine kinase

摘要：

【摘要】〓目的〓观察右美托咪定预处理对脏瓣膜置换术患者心肌肌钙蛋白Ⅰ和心肌酶学的影响,探讨其对缺血再灌注损伤心肌的保护作用。方法〓拟择期行瓣膜置换术患者50例随机分为右美托咪定组(D组,n=25)和对照组(C组,n=25)。D组在麻醉诱导前经15 min静脉泵注右美托咪定0.5 μg/kg,随后以0.5 μg·kg^-1·h^-1速率泵注至阻断主动脉。C组泵注等容量生理盐水。所有患者手术前(T₀),主动脉阻断30 min(T₁)、主动脉开放1 h(T₂),术毕(T₃)和术后24小时(T₄)抽血测定磷酸肌酸激酶(CK)、磷酸肌酸激酶同工酶(CK-MB)的活性及心肌肌钙蛋白I(cTnI)的浓度。观察自动复跳率、心律失常发生率、左室射血分数(LVEF)以及血管活性药物使用情况。结果〓与C组相比,D组的cTnI浓度、CK和CK-MB的活性、多巴胺和肾上腺素用量低于C组;两组自动复跳率和心律失常发生率无统计学差异;D组术后LVEF值高于C组。结论〓右美托咪定预处理可减轻瓣膜置换患者的心肌损伤。

关键词: 右美托咪定, 心肌保护, 再灌注损伤, 心肌肌钙蛋白I, 肌酸激酶