右美托咪啶对体外循环下心脏瓣膜置换术患者心肌缺血再灌注损伤的影响

目的：评价右美托咪啶对体外循环（CPB）下心脏瓣膜置换术患者心肌缺血再灌注损伤的影响。方法：择期CPB下心脏瓣膜置换术患者40例，性别不限，年龄40～65岁，ASA分级Ⅱ或Ⅲ级，采用随机数字表法，将患者随机分为两组（n=20）：对照组（C组）和右美托咪啶组（D组）。麻醉诱导前D组静脉注射右美托咪啶0.6μg /kg（15min内），随后以0.2μg？kg-1？h-1速率输注至术毕，C组给予等容量生理盐水。分别于麻醉诱导前（T0）、主动脉开放后30min（T1）、6h（T2）、12h（T3）、24h（T4）、48h（T5）时采集静脉血样，测定血浆心肌肌钙蛋白I（cTnI）和肌酸激酶同工酶（CK-MB）的浓度，以及血清TNF-？和IL-6的浓度。记录手术时间、主动脉阻断时间、主动脉开放后自动复跳率、CPB时间、术后气管拔管时间、ICU停留时间。结果：与T0时比较，T1～4时C、D两组血浆cTnI和CK-MB浓度及血清TNF-？和IL-6浓度升高（P〈0.05）；与C组比较，T1～4时D组血浆cTnI和CK-MB浓度及血清TNF-？和IL-6浓度降低（P〈0.05）；与C组比较，D组术后气管拔管时间和ICU停留时间缩短（P〈0.05）。结论：右美托咪啶能减轻体外循环下心脏瓣膜置换术患者心肌缺血再灌注损伤，其机制可能与抑制促炎性细胞因子释放有关。

Effects of dexmedetomidine on myocardial ischemia-reperfusion injury in patients undergoing cardiac valve replacement under cardiopulmonary bypass

AIM： To investigate the effect of dexmedetomidine on myocardial ischemia-reperfusion injury in patients undergoing cardiac valve replacement under cardiopulmonary bypass（CPB）. METHODS： Forty ASA Ⅱ or Ⅲ patients of both sexes, aged 40-65 yr, scheduled for elective cardiac valve replacement under CPB, were randomly divided into 2 groups（n=20 each）： contral group（group C） and dexmedetomidine group（group D）. Dexmedetomidine 0.6μg /kg was injected intravenously over 15 min before induction of anesthesia, followed by infusion at 0.2μg·kg-1·h-1 until the end of operation in group D. While the equal volume of normal saline was given in group C. Blood samples were obtained from the vein before induction of anesthesia（T0） and at 30min, 6, 12, 24 and 48 h after aortic uncalmping（T1-5） for determination of plasma concentrations of cardiac troponin-I（cTnl） and creatine kinase isoenzyme-MB（CK-MB） and serum concentrations of TNF-· and IL-6. The duration of CPB, time of operation, time of aortic calmping, extubation time, duration of stay in ICU, and the rate of restoration of spontaneous heart beat were recorded. RESULTS： Compared with T0, the plasma concentrations of cTnI and CK-MB and the serum concentrations of TNF-· and IL-6 were significantly increased at T1～4 in group C and D（P〈0.05）. Compared with group C, the plasma concentrations of cTnI and CK-MB and the serum concentrations of TNF-· and IL-6 were significantly decreased at T1～4 in group D, while the extubation time and duration of stay in ICU were decreased in group D（P〈0.05）. CONCLUSION： Dexmedetomidine can reduce the myocardial ischemia-reperfusion injury in patients undergoing cardiac valve replacement under CPB, and the mechanism may be related to inhibition of the release of proinflammatory cytokines.