右美托咪定对体外循环下行二尖瓣置换术患者的心肌保护作用

Myocardial protective effect of dexmedetomidine on cardiopulmonary bypass in patients with mitral valve replacement

目的：观察右美托咪定（dexmedetomidine， DEX）对二尖瓣置换术患者心肌的保护作用。方法入选的48例患者随机分为两组：DEX组（ D组，25例）和生理盐水组（ C组，23例）。D组给予DEX负荷量（0．5μg／kg，10 min泵注），泵注结束后开始麻醉诱导，并以0．5μg／（kg· h） DEX维持至手术结束；C组相同的方法泵注等容量的生理盐水。两组分别在麻醉诱导前（ T0）、麻醉诱导后切皮前（T1）、体外循环开始时（T2）、体外循环结束时（T3）、停机后6 h（T4）5个时间点记录心率（HR）、平均动脉压（MAP）。在T1、T3、T4、停机后12 h（T5）、停机后24 h（T6）5个时间点采集血样测定血清肌钙蛋白I（cTnI）和缺血修饰白蛋白（IMA）。观察并记录两组患者手术时间、体外循环时间、主动脉阻闭时间、术后住院时间、心脏自动复跳率等临床指标。结果 D组在T1、T2时MAP明显高于C组（P＜0．05）。 D组在T1、T2时HR明显低于C组（P＜0．05）。 D组在T3、T4、T5、T6时cTnI水平均明显低于C组（ P＜0．05）。 D组IMA在T3、T4时明显低于C组（ P＜0畅05）。 D组自动复跳率明显高于C组（ P＜0．05）。结论 DEX能够稳定血流动力学，减轻二尖瓣置换术患者围术期心肌损伤，对心肌具有一定保护作用。

Objective To observe the protective effect of dexmedetomidine （ DEX ） on myocardium in patients with mitral valve replacement .Methods The selected patients were randomly divided into two groups：group DEX （group D, 25 cases） and saline group （group C, 23 cases）.D group was given DEX load （0.5 g/kg, l0 min injection pump）, start induction of anesthesia after pump, and 0.5 g/（ kg· h） DEX until the end of operation .Group C used saline the same way pumping capacity.Heart rate （HR）, mean arterial pressure （MAP） of the two groups were recorded at 5 time points：before induction of anesthesia （T0）, after induction of anesthesia, before skin incision （T1）, the beginning of cardiopulmonary bypass （ T2 ） , at the end of CPB （ T3 ） , 6 h after operation （ T4 ） . Blood samples were collected for determination of serum troponin I （ cTnI ） and ischemia modified albumin （IMA） in the T1, T3, T4, 12 h after operation （T5）, 24 h after operation （T6） 5 time points.Operation time, cardiopulmonary bypass time, aortic blocking time, postoperative hospitalization time, automatic rebeating rate and other clinical indicators between the two groups were also recorded . Results MAP in group D before skin incision （ T1 ） , the beginning of cardiopulmonary bypass （ T2 ） while was higher than that in group C , the difference was statistically significant （ P〈0.05 ） .HR in group D before skin incision （ T1 ） , the beginning of cardiopulmonary bypass （ T2 ） was significantly lower than that in C group, the difference was statistically significant （P〈0.05）.The cTnI levels of D group at the end of CPB （ T3 ） , 6 h after operation （ T4 ） , 12 h （ T5 ） , 24 h （ T6 ） were significantly lower than those in C group, the difference was statistically significant （P〈0.05）.IMA of group D at the end of CPB （ T3 ） , 6 h after operation （ T4 ） was significantly lower than that in C group , the difference was statistically significant （P〈0.05）.Automatic rebeating rate in D group was significantly higher than that of C group , the difference was statistically significant （ P 〈0 .05 ） .Conclusion Dexmedetomidine can stabilize the hemodynamics , reduce myocardial injury during perioperative period in patients with mitral valve replacement , has certain protective effect on myocardial .