右美托咪定对心脏瓣膜置换术患者的心肌保护作用

The effects of dexmedetomidine on hemodynamics and myocardial reperfusion injury in patients undergoing cardiac valve replacement surgery

目的观察右美托咪定对心脏瓣置换术患者的心肌保护作用。方法风湿性心脏病行二尖瓣置换术患者30例，均择期全麻CPB下手术，年龄18-65岁，ASAⅡ或Ⅲ级。采用随机数字表法均分为右美托咪定组（D组）和生理盐水组（C组）。麻醉诱导后D组开始静注右美托咪定0．5μg／kg，然后静脉持续泵入0．5μg·kg^-1·h^-1至手术结束；C组静注等量生理盐水。记录用药前（T0）、用药后即刻（T1）、切皮后（T2）、劈胸骨后（L）、CPB前（T4）、停CPB后10min（T0）、手术结束（T6）的MAP和HR。于T0、T5、T6、术后6h（T7）、24h（T8）抽取中心静脉血ELISA法检测心型脂肪酸结合蛋白（H—FABP）、肌酸激酶（CK—MB）、肌钙蛋白I（cTnI）浓度。结果与T0时比较，T2、T3时两组MAP明显升高，T1、T2和T4时D组HR明显减慢，而T5、T6时两组HR明显增快（P〈0．05）。与C组比较，T3时D组MAP明显降低、T4时MAP明显升高（P〈0．05），T1～T3时HR明显减慢（P〈0．05）。与T0时比较，T5～T8时两组血清H—FABP、CK-MB和cTnI浓度明显升高（P〈0．05）。与C组比较，T5～T8时D组血清H—FABP浓度，T7、T8时CK—MB和cTnI浓度明显降低（P〈0．05）。结论麻醉诱导后给予0．5μg／kg负荷量右美托咪定，随后持续静脉输注0．5μg·kg^-1·h^-1，可维持体外循环前血压稳定，减轻CPB至术后24h心肌损伤。

Objective To investigate the effects of dexmedetomdine infusion on blood pressure, heart rate and myocardial reperfusion injury in patients undergoing cardiac valve replacement surgery. Methods Thirty patients （ASA Ⅱ or Ⅲ ）, aged 18-65 yrs, undergoing cardiac vavle replacement surgery were randomized into 2 groups （n= 15 each） ： control group （group C） and dexmedetomidine group（group D）. Anesthesia was induced with midazolam （0. 05 mg/kg）, sufentanyl（1 μg/kg）,etomidate（0.3 mg/kg） and rocuronium（0.6 mg/kg） in both groups. In group D, a 0.5μg/kg bolus dose of dexmedetomidine was administered 10 min after the induction of anesthesia, followed by a 5μg·kg^-1·h^-1 infusion until the end of operation, while in group C equal volume of normal saline was in- fused instead of dexmedetomidine. HR and MAP were recorded before dexmedetomidine was administered（T0）, after bolus dexraedetomidine was administered （T1）, after surgical incision （T2）, post- sternotomy （T3）, before CPB（T4 ）, after CPB（T5 ） and at the end of operation（T6 ）. Venous blood samples were taken at T0, T5, T6, at 6 h （T7） and 24 h （T8） after operation for measurement of serum concentration of H-FABP, CK-MB and cTnI by ELISA. Results MAP was significantly higher at T1 than To in group D（P〈0. 05） ,while in group C MAP was significantly higher at T2 and T3 than To （P〈0.05）, and was higher than group D at T3. H-FABP, CK-MB and cTnI were significantly higher at T5 ,T6, 6 h and 24 h after operation than To in both groups. Compared with group C, H-FABP were significantly lower at T5-T8 after operation, and CK-MB and eTnI were significantly lower at 6 h and 24 h after operation in group D （P〈0. 05）. Conclusion Dexmedetomidine 0.5 μg/kg bolus followed by 0. 5μg·kg^-1·h^-1 infusion during operation can maintain hemodynamics more stable and pro- tect myocardium from reperfusion injury in patients undergoing cardiac valve replacement surgery.