摘要目的 探讨右美托咪啶对上肢手术患者臂丛神经阻滞及上肢缺血再灌注损伤的影响.方法 拟行腋路臂丛神经阻滞的上肢手术患者40例,性别不限,年龄18～55岁,体重45～80kg,ASA分级Ⅰ或Ⅱ级.采用随机数字表法,将患者随机分为2组(n=20),对照组(C组):神经阻滞用药为0.5%罗哌卡因30 ml;右美托咪啶组(D组):神经阻滞用药为0.5%罗哌卡因+右美托咪啶8 mg混合液30 ml.评价感觉阻滞和运动阻滞的效果,记录感觉阻滞和运动阻滞的起效时间和维持时间,于麻醉诱导前(T0)、松止血带后1、5和30 min(T1-3)时抽取术侧肘部静脉血样,测定血浆MDA和缺血修饰蛋白(IMA)的浓度,同时取术侧肘部动脉血样,行血气分析.记录术中恶心呕吐、呼吸抑制、头晕、心动过缓等并发症的发生情况.术中主诉疼痛的患者静脉注射舒芬太尼0.2μg/kg,仍因疼痛无法完成手术的患者则改为全身麻醉.结果 无一例患者使用补救用药,无一例患者更改麻醉方式,所有患者均未发生恶心呕吐、呼吸抑制、头晕、心动过缓等并发症.与C组比较,D组感觉阻滞、运动阻滞维持时间明显延长,血浆MDA和IMA的浓度明显降低,PaO2和BE升高(P＜0.05),感觉阻滞和运动阻滞的起效时间差异无统计学意义(P＞0.05);与T0时比较,两组T2、T3时血浆MDA和IMA的浓度升高,C组T1时pH值降低,两组T1时PaO2降低,T1、T2时BE降低(P＜0.05).结论 右美托咪啶不仅可增强上肢手术患者罗哌卡因臂丛神经阻滞效果,还可减轻止血带诱发的上肢缺血再灌注损伤.

abstractsObjective To investigate the effect of dexmedetomidine on brachial plexus block with ropivacaine and upper extremity ischemia-reperfusion (I/R) injury in patients undergoing upper extremity surgery. Methods Forty ASA Ⅰ or Ⅱ patients of both sexes, aged 18-55 yr, weighing 45-80 kg, scheduled forupper extremity surgery under brachial plexus block, were randomly divided into 2 groups ( n = 20 each): control group ( group C )and dexmedtomidine group (group D). In group C, brachial plexus block was performed using 0.5% ropivacaine 30 ml. In group D, brachial plexus block was performed with a mixture (30 ml) of 0.5% ropivacaine and 8 mg dexmedetomidine. The efficacy of motor and sensory block was evaluated and the onset time and duration of motor and sensory block were recorded. Venous blood samples were obtained from peripheral vein on the operated side before anesthesia induction (T0), and at 1, 5 and 30 min after tourniquet release (T1-3) to detect the plasma concentrations of MDA and ischemia-modified albumi (IMA). Arterial blood samples were also obtained at the same time points for blood gas analysis. The complications such as nausea and vomiting, respiratory depression, bradycardia and dizziness were recorded. Sufentanil 0.2 μg/kg was given as rescue medication. If the operation could not be completed, general anesthesia was used. Results There was no requirement for rescue analgesics and general anesthesia, and no complications occurred in all the patients. The duration of sensory and motor block was significantly longer, the plasma concentrations of MDA and IMA were significantly lower, and PaO2 and BE were significantly higher in group D than in group C ( P ＜ 0.05). The plasma concentrations of MDA and IMA were significantly higher at T2 and T3 in both groups, the pH value was significantly lower at T1 in group C, PaO2 at T1 and BE at T1 and T2 were significantly lower in both groups than those at T0 ( P ＜ 0.05). Conclusion Dexmedetomidine can not only enhance the efficacy of brachial plexus block with ropivacaine, but also reduce the upper extremity I/R injury caused by tourniquet in patients undergoing upper extremity surgery.