CAJ | 학술논문

目的通过评价不同剂量右美托咪定对罗哌卡因用于臂丛神经阻滞时半数有效浓度(EC50)的影响,确定右美托咪定局部用药的适宜剂量.方法择期行尺骨和桡骨骨折切开复位内固定术的患者,性别不限,年龄19～50岁,体重50 ～ 80 kg,ASA分级Ⅰ或Ⅱ级,拟在超声引导下行腋路臂丛神经阻滞.采用随机数字表法,将其分为4组:对照组(C组)、右美托眯定0.4、0.6、0.8 μg/kg组(D1组、D2组和D3组),C组神经阻滞用药仅为罗哌卡因,D1-3组神经阻滞用药为罗哌卡因和相应剂量右美托咪定的混合液.以臂丛支配区痛觉消失作为阻滞有效的标准,局麻药容量为40 ml,采用序贯法确定罗哌卡因浓度,初始浓度为0.4％,相邻浓度的比值为1.0,阻滞有效时采用低一级浓度,否则采用高一级浓度,直至每组出现第7个交叉点.以各交叉点罗哌卡因浓度的均数作为罗哌卡因用于臂丛神经阻滞的EC50.记录臂丛神经阻滞有关不良事件、心血管不良事件和镇静过度的发生情况.结果 C组、D1组、D2组和D3组入选病例分别为20、22、24、19例;与C组比较,D2组和D3组罗哌卡因用于臂丛神经阻滞的EC50降低(P＜0.05),D1组罗哌卡因用于臂丛神经阻滞的EC50差异无统计学意义(P＞0.05).D1组未见不良事件发生,D2组心动过缓发生率为17％,但是一过性的;D3组心动过缓发生率为58％,低血压发生率为32％,且需要特殊处理,镇静过度发生率为10％.结论混合罗哌卡因用于臂丛神经阻滞时右美托咪定的适宜剂量为0.6 μg/kg.
목적 통과평개불동제량우미탁미정대라고잡인용우비총신경조체시반수유효농도(EC50)적영향,학정우미탁미정국부용약적괄의제량.방법 택기행척골화뇨골골절절개복위내고정술적환자,성별불한,년령19～50세,체중50 ～ 80 kg,ASA분급Ⅰ혹Ⅱ급,의재초성인도하행액로비총신경조체.채용수궤수자표법,장기분위4조:대조조(C조)、우미탁미정0.4、0.6、0.8 μg/kg조(D1조、D2조화D3조),C조신경조체용약부위라고잡인,D1-3조신경조체용약위라고잡인화상응제량우미탁미정적혼합액.이비총지배구통각소실작위조체유효적표준,국마약용량위40 ml,채용서관법학정라고잡인농도,초시농도위0.4％,상린농도적비치위1.0,조체유효시채용저일급농도,부칙채용고일급농도,직지매조출현제7개교차점.이각교차점라고잡인농도적균수작위라고잡인용우비총신경조체적EC50.기록비총신경조체유관불량사건、심혈관불량사건화진정과도적발생정황.결과 C조、D1조、D2조화D3조입선병례분별위20、22、24、19례;여C조비교,D2조화D3조라고잡인용우비총신경조체적EC50강저(P＜0.05),D1조라고잡인용우비총신경조체적EC50차이무통계학의의(P＞0.05).D1조미견불량사건발생,D2조심동과완발생솔위17％,단시일과성적;D3조심동과완발생솔위58％,저혈압발생솔위32％,차수요특수처리,진정과도발생솔위10％.결론 혼합라고잡인용우비총신경조체시우미탁미정적괄의제량위0.6 μg/kg.
Objective To determine the optimum dose of dexmedetomidine administered locally through evaluating the effects of different doses of dexmedetomidine on the median effective concentration (EC50) of ropivacaine for brachial plexus block.Methods American Society of Anesthesiologists physical status Ⅰ or Ⅱ patients of both sexes, aged 19-50 yr, weighing 50-80 kg, scheduled for elective ulna and radius fracture open reduction and internal fixation, requiring ultrasound-guided axillary brachial plexus block, were randomly assigned into 4 groups using a random number table: control group (group C) and dexmedetomidine 0.4, 0.6 and 0.8 μg/kg groups (D1 , D2 and D3 groups).Axillary brachial plexus block was performed only with ropivacaine in group C.In D1-3 groups, axillary brachial plexus block was performed with the mixture of ropivacaine and dexmedetomidine 0.4, 0.6 and 0.8 μg/kg, respectively.The effective block was defined as complete loss of pain sensation in the areas innervated by the brachial plexus.The volume of local anesthetics was 40 ml.The concentration of ropivacaine was determined by up-and-down technique.The initial concentration was 0.4％ and the ratio between the two successive concentrations was 1.0.If the block was effective, the next patient received a lower dose of ropivacaine;or conversely if ineffective, a higher dose was given in the next patient.At least 7 independent crossover pairs were observed in each group.The EC50 of ropivacaine was the mean of the concentration of ropivacaine of each crossover pair.The occurrence of brachial plexus block-related adverse events, adverse cardiovascular events and over-sedation was recorded.Results In C, D1, D2 and D3 groups, 20, 22, 24 and 19 patientswere enrolled, respectively.Compared with group C, the EC50 of ropivacaine was significantly decreased in D2 and D3 groups, and no significant change in the EC50 of ropivacaine was found in group D1.No patients developed adverse events in group D1.The incidence of bradycardia was 17％, but it was transient in group D2.In group D3, the incidence of bradycardia and hypotension was 58％ and 32％, respectively, and they required special treatment, and the incidence of over-sedation was 10％.Conclusion The optimum dose of dexmedetomidine is 0.6 μg/kg when mixed with ropivacaine for brachial plexus block.