右美托咪定行超声引导下臂丛神经阻滞时罗哌卡因的半数有效剂量研究

Study on median effective dose of ropivacaine combined with dexmedetomidine for ultrasound-guided interscalene brachial plexus block for arthroscopic shoulder surgery

目的:探索行超声引导下臂丛神经阻滞联合应用右美托咪定时0.375%罗哌卡因的半数有效剂量(ED50)。方法:选取择期行肩关节镜手术的患者30例,性别不限,美国麻醉医师协会(American Society of Anesthesiologists,ASA)分级Ⅰ级或Ⅱ级。患者入手术室即开始泵注右美托咪定(0.5μg·kg^-1·h^-1),于超声引导下行肌间沟臂丛阻滞,给予0.375%罗哌卡因首剂量100mg,后各相邻患者剂量之间的比值为1.2。采用改良序贯法计算0.375%罗哌卡因的ED50及95%可信区间。观察患者的麻醉效果及有无药品不良反应(ADRs)发生。结果:肩关节镜手术患者行超声引导下臂丛神经阻滞复合右美托咪定时0.375%罗哌卡因的ED50为19ml,95%可信区间为17.5~21.5ml。ADRs观察发现1例霍纳(Horner)综合征,1例低心率、低血压事件。结论:肩关节镜手术患者行超声引导下臂丛神经阻滞时复合右美托咪定,可减少罗哌卡因的剂量,且麻醉效果好,无严重ADRs发生。

Objective : To investigate the median effective dose(ED 50 ) of 0.375% ropivacaine combined with dexmedetomidine for ultrasound-guided interscalene brachial plexus block(ISBPB) of the patients undergoing arthroscopic shoulder surgery.Methods : Thirty patients who were classified as grade Ⅰ or Ⅱ according to American Society of Anesthesiologists(ASA) and underwent shoulder arthroscopic surgery were enrolled for the study regardless of gender.The patients started to have the pumping of dexmedetomidine (0.5 μg·kg^-1 ·h^-1 ) for ultrasound-guided interscalene brachial plexus block in arthroscopic shoulder surgery when they were admitted into the operating room.The starting dose of 0.375% ropivacaine was 100 mg for the first patient and the ratio between adjacent patients' doses was 1.2.The ED 50 and 95% confidence interval of ropivacaine was calculated by up-and-down methodology.The anesthetic effect and adverse drug reactions(ADRs) of the patients were observed closely.Results : The ED 50 of 0.375% ropivacaine combined with dexmedetomidine for ultrasound-guided interscalene brachial plexus block for arthroscopic shoulder surgery was 19 ml and 95% confidence interval was 17.5-21.5 ml.There was one case of Horner syndrome and one case of hypotensive bradycardia event during surgery.Conclusion : Ropivacaine combined with dexmedetomidine in ultrasound-guided brachial plexus block could reduce the dosage of ropivacaine in patients undergoing shoulder arthroscopic surgery,with good anesthetic effect and without severe ADRs.