0.5%罗哌卡因超声引导下颈横突旁阻滞的有效容量

Effective volume of 0.5% ropivacaine for ultrasound-guided cervical transverse process block

目的研究超声引导下颈4(C4)、颈5(C5)、颈6(C6)横突旁阻滞使用0.5%罗哌卡因的50%有效容量和95%有效容量。方法 30例拟行锁骨、肩部或肱骨近端手术患者,超声引导下行C4、C5、C6横突旁阻滞,使用Dixon序贯法实验出0.5%罗哌卡因在相应颈椎横突旁阻滞50%患者有效容量(EAV50)和95%患者有效容量(EAV95)。0.5%罗哌卡因起始容量皆定为3 ml,如麻醉成功,则下一例患者相同颈椎横突旁阻滞容量在原基础上增加0.3 ml,如麻醉失败,下一例患者容量减少0.3 ml。采用Probit概率单位回归法分别计算超声引导下C4、C5、C6横突旁阻滞使用0.5%罗哌卡因的EAV50和EAV95以及相应95%可信区间。结果 1超声引导下C4横突旁阻滞,0.5%罗哌卡因的EAV50为1.746 ml,95%CI:1.583,1.869;EAV95为2.255 ml,95%CI:2.035,2.778;2超声引导下C5横突旁阻滞,0.5%罗哌卡因的EAV50为1.901 ml,95%CI:1.727,2.075;EAV95为2.456 ml,95%CI:2.220,3.015;3超声引导下C6横突旁阻滞,0.5%罗哌卡因的EAV50为3.339 ml,95%CI:3.073,3.625;EAV95为4.314 ml,95%CI:3.905,5.329;4超声引导下C6横突旁阻滞使用0.5%罗哌卡因的量效曲线相对C4、C5横突旁阻滞的量效曲线右移且平行。结论超声引导下C4、C5、C6横突旁阻滞使用0.5%罗哌卡因的EAV50分别为1.746、1.901和3.339 ml,EAV95分别为2.225、2.456和4.314 ml,C6横突旁阻滞使用0.5%罗哌卡因的容量显著多于C4、C5。

Objective To determine the 50% effective volume （EAV50） and the 95% effective volume （EAV95） of 0.5% ropivacaine for ultrasound-guided cervical transverse process block. Methods Thirty patients scheduled for clavicle, shoulder or proximal humeral surgeries were blocked with 0.5% ropivacaine for ultrasound-guided C4, C5 and C6 transverse process block. The EAV50 and EAV95 were determined by up-and-down sequential test. The starting dose of 0.5% ropivacaine was set at 3ml for every cervical transverse process, which was decreased by 0.3 ml if the block succeeded and increased by 0.3ml if the block failed. EAV50 and EAV95 were calculated by Probit Regression method. Results The EAV50 and EAV95 volumes of 0.5% ropivacaine for ultrasound-guided C4 transverse process block were 1.746 ml （95%CI ： 1.583, 1.869） and 2.255 ml （95%CI ： 2.035, 2.778）, respectively. The EAVS0 and EAV95 of 0.5% ropivaeaine for ultrasound-guided C5 transverse process block were 1.901ml （95% CI ： 1.727, 2.075） and 2.456 ml （95%CI ： 2.220, 3.015）, respectively. The EAV50 and EAV95 of 0.5% ropivacaine for ultrasound-guided C6 transverse process block were 3.339 ml （95%CI ： 3.073, 3.625） and 4.314 （95%CI ： 3.905, 5.329）, respectively. A paralleled but right-shift effective volume-effect curve was observed in 0.5% ropivaeaine for uhrasound-guided Ca transverse process block when compared to those of C4 and C5. Conclusions The EAV50 of 0.5% ropivacaine for ultrasound-guided C4, C5 and C6 transverse process block are 1.746, 1.901 and 3.339 ml, respectively. The EAV95 are 2.225, 2.456 and 4.314 ml, respectively. The effective volume of 0.5% ropivacaine for ultrasound-guided C6, transverse process block is more than that of C4 and C5 significantly.