剖宫产术患者不同比重罗哌卡因腰麻半数有效剂量的比较

目的 比较剖宫产术患者不同比重罗哌卡因腰麻的半数有效剂量(ED50).方法 择期脊椎-硬膜外联合麻醉下行剖宫产术的单胎足月初产妇40例,年龄20～40岁,采用随机数字表法,将其随机分为2组(n=20):重比重罗哌卡因组(HR组)和轻比重罗哌卡因组(LR组).经L2.3间隙行蛛网膜下腔穿刺,2组第1例患者局麻药的初始剂量均为9mg,HR组和LR组分别给予0.5％重比重和0.5％轻比重罗哌卡因,根据腰麻是否有效按照序贯法确定下一例患者的剂量,剂量间隔为1mg.采用概率单位法计算不同比重罗哌卡因腰麻的ED50及其95％可信区间(CI).结果 0.5％重比重和0.5％轻比重罗哌卡因腰麻的ED50分别为9.34 mg(95％CI 8.34～10.46 mg)和9.64 mg(95％CI 8.90～10.44 mg),二者ED50比较差异无统计学意义(P＞0.05).结论 剖宫产术患者0.5％重比重和0.5％轻比重罗哌卡因腰麻的ED50分别为9.34和9.64 mg,比重因素对罗哌卡因腰麻效果无影响.

Median effective dose of intrathecal hyperbaric and hypobaric ropivacaine for cesarean section

Objective To determine the median effective dose (ED50) of intrathecal (IT) hyperbaric and hypobaric ropivacaine for elective cesarean section.Methods Forty parturients aged 20-40 yr at full term undergoing elective cesarean section under combined spinal-epidural anesthesia were randomized to receive IT 0.5 ％ hyperbaric (group HR) and hypobaric ropivacaine (group LR) ( n =20 each).The initial dose was 9 mg and the dose was increased/decreased by 1 mg in the next parturient using an up-and-down sequential allocation technique.Analgesia was considered acceptable if adequate analgesia reached T7 or higher in response to pin prick until 20 min after IT ropivacaine and no supplemental epidural analgesic was required during the operation.ED50 and 95％confidence interval (CI) were calculated.Results The ED50 and 95 ％ CI were 9.34 mg (95 ％ CI 8.34-10.46mg) for 0.5％ hyperbaric ropivacaine and 9.64 mg (95％ CI 8.90-10.44 mg) for 0.5％ hypobaric ropivacaine.Conclusion Baricity has no effect on the efficacy of IT ropivacaine for cesarean section.