硬膜外麻醉时皮肤电传导变化的临床观察

Clinical observation of skin conductance changes during epidural anesthesia

目的探讨硬膜外麻醉时皮肤电传导(SC)基态值和反应波的变化。方法选择25例ASAⅠ或Ⅱ级下肢手术患者。记录硬膜外给药前(T0)、给予1%利多卡因5ml后5min(T1)、给予0.75%罗哌卡因10ml后5、10、15、25和45min(T2～T6)时的SC基态值(SC0)、针刺非阻滞区SC反应波的振幅差值(SC1)和痛觉阻滞区的SC反应波的振幅差值(SC2)。使用ROC曲线、逻辑回归分析评价SC反应波的振幅差值区分痛觉阻滞区和非阻滞区的准确性。结果与T0时比较,T3～T6时的SC0及SC1的均值明显降低(P<0.05),T1～T6时SC2明显低于SC1(P<0.05)。SC反应波的振幅差值ROC曲线下面积为0.928±0.017(P<0.01),特异性与敏感性分别为78%和88%,预测整体准确率84%。结论 SC基态值及反应波振幅差值的变化对定位硬膜外麻醉平面有一定指导作用。

Objective To investigate the changes of basic value and amplitude of the waves of skin conductance （SC） during epidural anesthesia. Methods Twenty-five ASA I or II patients received selective lower limb surgery were included in this study. The basic value （SC0） of SC and the amplitude of the waves in non-blocked areas （SCI） and blocked areas （SC4） were recorded at the following time points： before epidural local anesthetic injection （To）, 5 min after 5 ml of 1% lidocaine injection（T1 ）, 5, 10, 15, 25 and 45 min （Tz-T6） after 0. 75 % ropivacaine 10 ml injection. Receiver operation characteristic curve （ROC） and logistic regression were used to assess the sensitivity and specificity and predict the accuracy of sensory block during epidural anesthesia. Results Compared with To, the mean of SC0 and SC1 were lower at T3-T6 （P〈0.05）. The mean of SCz at T1-T6 were significantly decreased than SC1 （P〈0. 05）. The area under the ROlE of SC was 0..928±0. 017 while the sensitivity and the specificity were 88 % and 78 %, respectively. The total prediction accuracy was 84%. Conclusion The changes of basic value and the amplitude of waves of SC have a guiding role on the positioning of sensory block during epidural anesthesia.