硬膜外麻醉下皮肤电传导率判定麻醉平面的观察

The observation of sensory block in epidural anesthesia in evaluating the clinical efficacy and accuracy by monitoring skin conductance

目的探讨在硬膜外麻醉皮肤电传导率（skin conductance,SC）的变化区分痛觉阻滞区与非阻滞区的准确性。方法择期美国麻醉医师协会（The American Society of Anesthesiologists,ASA）分级Ⅰ~Ⅱ级、硬膜外麻醉下行下肢手术的病人25例,选择L2~3间隙硬膜外穿刺置管,穿刺成功后连接SC监测仪。收集5个时点数据：基础值（G0）,试验剂量1%利多卡因5 ml后5 min（G1）,负荷剂量0.75%的罗哌卡因8 ml后5 min（G2）、10 min（G3）、15 min（G4）。每个时点记录SC的基础值（SC0）,电刺激下G1~G4痛觉阻滞区（SC1）与非痛觉阻滞区（SC2）的SC的改变值。统计方法采用ROC曲线（Receiver Operating Characteristic）处理。结果与基础值G0相比,G1~G4时点SC0、SC1、SC2的均值逐渐降低,SC1、SC2的总体均值为1.82μS与0.38μS,两者相比差异有统计学意义（P〈0.05）。ROC曲线下面积为0.952,与0.5相比,有统计学意义（P〈0.01）,SC改变值为0.74μS时判定痛觉阻滞平面的特异性为82%,敏感性为90%。结论 SC的变化对区分硬膜外麻醉下痛觉阻滞区与非阻滞区具有较高价值。

Objective To evaluate the clinical efficacy and accuracy by monitoring skin conductance（SC） to judge the pain and non-pain sensory block region in epidural anesthesia.Methods Twenty five American society of anesthesiologists ASA Ⅰ～Ⅱ patients with normal communicating ability undergoing elective surgery were enrolled in this study.The patients were premedicated.After each patients were carried out an epidural catheter placed at L2～3 interspace,SC were monitored and recorded data.1% lidocaine 5 ml were given through epidural catheter as a test dose.After correct placement of epidural catheter was confirmed five minutes later,0.75% ropivacaine 8 ml were injected into epidural space.A total of five groups of data,they were given prior to local anesthestic（G-0）,1% lidocaine 5 min（G-1）,0.75% ropivacaine 5 min（G-2）,10 min（G-3） and 15 min（G-4）.Each group were recorded the basis of skin conductance value（SC-0） and the change value in epidural anesthesia plane up（SC-1） and down（SC-2） by reduplicate electric stimulation modus.Receiver operation characteristic（ROC） curve were used to analysis the sensitivity and specificity and predict the accurateness of the plane of sensory block in epidural anesthesia.Results Compared with the G-0,the mean of SC-0,SC-1 and SC-2 in other group continued to decrease.The overall average value of SC-1 and SC-2 were 1.82 micro Siemens（μS） and 0.38 μS in epidural anesthesia plane up and down correspondingly.The area under the ROC curve was in 0.952 and had significant differences from 0.5（P0.01）.When the value of SC changed been 0.74 μS,the sensitivity and the specificity were 90% and 82% respectively.Conclusion The value of SC change had high accurateness in distinguishing between pain and non-pain sensory block region.