经皮穴位电刺激对患者异丙酚麻醉诱导时镇静效应的影响

Effect of transcutaneous electrical acupoint stimulation on sedative efficacy during induction of anesthesia with propofol

目的 探讨经皮穴位电刺激（TEAS）对患者异丙酚麻醉诱导时镇静效应的影响.方法 择期行全麻下甲状腺手术患者,ASA分级Ⅰ或Ⅱ级,年龄21- 69岁,采用随机数表法分为2组：对照组（C组）和TEAS组.TEAS组给予TEAS 30 min,采用疏密波,频率2/100 Hz,波宽0.2- 0.6 ms,根据患者可耐受的程度刺激电流强度维持8- 12 mA.TEAS结束后即开始麻醉诱导.采用序贯法确定异丙酚使患者意识消失的半数有效血浆靶浓度（EC50）.异丙酚初始血浆靶浓度为3μg/ml,意识消失后第5-8分钟内每隔30 s记录BIS值,取平均值,以平均值降至50以下为阳性反应.异丙酚靶浓度的调节幅度为0.3 μg/ml.结果 C组纳入23例,TEAS组纳入25例.TEAS组异丙酚使患者意识消失的EC50为3.08 μg/ml,C组为3.70μg/ml,组间比较差异有统计学意义（P＜0.05）.结论 TEAS可增强患者异丙酚麻醉诱导时的镇静效应.

Objective To evaluate the effect of transcutaneous electrical acupoint stimulation （TEAS） on sedative efficacy during induction of anesthesia with propofol.Methods Patients,of ASA physical status Ⅰ or Ⅱ,aged 21-69 yr,scheduled for elective thyroid surgery,were randomly divided into 2 groups using a random number table：control group （group C） and TEAS group.TEAS was applied to bilateral Hegu and Neiguan acupoints for 30 min.The frequency was 2/100 Hz,wave length was 0.2-0.6 ms and the intensity was maintained at about 8-12 mA according to the current that could be tolerated.Induction of anesthesia was started at the end of TEAS.Sequential method was used to determine the median effective target plasma concentration （EC50） of propofol causing loss of consciousness in each group.The initial target plasma concentration of propofol was 3 μg/ml.BIS value was recorded every 30 s within 5-8 min after loss of consciousness and the average BIS value was calculated.It was considered to be positive response when the average BIS value was below 50.The target concentration of propofol was decreased/increased by 0.3 μg/ml in the next patient.Results EC50 of propofol causing loss of consciousness was 3.08 μg/ml in group TEAS,and 3.70 μg/ml in group C,and there was significant difference between the two groups.Conclusion TEAS can enhance the sedative efficacy during induction of anesthesia with propofol in the patients.