Effect of Transcutaneous Acupoint Electrical Stimulation on Half Effective Dose of Midazolam-induced Consciousness Loss in Elderly Patients
GUO Yan-hui,ZHAO Chong-fa
Department of Anesthesiology, Tianjin Haihe Hospital, Tianjin(300350), China
Abstract:
Objective To investigate the effect of transcutaneous acupoint electrical stimulation (TEAS) on half effective dose (ED50) of consciousness loss in elderly patients induced by midazolam. Methods Elderly patients undergoing lower limb surgery under elective spinal anesthesia in our hospital were randomly divided into two groups: TEAS group and control group, and given intraspinal anesthesia. In TEAS group, midazolam was injected intravenously after 20 min of TEAS at Hegu and Neiguan acupoints on both sides. The patients in the control group were given electrodes at corresponding acupoints and connected stimulator without electric stimulation. Awareness disappearance was judged by OAA/S score less than 2. The dose of midazolam was determined by sequential method. The initial dose was 40 μg/kg and the adjacent dose ratio was 1:1.1. The test was terminated when there were 7 crosses between yin and yang. Sequential formula method was used to calculate the ED50 and 95% confidence interval of consciousness loss induced by midazolam. Results The ED50 and 95% confidence interval of midazolam in stimulation group were 40.5 μg/kg (95% CI: 28.1–58.2 μg/kg) and 47.7 μg/kg (95% CI: 33.1–68.9 μg/kg) respectively. There were significant differences between the two groups (P<0.05). Conclusion TEAS can reduce ED50 in elderly patients with consciousness loss caused by midazolam.
