Effect of transcutaneous electrical acupoint stimulation on postoperative olfactory memory disorder and plasma melatonin in patients with general anesthesia of sevoflurane

Abstract

To observe the effect of transcutaneous electrical acupoint stimulation (TEAS) on postoperative olfactory memory disorder in patients with general anesthesia of sevoflurane and to explore its possible mechanism. Forty patients who were scheduled to have gynecological and urological procedures under general anesthesia were randomly divided into an observation group and a control group, 20 cases in each group. The patients in the observation group were treated with TEAS (dilatational wave, 2 Hz/100 Hz) at Yingxiang (LI 20) and Yintang (GV 29) 10 min before anesthesia induction until the end of operation; the patients in the control group received general anesthesia directly. The changes of mean arterial pressure (MAP), heart rate (HR) and blood oxygen saturation (SpO2) were recorded before treatment, 30 min after operation and at the end of operation; smell identification score was measured by Connecticut Chemosensory Clinical Research Center (CCCRC) olfactory test before treatment (T0) and when Aldrete recovery score reached 10 points at the end of anesthesia (T1); the concentration of melatonin in plasma was measured by ELISA method in the two groups. The between-group differences and within-group differences of MAP, HR and SpO2 were not significant at each time point (P>0.05). Compared with T0, the score of smell identification and plasma concentration of melatonin were not significantly different at T1 in the observation group (P>0.05), however, the score of smell identification and plasma concentration of melatonin were reduced in the control group (P<0.05). At T1, the score of smell identification and plasma concentration of melatonin in the observation group were higher than those in the control group (P<0.05). TEAS could improve the postoperative olfactory memory disorder in patients with general anesthesia of sevoflurane, and its mechanism may be related to the increase of plasma concentration of melatonin.