Transcutaneous electrical nerve stimulation is superior to opioid for microlaryngeal endoscopic surgery

Abstract

S238 INTRODUCTION: Transcutaneous electrical nerve stimulation (TENS) is commonly used for stimulation therapy of pain. The aim of this study was to evaluate the effect of TENS for microlaryngeal endoscopic surgery. METHODS: After obtaining approval from the Protection of Human Subjects Committee of Jikei University Hospital and informed consent from each patient, 33 adult patients (ASA physical status I or II), undergoing microlaryngeal endoscopic surgery were studied. Each patient was randomly assigned to one of three groups (general anesthesia [G] [n=11], general anesthesia with opioid [O] [n=11], and general anesthesia with TENS [T] [n=11]). G consisted of simple anesthesia with isoflurene (1-1.5%), nitrous oxide (67%) and oxygen (33%). O was the same as G but with butorphanol (0.04 mg/kg) given intravenously. T was the same as G but with TENS employing Silver Spike Point (SSP) electrodes (Nihon Medix, Japan) for continuous stimulation (5 Hz) with Trimix 1 (Nihon Medix, Japan) during anesthesia. Pore sites were bilateral Gokoku (LI4) and Ashisanri (S36). The voltage level was that immediately before each patient felt subjective pain before the induction of anesthesia. We measured blood pressure (BP) and heart rate (HR) before [baseline] and after insertion of the laryngeal scope, and the time to extubation of the trachea (ET), and we counted the number of cases in whom systolic BP increased to more than 180 mmHg. Results were analyzed using ANOVA followed by a Bonferroni T-test and chi-square test. P<0.05 was considered to be significant. RESULTS: There were no significant differences among the groups in age, height, body weight and anesthetic time. T showed a significantly decreased HR compared with G and O. O showed a significantly increased ET compared with G and T. BP did not change significantly in each group, but T showed a significant decrease of high BP(>or=to180 mmHg) compared with G and O (Table 1).Table 1DISCUSSION: TENS was superior to butorphanol in decreasing HR and BP in microlaryngeal endoscopic surgery.