THE EFFECT OF LOCATION OF TRANSCUTANEOUS ELECTRICAL NERVE-STIMULATIONON POSTOPERATIVE OPIOID ANALGESIC REQUIREMENT - ACUPOINT VERSUS NONACUPOINT STIMULATION

Transcutaneous electrical nerve stimulation (TENS) has been used as a complementary (supplemental) therapy to opioid analgesics for pain rel ief after surgery. Simultaneous stimulation ata classical Chinese acup oint site and periincisional dermatomes significantly decreases the po stoperative analgesic requirement. This sham-controlled study was de s igned to assess the relative effectiveness of acupoint versus nonacupo int stimulation on the postoperative hydromorphone (HM) requirement, t he incidence of opioid-related side effects, and the overall recovery profile. One hundred women undergoing total abdominal hysterectomy or myomectomy procedures with a standardized general anesthesia were rand omly assigned to one of four postoperative analgesic treatment regimen s (n = 25 each): Group I = sham-TENS (no electrical current) at the Zu sanli (ST36) acupoints, Group II = nonacupoint-TENS at the shoulders, Group III = dermatomal-TENS at the level of the surgical incision, and Group IV = acupoint-TENS at the Zusanli acupoints. The frequency of T ENS was set in the standard dense-and-disperse mode of 2/100 Hz. The i ntensity of stimulation was set at 0 mA for patients in Group I and at 9-12 mA for patients in Groups IT, III, and IV. A patient-controlled analgesia (PCA) device programmed to deliver bolus doses of HM 0.2-0.4 mg IV on demand with a minimal lockout interval of 10 min was used to quantify the postoperative opioid analgesic requirement. Standard 100 -mm visual analog scales were used to assess pain, as well as sedation , fatigue, and nausea, at specific intervals after surgery. The number s of PCA demands and delivered bolus doses, requirements for supplemen tal medication, and any opioid-related side effects were recorded. In the first 24 h postoperatively, the opioid requirements in Groups III and IV were decreased by 37% and 39%, respectively, compared with the control (sham) group and 35% and 38%, respectively, compared with Grou p II. The duration of PCA usage and the incidences of nausea and dizzi ness were also significantly de creased in Groups III and IV compared with Groups I and II. We conclude that periincisional dermatomal and Z usanli acupoint stimulation were equally effective in decreasing the p ostoperative opioid analgesic requirement and in reducing opioid-relat ed side effects. Both of these positions were more effective than the nonacupoint (shoulder) location. Implications: The location of the sti mulating electrodes seems to be an important determinant of the effica cy of transcutaneous electrical nerve stimulation in decreasing the ne ed for opioid analgesics in the postoperative period. This study demon strates that transcutaneous electrical nerve stimulation applied at th e dermatomal level of the skin incision is as effective as Zusanli acu point stimulation, and both were more effective than stimulation at a nonacupoint (shoulder) location.