Original Contributions *Assistant Professor of Anaesthesia †Fellow in Obstetric Anaesthesia ‡Professor of Anaesthesia §Associate Professor of Anaesthesia Address correspondence to Dr. Tsen at the Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, 75 Francis St., Boston, MA 02115, USA. E-mail: ltsen@zeus.bwh.harvard.edu TENS units were provided by Staodyn, Inc, Longmont, CO. Departmental support was used for the completion of this study. Received for publication May 4, 2001; revised manuscript accepted for publication August 28, 2001. Transcutaneous Electrical Nerve Stimulation Does Not Augment Epidural Labor Analgesia Lawrence C. Tsen, MD,* John Thomas, MD,† Scott Segal, MD,* Sanjay Datta, MD,‡ Angela M. Bader, MD§ Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, and Department of Anaesthesia, Harvard Medical School, Boston, MA Study Objective: To evaluate whether transcutaneous electrical nerve stimulation (TENS) can increase the quality and duration of an initiation dose of bupivacaine used for the establishment of epidural labor analgesia. Design: Randomized, double-blind study. Setting: Tertiary-care academic medical center. Patients: 40 ASA physical status I and II parturients in early, active spontaneous labor with a singleton, vertex term fetus, and requesting analgesia. Interventions: A standardized epidural technique with either an active or inactive TENS unit was performed. Before epidural placement, TENS intensity thresholds were determined with electrodes placed over the paraspinus muscles at T 10 –L 1 , and S 2 –S 4 ; TENS settings for mode, cycle, and pulse width were standardized. Measurements: Data were collected at timed intervals on pain as measured by visual analog scale (VAS), sensory level (pinprick), motor blockade (Bromage score), cervical dilation, and duration of analgesia. Main Results: The duration of analgesia produced by the initial dose of epidural bupivacaine did not differ between groups (TENS turned off 82.3  26 [mean  SD] vs. TENS activated 80.7  40 min, p = 0.88). Kaplan-Meier survival analysis and Mantel-Cox log rank analysis showed no difference between the two treatments (p = 0.75). No difference in the quality of analgesia was observed between the two groups. Conclusions: In healthy laboring parturients, the application of a TENS unit did not alter the quality or duration of an initiation dose of bupivacaine utilized for the establishment of epidural labor analgesia. © 2001 by Elsevier Science Inc. Keywords: Analgesia: labor; anesthesia: obstetric; anesthetic techniques: combined spinal epidural; equipment and supplies: transcutaneous electrical nerve stimulation. Introduction The use of local anesthetics in the epidural space is one of the most commonly performed methods for labor analgesia because of the quality, versatility, and Journal of Clinical Anesthesia 13:571–575, 2001 © 2001 Elsevier Science Inc. All rights reserved. 0952-8180/01/$–see front matter 655 Avenue of the Americas, New York, NY 10010 PII S0952-8180(01)00332-4