The Timing of Acupuncture Stimulation Does Not Influence Anesthetic Requirement

The Timing of Acupuncture Stimulation Does Not Influence Anesthetic Requirement
Published in final edited form as:
Anesth Analg. 2005 February
Grigory Chernyak, M.D.,* Papiya Sengupta, M.D.,? Rainer Lenhardt, M.D.,# Edwin Liem, M.D.,# Anthony G. Doufas, M.D., Ph.D.,# Daniel I. Sessler, M.D.,‹ and Ozan Ak¡a, M.D.#
Anesthesia & Analgesia
PubMed Central

*Resident, Department of Anesthesiology and Perioperative Medicine, University of Louisville.

?Research Fellow, Outcomes ResearchÙ Institute, University of Louisville.

#Assistant Professor, Outcomes ResearchÙ Institute and Department of Anesthesiology and Perioperative Medicine, University of Louisville.

‹Vice Dean for Research, Associate Vice President for Health Affairs, Director Outcomes ResearchÙ Institute, Lolita & Samuel Weakley Distinguished University Research Chair, Professor of Anesthesiology & Perioperative Medicine and Pharmacology, University of Louisville
Address correspondence to Daniel I. Sessler, M.D.: Outcomes ResearchÙ Institute, 501 E. Broadway, Louisville, KY 40202. Telephone: 502-852-2553. Fax: 502-852-2610. E-mail: Sessler@louisvill.edu. On the world wide web: www.or.org, .

The publisher's final edited version of this article is available free at Anesth Analg.
See commentary in volume 101 on page 927.

Abstract

Studies suggest that acupuncture is more effective when induced before induction of general anesthesia than afterwards. We tested the hypothesis that electro-acupuncture initiated 30 minutes before induction reduces anesthetic requirement more than acupuncture initiated after induction. Seven volunteers were each anesthetized with desflurane on 3 study days. Needles were inserted percutaneously at 4 acupuncture points thought to produce analgesia in the upper abdominal area and provide generalized sedative and analgesic effects: Zusanli (St36), Sanyinjiao (Sp6), Liangqiu (St34), and Hegu (LI4). Needles were stimulated at 2-Hz and 10-Hz, with frequencies alternating at two-second intervals. On Preinduction day, electro-acupuncture was started 30 minutes before induction of anesthesia and maintained throughout the study. On At-induction day, needles were positioned before induction of anesthesia, but electro-acupuncture stimulation was not initiated until after induction. On Control day, electrodes were positioned near the acupoints, but needles were not inserted. Noxious electrical stimulation was administered via 25-G needles on the upper abdomen (70 mA, 100 Hz, 10 seconds). Desflurane concentration was increased 0.5% when movement occurred and decreased 0.5% when it did not. These up-and-down sequences continued until volunteers crossed from movement to no-movement 4 times. The P50 of logistic regression identified desflurane requirement. Desflurane requirement was similar on the Control (5.2±0.6%, mean±SD), Preinduction (5.0±0.8%), and At-induction (4.7±0.3%, P=0.125) days. This type of acupuncture is thus unlikely to facilitate general anesthesia or decrease the need for anesthetic drugs.

Keywords: Anesthetic technique: Acupuncture, Electro-acupuncture, Potency: anesthesia requirement, Anesthetics, volatile: desflurane

Introduction

Acupuncture may alleviate postoperative nausea and vomiting (1) improve postoperative analgesia (2), and reduce intraoperative opioid requirement (3). Three studies have evaluated the use of acupuncture to reduce volatile anesthetic requirements. The first used electro-acupuncture of a single auricular acupoint and identified a statistically significant 11% reduction in anesthetic requirement (4). The second used needles at four auricular acupoints and identified a statistically significant 8% reduction in anesthetic requirement (5). The third study, which stimulated three acupoints on the leg, failed to reduce anesthetic requirement (6). In each of the three studies, (4-6) acupuncture was initiated after induction of general anesthesia to maintain complete double blinding. (These studies were arguably the first fully double-blinded acupuncture trials.) Nonetheless, aspects of this design might have obscured the potential influence of acupuncture on anesthetic requirement.

De-Qi is a typical sensation that is associated with proper acupuncture needle positioning. Patients variously report it as a soreness, numbness, warmth, heaviness, or distention around the area where the needle is inserted. De-Qi appears to be a slow pain sensation conducted by non-myelinated c fibers. Many practitioners consider this sensation to be crucial in achieving the effect of acupuncture (7). Because the De-Qi sensation cannot be elicited during anesthesia, the first limitation of previous studies of acupuncture and anesthetic requirement is that the needles may have been suboptimally positioned.

The endorphin hypothesis suggests that acupuncture activates type II muscle afferents that send signals to sites in the brain to release endorphins (8). These endorphins then suppress pain signals in the dorsal horn of the spinal cord. Emotional aspects of pain are also suppressed by endorphins acting in the limbic system. General anesthesia can block or attenuate these pathways (9,10), thus reducing the efficacy of subsequent acupuncture. There is considerable evidence to support this theory. For example, stimulation of the P6 acupuncture point reduces the risk of postoperative nausea and vomiting (11-13), except when acupuncture is started after induction of anesthesia (14-16).

The second limitation of previous studies of acupuncture and anesthetic requirement is that pre-existing general anesthesia may itself reduce the efficacy of acupuncture. Initiation of acupuncture after induction of general anesthesia has the advantage of permitting fully double-blinded trials. However, available evidence suggests that the efficacy of acupuncture Û whether for analgesia or antiemetic effect Û may be diminished when it is initiated after induction of general anesthesia. We, therefore, tested the hypothesis that acupuncture started 30 minutes before induction of anesthesia reduces anesthetic requirement more than acupuncture started at induction of anesthesia. We chose 30 minutes before induction because it takes ≈20 minutes after needle insertion to achieve maximum acupuncture analgesia (17).

Please visit the website to view the article in its entirety.