Transcutaneous electrical stimulation of an auricular acupuncture point decreases anesthetic requirement.
BACKGROUND
German anesthesiologists have long used transcutaneous electrical stimulation of an acupuncture point near the tragus to reduce anesthetic requirement in unblinded and uncontrolled trials. This is known as auricular electrically stimulated analgesia. The authors therefore tested the hypothesis that auricular electrically stimulated analgesia reduces anesthetic requirement.


METHODS
In a randomized, double-blind, crossover trial, volunteers were anesthetized twice with desflurane. Electrical stimulation of an auricular acupuncture point in the vicinity of the tragus was used on 1 randomly assigned day, and no electrical stimulation of the same point was used on the other study day. Treatment consisted of bilateral electrical stimulation of the lateralization control point, 3 cm anterior to the tragus. The 10-mA current was set to 299 Hz on the dominant side of the face and to 149 Hz on the contralateral side. Anesthetic requirement was determined by the Dixon up-and-down method and was defined by the average desflurane concentration required to prevent purposeful movement of the extremities in response to noxious electrical stimulation.


RESULTS
Ten men and 10 women completed the protocol. Electrical stimulation of the lateralization control point reduced anesthetic requirement by 11 +/- 7% (P < 0.001), with the reduction being similar in women and men. Women required more desflurane to prevent movement on the control day than the men (5.5 +/- 1.0 vs. 4.6 +/- 0.6 vol%; P = 0.028).


CONCLUSIONS
This double-blinded trial with an objective outcome demonstrates that electrical stimulation of the lateralization control point significantly reduces anesthetic requirement.
Greif
Robert
R
Department of Anesthesia and Perioperative Care, University of California-San Francisco, San Francisco, California, USA.
Laciny
Sonja
S
Mokhtarani
Masoud
M
Doufas
Anthony G
AG
Bakhshandeh
Maryam
M
Dorfer
Leopold
L
Sessler
Daniel I
DI
D015669:Acupuncture Points; D000293:Adolescent; D000328:Adult; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D000077335:Desflurane; D004311:Double-Blind Method; D004431:Ear, External; D015671:Electroacupuncture; D004566:Electrodes; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007530:Isoflurane / Q000008:administration & dosage / Q000031:analogs & derivatives; D008297:Male; D010147:Pain Measurement
D018685:Anesthetics, Inhalation; D000077335:Desflurane; D007530:Isoflurane