title: Effect of ephedrine on auditory-evoked potentials during light general anaesthesia.
abstract: Ephedrine, a sympathomimetic drug, may stimulate the central nervous system via its amphetamine-like effect under light general anaesthesia. We compared the effect of ephedrine on auditory-evoked potentials with that of etilefrine, a sympathomimetic drug that lacks an amphetamine-like effect, in patients undergoing abdominal surgery under general anaesthesia with 67% nitrous oxide in oxygen and epidural blockade. Ephedrine (0.08 mg x kg-1 intravenously) significantly decreased the latencies of Nb and P1 from 49.5 (4.2) [mean (SD)] and 63.9 (9.1) ms to 45.9 (4.2) and 59.0 (9.9) ms, respectively; whereas etilefrine (0.02 mg x kg-1 intravenously) caused no significant changes in these potentials. In addition, the latencies of Nb and P1 before drug administration were positively correlated with patient age. These findings suggest that ephedrine can cause excitation of the central nervous system during light general anaesthesia, and that auditory-evoked potentials may be a sensitive indicator of the depth of anaesthesia.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Oita Medical University, Hasama-machi, Oita 879-5593, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Mori
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.forename: S
authors.initials: S
authors.lastname: Hattori
authors.forename: H
authors.initials: H
authors.lastname: Miyakawa
authors.forename: T
authors.initials: T
authors.lastname: Noguchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000768:Anesthesia, General; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004809:Ephedrine / Q000494:pharmacology*; D005039:Etilefrine / Q000494:pharmacology; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011930:Reaction Time / Q000187:drug effects; D013566:Sympathomimetics / Q000494:pharmacology*
chemical_list: D000697:Central Nervous System Stimulants; D013566:Sympathomimetics; D004809:Ephedrine; D005039:Etilefrine