title: Anesthetic effects on motor evoked potentials in dogs.
abstract: The effects of the various anesthetic agents on the production of transcranial magnetic motor evoked potentials (tcMMEP) were studied in a canine model. Pre-anesthetic baseline tcMMEPs demonstrated consistency in onset latency measurements and variability in measurement of peak-to-peak amplitudes. Changes in tcMMEPs were evaluated following the individual administrations of sodium pentothal, etomidate, halothane, fentanyl, and ketamine. For induction of anesthesia, etomidate was compatible with tcMMEP production, whereas sodium pentothal resulted in loss of hindlimb potentials for a period of 45 minutes. For maintenance of anesthesia, halothane was incompatible with the measurement of tcMMEPs. Fentanyl administration was consistent with the recording of reliable tcMMEPs, with consistent onset latencies but widely variable peak-to-peak amplitudes. Ketamine was compatible with stable and reproducible tcMMEP production. The results of this study suggest that anesthetic agents have a predictable and consistent effect on tcMMEP responses.
authors.affiliation: Department of Orthopaedics, University of Louisville, School of Medicine, Kentucky.
authors.forename: S D
authors.initials: SD
authors.lastname: Glassman
authors.forename: C B
authors.initials: CB
authors.lastname: Shields
authors.forename: R D
authors.initials: RD
authors.lastname: Linden
authors.forename: Y P
authors.initials: YP
authors.lastname: Zhang
authors.forename: A R
authors.initials: AR
authors.lastname: Nixon
authors.forename: J R
authors.initials: JR
authors.lastname: Johnson
mesh_terms: D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D008280:Magnetics; D016343:Monitoring, Intraoperative / Q000379:methods*; D009044:Motor Cortex / Q000187:drug effects / Q000502:physiology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*
chemical_list: D000777:Anesthetics