Motor and somatosensory evoked potentials are well maintained in patients given dexmedetomidine during spine surgery.
BACKGROUND
Many commonly used anesthetic agents produce a dose-dependent amplitude reduction and latency prolongation of evoked responses, which may impair diagnosis of intraoperative spinal cord injury. Dexmedetomidine is increasingly used as an adjunct for general anesthesia. Therefore, the authors tested the hypothesis that dexmedetomidine does not have a clinically important effect on somatosensory and transcranial motor evoked responses.


METHODS
Thirty-seven patients were enrolled and underwent spinal surgery with instrumentation during desflurane and remifentanil anesthesia with dexmedetomidine as an anesthetic adjunct. Upper- and lower-extremity transcranial motor evoked potentials and somatosensory evoked potentials were recorded during four defined periods: baseline without dexmedetomidine; two periods with dexmedetomidine (0.3 and 0.6 ng/ml), in a randomly determined order; and a final period 1 h after drug discontinuation. The primary outcomes were amplitude and latency of P37/N20, and amplitude, area under the curve, and voltage threshold for transcranial motor evoked potential stimulation.


RESULTS
Of the total, data from 30 patients were evaluated. Use of dexmedetomidine, as an anesthetic adjunct, did not have an effect on the latency or amplitude of sensory evoked potentials greater than was prespecified as clinically relevant, and though the authors were unable to claim equivalence on the amplitude of transcranial motor evoked responses due to variability, recordings were made throughout the study in all patients.


CONCLUSIONS
Use of dexmedetomidine as an anesthetic adjunct at target plasma concentrations up to 0.6 ng/ml does not change somatosensory or motor evoked potential responses during complex spine surgery by any clinically significant amount.
Bala
Endrit
E
Department of Outcomes Research, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio 44195, USA.
Sessler
Daniel I
DI
Nair
Dileep R
DR
McLain
Robert
R
Dalton
Jarrod E
JE
Farag
Ehab
E
D000293:Adolescent; D000328:Adult; D000368:Aged; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D019540:Area Under Curve; D018592:Cross-Over Studies; D000077335:Desflurane; D020927:Dexmedetomidine / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D019054:Evoked Potentials, Motor / Q000187:drug effects*; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects*; D005260:Female; D006801:Humans; D007530:Isoflurane / Q000008:administration & dosage / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D010880:Piperidines / Q000008:administration & dosage; D011930:Reaction Time / Q000187:drug effects; D000077208:Remifentanil; D016037:Single-Blind Method; D013131:Spine / Q000601:surgery*
D018712:Analgesics, Non-Narcotic; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D010880:Piperidines; D020927:Dexmedetomidine; D000077335:Desflurane; D007530:Isoflurane; D000077208:Remifentanil