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Updated: Aug 18, 2026
Recording Brain Electromagnetic Activity During the Administration of the Gaseous Anesthetic Agents Xenon and Nitrous Oxide in Healthy Volunteers
Published on: January 13, 2018
The effect of nitrous oxide on transcranial magnetic-induced electromyographic responses in the monkey
R F Ghaly1, J L Stone, W J Levy
1Department of Anesthesiology and Critical Care, Cook County Hospital and Hektoen Institute for Medical Research, Chicago, Illinois, USA.
Abstract:
Transcranial magnetic stimulation (TMS) to produce motor evoked potentials (MEPs) is a newly developed intraoperative modality to monitor functional integrity of the motor pathways. The present study was designed to examine the reliability of magnetic MEP recording under nitrous oxide (N2O) inhalation. Following ketamine injection (10 mg/kg i.m.) and endotracheal intubation, 16 monkeys were exposed to N2O:O2 mixture ratios 1:3, 1:1, and 3:1. Electromyographic (EMG) responses, evoked by pulsed magnetic fields applied extracranially to the scalp zone overlying motor cortex, were recorded from the contralateral fore- and hind limb flexor muscles. The scalp topography zone for contralateral muscle excitation was markedly reduced by 75 vol% N2O. Significant stimulation threshold elevation, latency prolongation, and amplitude depression were noted after inhalation of 75 vol% N2O (p <0.05) compared with
