• Satoki Inoue, Masahiko Kawaguchi, Masahiro Takahashi, Meiko Kakimoto, Takanori Sakamoto, Katsuyasu Kitaguchi, Hitoshi Furuya, Tetsuya Morimoto, and Toshisuke Sakaki.
• Department of Anesthesiology and Neurosurgery, Nara Medical University, Japan. sinoue@vapop.ucsd.edu
• Can J Anaesth. 2003 Jan 1;50(1):86-91.

PurposeTo investigate whether motor evoked potentials (MEP) to transcranial electrical stimulation under constant blood propofol concentration are affected by the arousing effect of surgical noxious stimuli.MethodsTwenty patients who underwent elective spinal surgery were studied. Patients were anesthetized with 50% nitrous oxide in oxygen, fentanyl, and propofol to maintain the bispectral index (BIS) score around 50. MEP in response to a multipulse transcranial electrical stimulation at stimulus sites of C3-C4 were recorded over the right abductor pollicis brevis muscle. Changes of peak-to-peak amplitude and onset latency of MEP, BIS score before and after surgical stimuli were evaluated. Propofol plasma concentration was measured at the same time points.ResultsBoth MEP amplitude and latency did not change significantly after surgical stimuli although BIS increased significantly (48 +/- 6 to 58 +/- 5; P < 0.05). Plasma propofol concentration was maintained at the same level between the two measurement points (3.3 +/- 0.7 to 3.3 +/- 0.7 micro g*mL(-1)). There was no relation between BIS change and changes of MEP amplitude and latency, and propofol plasma concentration.ConclusionMEP to the transcranial electrical stimulation under a constant and clinically appropriate blood propofol concentration are not affected by surgical noxious stimuli.

26 keywords...

hide…