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Effect of Remimazolam on Transcranial Electrical Motor-evoked Potential in Spine Surgery: A Prospective, Preliminary,
Shuichiro Kurita1, Kenta Furutani1, Yusuke Mitsuma1
1Department of Anesthesiology, Niigata University Medical and Dental Hospital, Niigata.
Background:
Some anesthetic drugs reduce the amplitude of transcranial electrical motor-evoked potentials (MEPs). Remimazolam, a new benzodiazepine, has been suggested to have little effect on MEP amplitude. This prospective, preliminary, dose-escalation study aimed to assess whether remimazolam is associated with lower MEP amplitude in a dose-dependent manner.
Methods:
Ten adult patients scheduled for posterior spinal fusion were included in this study. General anesthesia was induced with a continuous infusion of remifentanil and remimazolam. After the patient lost consciousness, the infusion rate of remimazolam was set to 1 mg/kg/h, and the patient underwent tracheal intubation. Baseline MEPs were recorded under 1 mg/kg/h of remimazolam in a prone position. Thereafter, the infusion rate of remimazolam was increased to 2 mg/kg/h, with a bolus of 0.1 mg/kg. Ten minutes after the increment, the evoked potentials were then recorded again. The primary endpoint was the MEP amplitude recorded in the left gastrocnemius muscle at 2 time points.
Results:
There was no difference in MEP amplitude recorded from the left gastrocnemius muscle before and after increasing remimazolam (median [interquartile range]: 0.93 [0.65 to 1.25] mV and 0.70 [0.43 to 1.26] mV, respectively; P =0.08). The average time from the cessation of remimazolam administration to neurological examination after surgery was 4 minutes using flumazenil.
Conclusions:
This preliminary study suggests that increasing remimazolam from 1 to 2 mg/kg/h might have an insignificant effect on transcranial electric MEPs.
Insights
Remimazolam, a new anesthetic, showed no significant dose-dependent effect on motor-evoked potential (MEP) amplitude during spinal fusion surgery. This suggests remimazolam may preserve MEPs, crucial for monitoring nerve function.
Area of Science:
- Anesthesiology
- Neurophysiology
- Spinal Surgery
Background:
- Anesthetic drugs can reduce motor-evoked potential (MEP) amplitude.
- Remimazolam, a novel benzodiazepine, is hypothesized to have minimal impact on MEPs.
Purpose of the Study:
- To investigate the dose-dependent effect of remimazolam on MEP amplitude.
- To assess remimazolam's impact on neurophysiological monitoring during anesthesia.
Main Methods:
- Prospective, preliminary, dose-escalation study.
- Ten adult patients undergoing posterior spinal fusion.
- MEP amplitudes recorded at remimazolam infusion rates of 1 mg/kg/h and 2 mg/kg/h.
Main Results:
- No significant difference in MEP amplitude was observed after increasing remimazolam dosage (P = 0.08).
- The median MEP amplitude was 0.93 mV at 1 mg/kg/h and 0.70 mV at 2 mg/kg/h.
- Neurological examination occurred a median of 4 minutes post-surgery with flumazenil reversal.
Conclusions:
- Increasing remimazolam from 1 to 2 mg/kg/h appears to have an insignificant effect on transcranial MEPs.
- Remimazolam may be a suitable anesthetic option for procedures requiring MEP monitoring.
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