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The intraoperative motor-evoked potential when propofol was changed to remimazolam during general anesthesia: a case
Shoto Yamada1, Yukinori Akiyama2, Shunsuke Tachibana1
1Department of Neurosurgery, Sapporo Medical University, South 1, West 16, Chuo-ku, Sapporo-shi, Hokkaido, 060-8543, Japan.
Abstract:
Remimazolam is a short-acting benzodiazepine that was approved for clinical use in 2020. We report three patients who underwent surgery for cerebral and spinal cord tumors, in whom transcranial electrical stimulation-motor-evoked potential (TES-MEP) was successfully monitored under general anesthesia with remimazolam. During total intravenous anesthesia with propofol at a target concentration of 2.7 - 3.5 µg/mL and 0.1 - 0.35 µg/kg/min of remifentanil, delayed awakening, bradycardia, and hypotension during propofol anesthesia were expected in all three cases. With patient safety as the top priority, we considered changing the anesthetic agent. Propofol was replaced with remimazolam at a loading dose of 12 mg/kg/h for a few seconds (case 3), followed by 1 mg/kg/h for maintenance (cases 1-3). TES-MEP was recorded during propofol and remimazolam administration in all three patients. Amplitudes of TES-MEP during anesthesia with propofol and remimazolam were 461.5 ± 150 µV and 590.5 ± 100.9 µV, 1542 ± 127 µV and 1698 ± 211 µV, and 581.5 ± 91.3 µV and 634 ± 82.7 µV sequentially from Case 1. Our findings suggest that intraoperative TES-MEP could be measured when anesthesia was managed with remimazolam at 1 mg/kg/h.
Insights
Remimazolam, a short-acting anesthetic, allowed successful monitoring of transcranial electrical stimulation-motor-evoked potentials (TES-MEP) during brain and spinal cord tumor surgeries. This anesthetic agent offers a viable alternative for maintaining TES-MEP monitoring.
Area of Science:
- Anesthesiology
- Neurosurgery
- Neurophysiology
Background:
- Remimazolam is a recently approved short-acting benzodiazepine anesthetic.
- Monitoring transcranial electrical stimulation-motor-evoked potentials (TES-MEP) is crucial during neurosurgery.
- Propofol anesthesia can be associated with delayed awakening, bradycardia, and hypotension, potentially impacting TES-MEP monitoring.
Purpose of the Study:
- To evaluate the feasibility of intraoperative TES-MEP monitoring under general anesthesia with remimazolam.
- To assess the impact of remimazolam on TES-MEP amplitudes compared to propofol.
Main Methods:
- Case series of three patients undergoing surgery for cerebral and spinal cord tumors.
- General anesthesia was initially induced with propofol and remifentanil, then transitioned to remimazolam.
- TES-MEP was recorded during both propofol and remimazolam administration phases.
Main Results:
- Successful TES-MEP monitoring was achieved throughout anesthesia with remimazolam.
- TES-MEP amplitudes showed comparable or slightly increased values under remimazolam compared to propofol.
- Remimazolam was administered at a maintenance dose of 1 mg/kg/h.
Conclusions:
- Remimazolam can be safely used for general anesthesia in patients undergoing neurosurgery requiring TES-MEP monitoring.
- Intraoperative TES-MEP monitoring is feasible with remimazolam-based anesthesia.
- Remimazolam presents a potential alternative anesthetic agent for neurosurgical procedures.
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