Intraoperative responses of motor evoked potentials to the novel intravenous anesthetic remimazolam during spine surgery: a report of two cases

Abstract Background Remimazolam is a novel short-acting benzodiazepine characterized by metabolism independent from organ function. We report intraoperative MEP responses of two patients who underwent spine surgery under general anesthesia using remimazolam. Case presentation In case 1, MEP monitoring was successfully performed with the use of a fixed dose of remimazolam at 0.5 mg/kg/h and remifentanil at 0.2 μg/kg/min. In case 2, an increasing dose of remimazolam from 0.5 to 1.5 mg/kg/h during the operation did not affect MEP signals. In both cases, remimazolam was titrated to maintain the values of entropy electroencephalogram (EEG) monitoring at 40–60. Conclusions General anesthesia using remimazolam and remifentanil can be a valuable alternative for spine surgery with MEP monitoring by EEG to assess the optimal dose.