Remimazolam
Remimazolam, sold under the brand name Byfavo, is a medication for the induction and maintenance of procedural sedation in adults for invasive diagnostic or surgical procedures lasting 30 minutes or less. It is a benzodiazepine drug, developed by PAION AG in collaboration with several regional licensees as an alternative to the short-acting imidazobenzodiazepine midazolam, for use in the induction of anesthesia and conscious sedation for minor invasive procedures. Remimazolam was found to have both a more rapid onset and a shorter duration than midazolam, and human clinical trials showed a faster recovery time and predictable, consistent pharmacokinetics, suggesting some advantages over existing drugs for these applications.
A study aims to explore the effect of sleep deprivation by modified multiple platform-water maze (MMP-WM) on rat neurological function and Tau protein in the hippocampus, as well as the intervention effect of remimazolam. First, 40 Sprague Dawley (SD) rats were divided into a control group (no treatment), a Rem group (remimazolam), an MMP-WM group (sleep deprivation model in rats established by MMP-WM), and a combined group (MMP-WM + remimazolam). Five rats were randomly selected from each group for behavior tests at 1 d and 7 d of drug administration or sleep deprivation for Morris water maze and open field test. After that, the rats were executed, the hippocampus was isolated for Nissl staining, and the protein expression of phosphorylated Tau (p-Tau) in the CA1 region of the hippocampus was measured by immunohistochemistry. At 1 d, the status in the MMP-WM group was more similar to that in the control group The MMP-WM group showed sparsely arranged hippocampal CA1 neurons, reduced number of Nissl bodies, prolonged escape latency, decreased number of platform crossings and percentage of activity time in the central region, substantially increased p-Tau expression. In contrast, the combined group showed significant improvement in nerve injury, behavior test results, and p-Tau at 7 d compared with the MMP-WM group and the same group at 1 d. In addition, detection of brain-derived neurotrophic factor (BDNF) and neurotransmitter levels in the cerebrospinal fluid also showed improved neurologic function in the combined group. These results confirm that MMP-WM was effective in the establishment of sleep sleep-deprivation rat model that accurately reflects the pathological manifestations of sleep disorders in humans, and the use of remimazolam effectively reversed the pathological damage in sleep-deprived rats. 1).
A 12-year-old girl required general anesthesia under intraoperative direct cortical motor evoked potentials monitoring due to supratentorial glioma. Remimazolam-based anesthesia was selected, instead of propofol, due to the patient's egg hypersensitivity. Stable myogenic MEPs were recorded throughout the surgery with remimazolam at 0.9 mg/kg/h and remifentanil at 0.35 μg/kg/min, following adjustments of stimulation intensity and titration of remimazolam infusion. Neither intraoperative memory nor motor deficits were present after surgery.
Kamata et al. presented a pediatric case whose dc-MEP was recorded under remimazolam anesthesia. The cardiovascular stability and avoidance of propofol infusion syndrome with remimazolam were superior to propofol 2).
In a retrospective study, patients who underwent awake craniotomy (n = 36) between December 2019 and January 2021 were divided into two groups: the propofol group (P group: n = 21) and the remimazolam group (R group: n = 15). There was no significant difference in the recovery time between the two groups (p = 0.18). The number of patients experiencing nausea was higher in the R group than in the P group (p = 0.02); however, regression analysis revealed that the use of remimazolam contributed to increased intraoperative nausea (odds ratio = 14.4, p = 0.04). No significant differences were observed in the frequency of vomiting and other intraoperative complications between the two groups. In conclusion, remimazolam has the potential for use as an alternative drug in anesthetic management during awake craniotomy 3).
Comparison of sensory evoked potentials during neurosurgery under remimazolam anesthesia with those under propofol anesthesia 4)