Determination of the 50% and 95% Effective Dose of Remimazolam Combined with Propofol for Intravenous Sedation During Day-Surgery Hysteroscopy

PURPOSE: Remimazolam has demonstrated the potential as a valuable medication for procedural sedation. However, there were some shortcomings for higher doses of remimazolam during hysteroscopy in spite of less frequent adverse events. The aim of this study was to find the 50% and 95% effective dose (ED(50) and ED(95)) of remimazolam when combined with propofol for intravenous sedation during day-surgery hysteroscopy. PATIENTS AND METHODS: Patients were randomly assigned evenly (20 per group) to one of five different dosage of remimazolam: group A (0.05mg/kg), group B (0.075mg/kg), group C (0.1mg/kg), group D (0.125mg/kg) or group E (0.15mg/kg). Intravenous injection of sufentanil 0.1µg/kg was administered before sedative medication. Intravenous anesthesia was commenced with remimazolam. Subsequently, propofol was administered at 1mg/kg and maintained at 6mg/kg/h. Success was defined when the patient did not move during cervical dilation, had sufficient sedation as judged by SE <60 and no requirement for rescue doses. The success rate, induce and average dosage of propofol, the induction time, total surgery time, recovery time, and adverse events were recorded. Estimate of ED(50) and ED(95) with 95% confidence interval (CI) was performed by probit regression. RESULTS: The mean (95% CI) values for ED(50) and ED(95) of remimazolam in patients were 0.09 (0.08−0.11) mg/kg and 0.21 (0.16–0.35) mg/kg, respectively. There was no difference in the induction time, total surgery time, and recovery time among groups. No serious adverse events occurred in all patients. CONCLUSION: The dose–response effects of remimazolam were evaluated for intravenous sedation during hysteroscopy. A combination of remimazolam and propofol was recommended to produce stabler sedation, reduce the total dosage and have less effect on cardiovascular and respiratory depression.