Determination of ED and ED of remimazolam besylate combined with alfentanil for adult gastroscopy: a prospective dose-finding study.

Background: To explore the median effective dose (ED50) and 95% effective dose (ED95) of remimazolam besylate combined with alfentanil for adult gastroscopy.

Methods: This prospective studyenrolled 31 patients scheduled to painless gastroscopy at Anhui No. 2 Provincial People's Hospital between April and May, 2022. 5 µg.kg of alfentanil hydrochloride was used for pre-analgesia. The initial single loading dose of remimazolam besylate was 0.12 mg.kg, increased or reduced by 0.01 mg.kg for the next patient with modified Dixon sequential method. The modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) was used to assess sedation.

Results: Combined with alfentanil, the ED50 of remimazolam besylate was 0.147 mg.kg (95% CI: 0.138-0.160 mg.kg) and ED95 0.171 mg.kg (95% CI: 0.159-0.245 mg.kg). The induction time after injection of remimazolam besylate was 70 ± 25 s, with the anesthesia recovery time and the observation time in resuscitation room 5.13 ± 2.13 min and 2.32 ± 1.6 min, respectively. Twenty nine patients' vital signs were within acceptable limits during gastroscopy.

Conclusions: The ED50 of remimazolam besylate combined with alfentanil for painless gastroscopy was 0.147 mg.kg, and the ED95 was 0.171 mg.kg.