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⁻¹ of alfentanil hydrochloride was used for pre-analgesia. The initial single loading dose of remimazolam besylate was 0.12 mg.kg⁻¹, increased or reduced by 0.01 mg.kg⁻¹ 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−1 (95% CI: 0.138-0.160 mg.kg⁻¹) and ED95 0.171 mg.kg⁻¹ (95% CI: 0.159-0.245 mg.kg⁻¹). 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.29 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⁻¹, and the ED95 was 0.171 mg.kg⁻¹.