To investigate the median effective dose (ED₅₀) of ciprofol combined with alfentanil inhibiting responses to gastroscopy in geriatric patients.

A total of 115 elderly patients scheduled for elective painless gastroscopy were enrolled in this study. Patients scheduled for gastroscopy were divided into four groups according to age and gender: Group A consisted of males aged 65-74 years, Group B consisted of females aged 65-74 years, Group C consisted of males aged 75-85 years, and Group D consisted of females aged 75-85 years. Based on the modified Dixon sequential test method, intravenous alfentanil 4 ug·kg^-1 was administered followed by ciprofol, with an initial dose of 0.3 mg·kg^-1 and the injection time was longer than 30 s, and the dose gradient was set at 0.03 mg·kg^-1. The ED₅₀, 95% effective dose (ED₉₅), and their 95% confidence intervals (CIs) for gastroscopic response in the four patient groups were calculated using probit regression analysis. Additionally, vital signs were documented for all groups.

The calculated ED₅₀ and its 95% CI for the dosage of ciprofol in the four groups of elderly patients were 0.19 (0.17-0.21) mg·kg^-1 in group A, 0.20 (0.18-0.22) mg·kg^-1 in group B, 0.15 (0.12-0.18) mg·kg^-1 in group C, 0.17(0.15-0.19) mg·kg^-1 in group D. The ED₉₅ and its 95% CI were 0.23 (0.09-0.32) mg·kg^-1 for Group A, 0.25 (0.23-0.30) mg·kg^-1 for Group B, 0.20 (0.18-0.38) mg·kg^-1 for Group C, and 0.21 (0.19-0.31) mg·kg^-1 for Group D. There was no statistically significant difference in the ED₅₀ of ciprofol between genders within the same age group (P>0.05). However, the ED₅₀ of ciprofol in patients aged 75-85 was significantly lower than that in patients aged 65-74 of the same gender (P<0.05). The Hosmer-Lemeshow test indicated that the Probit models for all four groups fitted well (P>0.05).

The ED₅₀ and its 95% CI for the inhibition of the entry response during painless gastroscopy in elderly patients by ciprofol combined with 4.00 ug·kg^-1 alfentanil were 0.19 (0.17-0.21) mg·kg^-1 in group A, 0.20 (0.18-0.22) mg·kg^-1 in group B, 0.15 (0.12-0.18) mg·kg^-1 in group C, 0.17(0.15-0.19) mg·kg^-1 in group D. Age-stratified dosage adjustment of ciprofol is necessary to minimize adverse reactions.