# Impact of low-dose sufentanil on the effective sedative dose of ciprofol for BIS-guided induction in elderly patients: an up-and-down sequential allocation trial

## TL;DR

Adding a small dose of sufentanil reduces the needed ciprofol dose for sedation in elderly patients without increasing risks.

## Contribution

This study demonstrates that a low dose of sufentanil significantly reduces the effective dose of ciprofol for BIS-guided anesthesia induction in elderly patients.

## Key findings

- The ED50 of ciprofol was 0.075 mg/kg with sufentanil versus 0.267 mg/kg without.
- Sufentanil reduced ciprofol requirements by 44%−72% without increasing adverse events.
- The regimen is effective and well-tolerated for elderly anesthesia, especially in outpatient settings.

## Abstract

This study aimed to evaluate the effect of a single low dose of sufentanil on the effective dose of ciprofol required to achieve a bispectral index (BIS) <60 during anesthesia induction in elderly patients.

A total of 48 elderly patients were randomly assigned to either the sufentanil plus ciprofol group (S + C group) or the ciprofol alone group (C group). A sufentanil dose of 0.1 μg/kg was administered to the S + C group (diluted to 5 ml), while the C group was administered 5 ml of normal saline. Five minutes later, the initial administration for both groups was 0.3 mg/kg ciprofol. Subsequent doses were adjusted in increments or decrements of 0.05 mg/kg according to the response of the preceding patient within the same treatment group, following two independent, arm-specific up-and-down sequences conducted in parallel. Successful sedation was defined as achieving a BIS score of < 60 within 5 min following ciprofol administration. ciprofol's effective doses (ED50/ED95) were derived through probit regression.

A total of 23 patients were enrolled in the S + C group and 25 in the C group. The estimated ED50 of ciprofol was 0.075 mg/kg (95% CI: 0.024–0.123 mg/kg) in the S + C group and 0.267 mg/kg (95% CI: 0.159–0.361 mg/kg) in the C group. The estimated ED95 values were 0.246 mg/kg (95% CI: 0.141–14.566 mg/kg) and 0.439 mg/kg (95% CI: 0.340–67.768 mg/kg), respectively. The Pearson goodness-of-fit test of group S + C and group C were P = 0.965 and P = 0.615, respectively. The incidence of adverse events, including hypotension (39% vs. 64%) and respiratory depression (17% vs. 16%), did not differ significantly between S + C group and C group.

Under BIS monitoring, the estimated ED50 and ED95 of ciprofol for induction in elderly patients were 0.267 and 0.439 mg/kg, respectively, without sufentanil, and 0.075 and 0.246 mg/kg with 0.1 μg/kg sufentanil. The addition of a low dose of sufentanil reduced the ciprofol requirement for BIS-targeted induction by about 44%−72% without increasing the incidence of hypotension or respiratory depression. This regimen provides an effective and well-tolerated strategy for anesthesia in elderly patients, particularly in day surgery and outpatient settings.

http://www.chictr.org.cn, identifier: ChiCTR2400090926.