The Median Effective Dose of Ciprofol Combined with Sufentanil for Inhibiting Responses to Gastroscope Insertion in Obese Patients: A Prospective, Single-Center Study.

Background: Ciprofol, a recently developed intravenous anesthetic, whereas sufentanil is a widely used adjuvant for gastroenteroscopy sedation. The recommended dosage of ciprofol for obese patients remains unclear. Our study aimed to determine the median effective dose (ED₅₀) of ciprofol in combination with sufentanil for obese patients undergoing gastroscopy sedation.

Methods: A total of 70 patients undergoing painless gastroscopy from July 2024 to September 2024 were recruited. Patients were assigned to the obese group (body mass index [BMI]≥28 kg/m², n=34) and non-obese group (18.5 kg/m² ≤BMI<24 kg/m², n=36). All patients received 0.1 μg/kg of sufentanil, and the ciprofol dose was determined by the modified Dixon sequential method with an initial dose of 0.4 mg/kg and a dose gradient of 0.01 mg/kg. The dose of ciprofol administered to the subsequent patient was determined by the response of the preceding patient. The response referred to the patient's cough, swallowing, and body movement during gastroscope insertion. The primary outcome was the ED₅₀ of ciprofol in each group, while the secondary outcomes comprised the incidences of hypoxemia, hypotension, bradycardia, postoperative nausea and vomiting (PONV), and hemodynamic parameters.

Results: The ED₅₀ of ciprofol was 0.278 mg/kg (95% confidence interval [CI]: 0.226-0.297 mg/kg) in the obese group and 0.347 mg/kg (95% CI: 0.329-0.360 mg/kg) in the non-obese group for gastroscopy sedation. The ED₅₀ of ciprofol in the obese group was significantly lower than that in the non-obese group (P<0.05). The incidence of hypoxemia in the obese group was significantly higher than that in the non-obese group (P<0.05).

Conclusion: Obesity affected the ED₅₀ of ciprofol, suggesting that the ciprofol dosage should be adjusted in obese patients.