Objective To observe 50% effective dose (ED₅₀) of ciprofol combined with dezocine in inhibiting body reaction in patients undergoing gynecological day surgery by modified sequential method.

Methods A total of 25 patients who underwent gynecological day surgery in the Affiliated Hospital of Yangzhou University in April 2023 were selected as the study objects. Patients were aged 18 to 58 years with body mass index (BMI) ranging from 19 to 27 kg/m² and American Society of Anesthesiologists (ASA) classification ranging from Ⅰ to Ⅱ. Dezocine 5 mg was injected intravenously and ciprofol was injected intravenously, the initial dose was 0.3 mg/kg, and surgery was performed after the patient's eyelash reflex disappeared. Ciprofol should be added 0.02 mg/kg in case of body reaction. According to Dixon's modified sequential method, the dose of ciprofol for the next patient was determined by the response of the previous patient, and the adjacent interval dose was 0.05 mg/kg. The ED₅₀, 95% effective dose (ED₉₅) and 95%CI were calculated by Probit regression analysis.

Results Ciprofol combined with dezocine, the ED₅₀ of ciprofol for gynecological day surgery was 0.312 (0.260 to 0.375) mg/kg, and the ED₉₅ was 0.410 (0.358 to 0.887) mg/kg.

Conclusion The ED₅₀ of ciprofol combined with dezocine is 0.312 mg/kg.