Abstract
BACKGROUND: Unlike the propofol-opioids combination, a single dose of S-ketamine with propofol achieves the same anesthetic effects while effectively minimizing adverse reactions in painless abortion. Ciprofol, a novel analog of propofol, has distinct advantages, its application in painless abortion is underexplored. OBJECTIVES: To investigate a 90% effective dose (ED(90)) of ciprofol and propofol with S-ketamine for painless abortion. DESIGN: This prospective biased coin up-and-down (BCUD) sequential dose-finding study aimed to estimate the ED(90) of ciprofol when administered with 0.15 mg/kg S-ketamine in painless abortion while comparing adverse effects incidence with the ED(90) of propofol when combined with the same dose of S-ketamine. METHODS: Eighty patients were recruited and randomly allocated to either ciprofol or propofol groups, with initial doses of 0.375 mg/kg and 1.5 mg/kg, respectively. The dose for the subsequent patient in the study was based on the response of the preceding patient, following the BCUD design. The study estimated the ED(90) using isotonic regression. Secondary outcomes, including the incidence of injection pain, vital signs, and adverse events, were recorded and compared between the two groups. RESULTS: The ED(90) of ciprofol with 0.15 mg/kg S-ketamine was 0.498 mg/kg (95% confidence interval: 0.498-0.510), while the ED(90) of propofol with 0.15 mg/kg S-ketamine was 1.99 mg/kg (95% confidence interval: 1.98-2.16). Patients in the ciprofol group had a lower incidence of respiratory pause (7.5% vs 52.5%; p < 0.001). Other adverse events and recovery time were comparable between groups. CONCLUSION: Compared to propofol and S-ketamine combination, ciprofol and S-ketamine are equally effective with reduced respiratory depression. Thus, clinicians should consider a dose of 0.5 mg/kg ciprofol with 0.15 mg/kg S-ketamine for painless abortion. TRIAL REGISTRATION: http://www.chictr.org.cn; ChiCTR2400086522; July 5, 2024.