Abstract: AIM: To investigate the median effective dose of ciprofol combined with sufentanil to inhibit tracheal intubation reaction in patients undergoing intracranial aneurysm embolization. METHODS: Forty-five patients who underwent embolization for intracranial aneurysms were divided into two groups according to age: non-elderly group (aged 18-64 years) and elderly group (aged > 65 years). Patients in the two groups were first given intravenous ciprofol, of which the initial dose of ciprofol was 0.4 mg/kg and sufentanil 0.3 μg/kg and rocuronium 0.6 mg/kg were respectively injected according to BIS value and modified observer's assessment of alertness and sedation (MOAA/S) score. Then, endotracheal intubation was defined as 3 minutes after the induction of the study drug. Dixon sequential method was adopted, and the dose of ciprofol for the next patient was determined according to whether the tracheal intubation reaction was positive (Positive reaction of tracheal intubation was defined as the patient's kinomotor reaction such as coughing during tracheal intubation or the increase of MAP or HR within 2 minutes after intubation was greater than 20% of the basic value). When the tracheal intubation indicated a positive response, the next patient was raised by one gradient, otherwise, it was lowered by one gradient until the study ended at 7 crosses. The common dose ratio of adjacent patients was 1:1.1. The Probit probability method was used to calculate the 50% effective dose (ED₅₀), 95% effective dose (ED₉₅) and the corresponding 95% confidence interval (CI) of ciprofol. Perioperative adverse reactions were recorded in both groups. RESULTS: In the non-elderly group, the ED₅₀ of ciprofol inhibiting positive tracheal intubation reaction was 0.472 mg/kg (95%CI 0.419-0.565 mg/kg), and the ED₉₅ was 0.567 mg/kg (95%CI 0.513-1.293 mg/kg). In the elderly group, the ED₅₀ of ciprofol inhibiting tracheal intubation reaction was 0.409 mg/kg (95%CI 0.383-0.434 mg/kg) and the ED₉₅ was 0.452 mg/kg (95%CI 0.430-0.591 mg/kg). CONCLUSION: The ED₅₀ of ciprofol combined with sufentanil inhibiting positive tracheal intubation reaction was 0.472 mg/kg in non-elderly patients and 0.409 mg/kg in elderly patients.

Key words: ciprofol, intracranial aneurysm, sufentanil, age, intubation reaction