EC50 of Remifentanil for Inhibiting Cardiovascular Responses to Tracheal Intubation in Patients Treated by Different Doses of Oliceridine: A Randomized Controlled Trial Using Up-and-Down Sequential Allocation Methodology

Purpose: The aim was to evaluate its antinociceptive potency by comparing the effect of oliceridine and sufentanil on the half maximal effective concentration (EC 50 ) of remifentanil in suppressing the cardiovascular response to endotracheal intubation under general anesthesia. Patients and methods: A total of 120 patients scheduled for thyroid nodulectomy were randomized into four groups: (i) control group, (ii) sufentanil group, (iii) oliceridine 0.015 mg/kg group, and (iv) oliceridine 0.03 mg/kg group. The initial dosage of remifentanil for induction of general anesthesia was 3 ng/mL. The subsequent infusion dosage of remifentanil was adjusted based on the response to endotracheal intubation in the previous patient in the group, defined as a ≥ 15% change in heart rate (HR) or mean arterial pressure (MAP) before and after intubation. Adjustments were made in increments or decrements of 0.2 ng/mL. The control group received no additional medication, whereas the sufentanil group was administered a 0.15 μg/kg intravenous (IV) bolus of sufentanil. The two oliceridine groups received IV boluses of oliceridine either 0.015 mg/kg or 0.03 mg/kg respectively. Postoperative airway complications, encompassing hoarseness, sore throat, and dysphonia, were also documented. Results: The EC 50 values of remifentanil was 3.728 ng/mL (95% CI: 3.536– 3.943 ng/mL), 2.824 ng/mL (95% CI: 2.620– 3.015 ng/mL), 3.045 ng/mL (95% CI: 2.852– 3.239 ng/mL) and 2.887 ng/mL (95% CI: 2.689– 3.085 ng/mL) in the control, sufentanil, oliceridine 0.015 mg/kg group and oliceridine 0.03 mg/kg group, respectively. Conclusion: The effect of 0.03 mg/kg oliceridine is similar to 0.15 μg/kg sufentanil in reducing the EC 50 of remifentanil in inhibiting the cardiovascular responses induced by trachea intubation. Keywords: oliceridine, EC 50 , hemodynamic response to trachea intubation, the sequential method