ED50 of propofol in combination with low‐dose sufentanil for intravenous anaesthesia in hysteroscopy

OBJECTIVES: Sufentanil has favourable pharmacodynamic and pharmacokinetic properties as an opioid, and it is usually co-administered with propofol as intravenous anaesthesia for hysteroscopic examination or therapeutic surgery. However, the optimal dosage of propofol when it is co-administered with low-dose sufentanil has not yet been established. This study was designed to find the median effective dose of propofol for intravenous anaesthesia when combined with low-dose sufentanil. METHODS: Fifty-four patients were enrolled and randomized into two groups in this prospective study. Sufentanil 0.2 μg/kg (Group A) or 0.1 μg/kg (Group B) was given intravenously before speculum placement. The initial propofol dose was set at 2 mg/kg and varied by 0.1 mg/kg according to the sequential allocation up-and-down rule designed by Dixon and Massey. Respiratory depression, duration of initial dose of propofol, total drug quantity administered and recovery time were recorded. RESULTS: The ED50 of propofol was 1.651 mg/kg (95% CI, 1.561-1.722 mg/kg) in Group A and 1.991 mg/kg (95% CI, 1.902-2.081 mg/kg) in Group B. The ED95 of propofol was 1.827 mg/kg (95% CI, 1.746-2.236 mg/kg) in Group A and 2.153 mg/kg (95% CI, 2.070-2.73 7 mg/kg) in Group B. The initial and total dosage of propofol in Group A were significantly lower than those in Group B, but the incidence of respiratory depression in Group A (26.67%) was significantly higher than that in Group B (4.17%). CONCLUSION: The ED50 values for propofol when co-administered with low-dose sufentanil for intravenous anaesthesia in hysteroscopy were 1.651 mg/kg (sufentanil 0.2 μg/kg) and 1.991 mg/kg (sufentanil 0.1 μg/kg). (www.chictr.org.cn, registration number: ChiCTR1900021224).