Comparison of the ED50 of Ciprofol Combined With or Without Fentanyl for Laryngeal Mask Airway Insertion in Children: A Prospective, Randomized, Open-Label, Dose-Response Trial.

Purpose: This study aimed to estimate the effect of different doses of fentanyl on the median effective dose (ED50) of ciprofol for attenuating the airway and motor response to laryngeal mask airway (LMA) insertion response in healthy children.

Patients and methods: 90 healthy preschool patients undergoing inguinal hernia repair surgery were randomly assigned to one of three groups: C0 (ciprofol+saline), C1 (ciprofol + fentanyl 1µg/kg), C2 (ciprofol + fentanyl 2µg/kg). Anesthesia was induced with either prepared fentanyl or saline, followed by ciprofol. The dose of ciprofol for each patient was determined using the up-and-down sequential study design. The primary outcome was the ED50 of ciprofol required for smooth LMA insertion in the three groups. Additionally, the time to loss of consciousness and any perioperative adverse events were recorded.

Results: Compared with the C0 group, the ED50 (95% confidence interval) of ciprofol in the C1 and C2 groups were significantly lower (1.81 [1.73-1.90]mg/kg versus 0.67 [0.64-0.71]mg/kg and 0.48 [0.42-0.54] mg/kg, respectively; P<0.05). Additionally, the ED50 of ciprofol in the C2 group was lower than that in the C1 group (0.42 [0.42-0.54] mg/kg vs 0.67 [0.64-0.71]mg/kg; P<0.05). Furthermore, the time to loss of consciousness in the C1 and C2 groups decreased by 60% and 53%, respectively, compared to the C0 group. There were no significant differences in the incidence of drug-related hypotension after anesthesia induction among the three groups. No adverse events of hypoxia, bradycardia, or injection pain were observed in any groups.

Conclusion: In healthy, non-obese Chinese children undergoing elective inguinal hernia repair surgery, fentanyl 1 µg/kg and 2 µg/kg before ciprofol injection significantly reduced the ED50 of ciprofol for attenuating LMA response, with minimal occurrence of severe side effects.