Weilin Yang,1,* Rui Zhou,2,* Xinyu Zhou,1 Xuemeng Chen,1 Dan Zhou,1 Xianjie Zhang1 

1Department of Anesthesiology, Deyang People’s Hospital, Deyang, 618000, People’s Republic of China; 2Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Translational Research Institute of Brain and BrainLike Intelligence, Clinical Research Center for Anesthesiology and Perioperative Medicine, Department of Anesthesiology and Perioperative Medicine, Shanghai Fourth People’s Hospital, School of Medicine, Tongji University, Shanghai, 200434, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Dan Zhou, Department of Anesthesiology, Deyang People’s Hospital, NO. 173, Section 1 of North Taishan Road, Jingyang District, Deyang, Sichuan Province, 618000, People’s Republic of China, Email zd13069617@163.com Xianjie Zhang, Department of Anesthesiology, Deyang People’s Hospital, NO. 173, Section 1 of North Taishan Road, Jingyang District, Deyang, Sichuan Province, 618000, People’s Republic of China, Email zhangxianjie791002@163.com

Objective: To determine the 50% effective dose (ED50) and 95% effective dose (ED95) of oliceridine in suppressing gastroscope insertion responses during painless gastroscopy when combined with 0.3 mg/kg remimazolam.
Methods: This prospective study enrolled 52 patients scheduled for elective painless gastroscopy. The initial dose of oliceridine was 15 ug/kg, with sequential 1.5 ug/kg adjustments based on response. ED50 and ED95 were calculated using the modified Dixon’s up-and-down method and Probit regression analysis. Vital signs, adverse events, anesthesia induction time, recovery time, and satisfaction scores (patients, anesthesiologists, and endoscopists) were recorded.
Results: When combined with 0.3 mg/kg remimazolam, the ED50 and ED95 of oliceridine for suppressing insertion responses were 12.717 ug/kg and 18.818 ug/kg, respectively. The time from drug administration to successful scope insertion was 2 (2, 3) minutes, and the recovery-to-discharge time was 21 (16.5, 22.5) minutes. Vital signs remained stable throughout the procedure, with no hypoxemia, hypotension, or arrhythmias. No anesthesia-related adverse events (eg, nausea, vomiting and dizziness) occurred. Satisfaction scores were high: 10 (10, 10) for patients, 10 (9, 10) for anesthesiologists, and 9 (8, 10) for endoscopists.
Conclusion: Oliceridine combined with 0.3 mg/kg remimazolam effectively suppresses gastroscope insertion response at ED50 and ED95 doses of 12.717 ug/kg and 18.818 ug/kg, respectively. This optimized regimen provides hemodynamic stability, rapid recovery and high procedural satisfaction, with no observed adverse events. These findings support its clinical utility as a safe and efficient anesthetic protocol for painless gastroscopy.
Trial Registration: Chinese Clinical Trial Registry (ChiCTR2400093416).

Keywords: painless gastroscopy, gastroscope insertion response, oliceridine, remimazolam, ED50, ED95, modified Dixon’s sequential method