Determining ED50 of Nalbuphine for Intraoperative Analgesia in Elderly Patients Undergoing Percutaneous Kyphoplasty: A Prospective, Double-Blind, Single-Center, Dose-Finding Study.

Background: Nalbuphine is a novel intravenous anesthetic. Studies have shown that it features a rapid onset of action, a fast recovery time, slight inhibition of respiratory and cardiovascular functions, and a low incidence of adverse reactions. This study aims to determine the median effective dose (ED50) of nalbuphine for intraoperative analgesia in elderly patients undergoing percutaneous kyphoplasty (PKP) and to evaluate its safety profile, thereby providing a reference for its rational clinical use. Methods: We included 22 patients aged 60-85 years of either sex who underwent PKP with an American Society of Anesthesiologists (ASA)grade I to II. In this study, the dose-finding strategy of nalbuphine followed a modified Dixon's up-and-down method with an initial dose of 0.1 mg/kg and an increment of 0.01 mg/kg. Dixon up-and-down sequential methodology was utilized to ascertain the ED50 of nalbuphine. NRS pain score≤3 was considered as effective for analgesia, otherwise it was considered as ineffective for analgesia. Circulatory parameters and adverse effects were recorded. Results: The analgesia was effective in 13 patients and ineffective in 9 patients according the NRS Pain score during operating. ED50 of single-dose intravenous nalbuphine injection in inhibiting intraoperative analgesia in elderly patients undergoing PKP was (0.062 mg/kg, 95% CI: 0.041-0.081 mg/kg). Conclusion: The ED50 (0.062 mg/kg, 95% CI: 0.041-0.081 mg/kg) for intraoperative analgesia with single-dose intravenous nalbuphine were established in elderly patients undergoing PKP. Nalbuphine exhibited a lower incidence of anesthesia-related adverse events. Trial Registration: ChiCTR2300071476.