Respiratory safety of remimazolam-alfentanil sedation in non-intubated thoracoscopic surgery: study protocol for a randomized controlled trial

Background Non-intubated thoracic surgery (NITS), an emerging technique in modern thoracic anesthesia, allows patients to maintain spontaneous ventilation without tracheal intubation or mechanical lung isolation. This approach offers physiological advantages, including reduced ventilator-induced lung injury and enhanced postoperative recovery. Typically performed under regional anesthesia combined with moderate sedation, NITS has gained increasing adoption due to advancements in anesthetic techniques and the introduction of novel sedative agents. Among modern anesthetic regimens, remimazolam-a short-acting benzodiazepine-combined with alfentanil, a rapid-onset opioid, has demonstrated favorable pharmacokinetic properties, including minimal respiratory and circulatory depression. This combination has been successfully employed in procedures requiring spontaneous breathing, such as gastrointestinal endoscopy and bronchoscopy. However, its safety and efficacy in non-intubated thoracoscopic lung surgery remain underexplored. This study aims to evaluate the perioperative safety profile and clinical efficacy of remimazolam-alfentanil anesthesia in patients undergoing NITS, with a focus on respiratory stability, hemodynamic control, and postoperative recovery outcomes. Methods This is a single-blind, randomized controlled trial. Patients scheduled for elective non-intubated thoracoscopic lung surgery will be selected and randomly assigned to the propofol-alfentanil or remimazolam-alfentanil group. The trial will take place at the First Affiliated Hospital of Shandong First Medical University in Jinan City, Shandong Province, China, among 390 adult patients.The primary outcome is the incidence of hypoxemia, which is defined as SpO ₂ (oxygen saturation measured using pulse oximetry)< 90% for > 10 s. Discussion This study aims to observe the safety and efficacy of remimazolam combined with alfentanil in non-intubated thoracoscopic surgery. Remimazolam combined with alfentanil has been widely used in surgeries with spontaneous breathing and has shown the advantage of less respiratory and circulatory depression. We hypothesize that it may have certain advantage in non-intubated thoracoscopic surgery with spontaneous ventilation. We hope that our research can provide a better sedative drug option for non-intubated thoracoscopic lung surgery. Trial Registration: This study was registered on clinicaltrials.gov (NCT06810843) on February 1, 2025.