Seated Sedation-Analgesia With Preserved Spontaneous Ventilation to Facilitate Intubation After Transition to the Supine Position: A Case Report

Induction of general anesthesia in the sitting position may be associated with hemodynamic instability resulting from decreased venous return, as well as challenges in airway management due to limited access to the airway. However, in patients who cannot tolerate the supine position because of post-traumatic pain or other conditions, induction in the sitting position may be unavoidable. In this report, we describe a case in which sedation was initiated in the sitting position, spontaneous respiration was preserved during the transition to the supine position, and tracheal intubation was subsequently performed, resulting in safe anesthetic management. The patient was a woman in her 40s with obesity who was scheduled to undergo robot-assisted surgery for a uterine malignancy associated with atypical endometrial hyperplasia. She had a history of a lumbar vertebral compression fracture secondary to a road traffic accident and was unable to tolerate the supine position while awake. After arrival in the operating room, remimazolam infusion was initiated at 6 mg·kg⁻¹·hour⁻¹ under supplemental oxygen. The patient was then moved to the supine position while maintaining spontaneous respiration. Following the administration of rocuronium and remifentanil, tracheal intubation was performed using a video laryngoscope. No complications, including decreased peripheral oxygen saturation, were observed during induction. The patient's postoperative course was uneventful without hypoxemia after extubation, and she was discharged on postoperative day 4. In patients with obesity who cannot tolerate the supine position due to severe pain, an induction strategy using remimazolam that preserves spontaneous respiration in the semi-sitting position while transitioning to the supine position may be a useful option. When performing induction in the sitting position, developing an anesthetic plan centered on agents with available antagonists may further enhance patient safety.