Effects of remimazolam and propofol on sleep rhythm and delirium after spinal surgery in elderly patients.

Objective: This study aims to investigate the effects of remimazolam on postoperative melatonin secretion, sleep rhythm, and postoperative delirium (POD) in elderly patients undergoing spinal surgery.

Methods: We selected 120 elderly patients scheduled for elective spinal surgery (lumbar interbody fusion via a posterior approach) under general anaesthesia from November 2023 to January 2024. They were divided into 2 groups according to medication, the remimazolam group (R group) and the propofol group (P group), with 60 patients in each group. The R group received an induction dose of remimazolam 0.2 ~ 0.3 mg/kg, followed by a continuous infusion of remimazolam at 0.1-0.2 mg/kg/h for maintenance. The P group received an induction dose of propofol 1.5 ~ 2.0 mg/kg, followed by a continuous infusion of propofol at 4-6 mg/kg/h for maintenance. Melatonin and cortisol concentrations were measured at 04:00 on the day of surgery and postoperative days 1, 2, and 3. The Pittsburgh Sleep Quality Index (PSQI) and resting visual analog scale (VAS) pain scores were recorded on the day before surgery, and on postoperative days 1 and 2, as well as prior to discharge. Additionally, we documented extubation time, PACU stay duration, total and effective button presses on the analgesia pump, instances of supplemental analgesia, and occurrence of complications.

Results: Compared to the P group, the R group exhibited significantly shorter extubation time and PACU stay duration (P < 0.05). On postoperative days 1 and 2 at 04:00, melatonin concentrations were significantly higher, cortisol concentrations were significantly lower, and PSQI scores were significantly reduced in the R group (P < 0.05). The incidence of POD and postoperative sleep disturbance (POSD) was also significantly lower in the R group (P < 0.05). Furthermore, on postoperative day 1, the PSQI and resting VAS pain scores in the R group were significantly lower compared to the P group (P < 0.05). There were no statistically significant differences between the two groups in terms of surgery duration, anaesthesia duration, total and effective analgesia pump button presses, supplemental analgesia rates, intraoperative hypotension, or incidences of postoperative nausea, vomiting, dizziness, and respiratory depression (P > 0.05).

Conclusion: The use of remimazolam in elderly patients undergoing spinal surgery has a minimal impact on postoperative melatonin and cortisol secretion rhythms and sleep patterns, and may reduce the incidence of POD and alleviate postoperative sleep disturbances.