Comparison of Remimazolam versus Dexmedetomidine on Hemodynamics in Older Patients Under Lower Extremity Orthopedic Surgery with Spinal Anesthesia: A Randomized Controlled Trial.

Purpose: To compare the effects of remimazolam and dexmedetomidine on the hemodynamics in elderly patients undergoing orthopedic surgery under spinal anesthesia. Methods: This study evaluated 126 patients aged ≥ 60 years undergoing lower-extremity orthopedic surgery under spinal anesthesia, randomizing them into remimazolam and dexmedetomidine groups. The primary outcome was the incidence of hemodynamic fluctuations, such as hypotension and bradycardia. The secondary endpoints included the cumulative dose vasoactive medication and the incidence of hypertension, tachycardia, postoperative nausea and vomiting (PONV), postoperative delirium (POD), and hypoxemia. Continuous hemodynamic variables including mean arterial pressure (MAP) and heart rate (HR) were recorded at baseline, every 5 min for the first 20 min after intravenous infusion of sedatives, every 10 min thereafter, up to one hour, at the end of the surgery, and in the post-anesthesia care unit (PACU). Results: Compared to dexmedetomidine group, patients in the remimazolam group demonstrated significantly higher MAP at three specific time points (60 minutes after baseline, at the end of surgery, and in the PACU) and higher HR at all time points after T3 (15 minutes after baseline). The remimazolam group also reduced norepinephrine and atropine interventions. There were no statistically significant differences in other adverse events between the two groups. Conclusion: Remimazolam demonstrated superior hemodynamic stability and fewer adverse cardiovascular events than dexmedetomidine, along with reduced requirements for vasoactive medications, making it an alternative to intraoperative sedation in older patients undergoing lower limb surgery under spinal anesthesia.