Effect of Dexmedetomidine Dosage on Postoperative Delirium in Geriatric Orthopedic Surgery

Patients receive a specific low-dose intravenous infusion of Dexmedetomidine during major lower limb orthopedic surgery under opioid-based general anesthesia. The intervention aims to evaluate the dose-response relationship regarding its neuroprotective effects on postoperative delirium (POD).

Patients receive a higher-dose intravenous infusion of Dexmedetomidine during the surgical procedure. This arm is designed to determine if higher concentrations of DEX provide a more significant reduction in the incidence and severity of postoperative delirium and cognitive dysfunction compared to the lower dose.

Patients in this group receive standard opioid-based general anesthesia using fentanyl without the addition of Dexmedetomidine. This group serves as the baseline to compare the efficacy of DEX in preventing cognitive decline.