Intrathecal Dexmedetomidine and Postoperative Delirium in Elderly Hip Fracture Surgery

Postoperative delirium (POD) is a common and serious complication in elderly patients undergoing surgical repair for hip fractures, often triggered by acute pain, surgical stress, neuroinflammation, and opioid consumption. Although spinal anesthesia using bupivacaine is commonly performed, local anesthetics alone often require additional systemic rescue opioids for postoperative pain relief, which can further increase delirium risk. Dexmedetomidine is a selective alpha-2 adrenergic agonist that has demonstrated neuroprotective, anti-inflammatory, and opioid-sparing effects. The purpose of this clinical trial is to evaluate whether adding intrathecal dexmedetomidine as an adjuvant to hyperbaric bupivacaine during spinal anesthesia reduces the incidence and severity of postoperative delirium compared to hyperbaric bupivacaine alone in geriatric patients undergoing hip fracture surgeries. Participants will be randomly assigned to one of two groups: * Dexmedetomidine Group: Receives hyperbaric bupivacaine 0.5% (10 mg) combined with 5 µg dexmedetomidine intrathecally. * Control Group: Receives hyperbaric bupivacaine 0.5% (10 mg) combined with normal saline intrathecally. The primary outcome is the incidence of postoperative delirium evaluated using the Confusion Assessment Method (CAM) twice daily during the first 48 hours following surgery. Secondary assessments include the duration and severity of delirium episodes, spinal block characteristics, hemodynamic stability, postoperative pain scores, rescue analgesic consumption, sedation levels, adverse events, and total hospital length of stay.