To compare the effectiveness of Dexmedetomidine with Melatonin vs Dexmedetomidine alone in preventing postoperative delirium in elderly patients undergoing cardiac surgery -A prospective randomised interventional study.

Delirium is a brain dysfunction characterized by an acute onset and fluctuating disturbance in consciousness, attention and cognition. Postoperative delirium (POD) is a neuropsychiatric syndrome characterized by disturbances of cognition, attention, consciousness, or perception with  acute onset and fluctuating course.The incidence of POD in older individuals is 15% to 53%, most frequently occurring in the first 3 days after the procedure.Postoperative delirium (POD) is associated with poor outcomes, including prolonged hospital stay, increased costs, and worsened quality of life.Current interventions for delirium prevention primarily involve recognition and improvement of modifiable risk factors besides active treatment of original diseases, but the curative effect is not obvious. Within current guidelines, no pharmacological methods were recommended for delirium prevention. After cardiac surgery, delirium remains the most common neurocognitive complication with an incidence of  6-46% . Patients who have cardiac surgery are at higher risk of postoperative delirium than those following noncardiac surgery because of a higher prevalence of risk factors, such as older age, cerebrovascular disease, diabetes mellitus, and renal disease and receipt of cardiopulmonary bypass.Dexmedetomidine and melatonin have both shown promise in preventing delirium in various patient populations. However, there is a lack of comparative studies evaluating the efficacy of these two agents in cardiac surgery patients. This research proposal outlines a comparative study between dexmedetomidine and melatonin in preventing postoperative delirium in cardiac surgery patients.