Cognitive Outcomes After Dexmedetomidine Sedation in Cardiac Surgery Patients

This study is evaluating whether dexmedetomidine — a sedation drug that also has protective effects on the brain — can reduce cognitive decline (post-operative cognitive dysfunction, or POCD) in older adults who undergo open-heart surgery such as coronary artery bypass grafting (CABG) or valve replacement. Cognitive decline after cardiac surgery is common in older patients and can significantly impact quality of life. Dexmedetomidine may protect the brain during recovery in the ICU. You may be eligible if: - You are 60 years or older - You are scheduled for CABG (with or without valve repair/replacement) or valve replacement surgery via sternotomy or thoracotomy - Your recovery will begin in the Cardiovascular Intensive Care Unit (CVICU) You may NOT be eligible if: - You have not provided consent - You have significant pre-existing cognitive problems (CogState Brief Battery score below 80) - You are having aortic arch replacement or surgery requiring hypothermic circulatory arrest (such as a Bentall procedure) - You have an allergy or contraindication to dexmedetomidine (such as untreated heart block, cirrhosis, heart rate below 50, severe heart failure, or renal failure on dialysis) - You are unlikely to be able to complete follow-up cognitive assessments at 3, 6, and 12 months Talk to your cardiac surgeon or anesthesiologist about this study if you are an older adult planning to undergo heart surgery and are concerned about memory or cognitive changes afterward.