Dexmedetomidine to Reduce the Incidence of POCD After Open Cardiac Surgery

Dexmedetomidine (DEX), a highly potent and selective α2-adrenoceptors (α2R) agonist used in clinical practice for sedation, analgesia, and anxiolysis, was recently shown to have beneficial effects on early cognitive changes by reducing delirium in humans.It also reduced memory impairment after surgery and isoflurane anesthesia, both in elderly mice (20-22 months) and in pups exposed to anesthesia in the early postnatal period. Importantly, co-treatment with DEX has been shown to restore learning and memory function in rats exposed to propofol in utero. Therefore, the investigators set out to investigate whether DEX has an effect on cognitive dysfunction months after surgery and whether it accelerates cognitive recovery from anesthesia and surgery. Participants will be randomized 1:1 in permuted blocks of 4 to 8. The randomization sequence will be computer generated and stratified by 2 factors, planned procedure (CABG/CABG + valve or valve only procedure) and study site (for full multicentre trial). In hospital outcomes include delirium (assessed twice daily post-operative day (POD) 0-10, death, hemodynamic instability requiring vasopressors, time to extubation, re-intubation (and reason), length of stay (in Cardiovascular Intensive Care Unit and total hospital), POCD, depressive symptoms between POD 4-10, post-operative complications (infection \[surgical site, sepsis, pneumonia\], myocardial infarction, renal replacement therapy, re-operation, cumulative opioid consumption (to POD 4), in-hospital mortality. Post-operative outcomes include POCD (3/6/12 months), depression (3/6/12 months), mild cognitive impairment (MCI) at 3/6/12 months (defined as 1-2 standard deviations below age matched controls), persistent surgical site pain at sternotomy/thoracotomy/graft harvest site (Brief Pain Inventory, 3/6/12 months), recovery (3,6, 12 months).