Delirium after cardiac surgery can occur in up to 50% of the patients and has been shown to be significantly associated with increased morbidity and mortality. Advanced age is a significant risk factor of delirium. Numerous studies have shown that sedation with high doses of Dexmedetomidine in the ICU reduces the incidence of postoperative delirium. On the other hand animal studies have shown neuroprotective effects of Dexmedetomidine by means of stimulating alpha2A-adrenoceptors. It is not clear whether the administration of a low dose Dexmedetomidine in cardiac surgery would have any neuroprotective effects by stimulating the alpha 2A-receptors and as such would decrease the incidence of postoperative delirium.