Postoperative delirium is an acute and fluctuating state of confusion and disorientation, characterized by changes in attention, cognition, consciousness, and perception, with an incidence of 25-70% after cardiac surgery. Possible reasons for this multifactorial complication are hypoperfusion, cerebral microembolization and inflammatory response, which eventually lead to regional or global imbalance between cerebral oxygen demand and supply. This frequent cerebral injury has detrimental and long-lasting consequences and remains a serious healthcare burden, particularly due to its association with higher medical costs, increased morbidity, long-term cognitive deficits, and greater mortality. Progress in reducing the incidence of delirium has been hindered by the lack of a full understanding of its pathophysiology.