Postoperative delirium is a state of confusion characterized by an acute onset and fluctuating course of inattention and either disorganized thinking or an altered level of consciousness.

What are the impacts of postoperative delirium? Approximately 50% of patients undergoing cardiac surgery have postoperative delirium. It is more common in the older surgical population probably owing to their frail preoperative status. The growing body of evidence suggests that the in hospital delirium is associated with poor outcomes including a tenfold increased risk of death, and a fivefold increased risk of nosocomial related complications. Delirium has also been associated with serious longer-term outcomes such as poor functional recovery, and most recently, impaired cognitive function for up to one year after cardiac surgery. 

What can be done? Importantly, intervenable factors, such as peri-operative sedation and analgesia with opioids may contribute to the etiology of delirium. In the setting of cardiac surgery done increasingly in older patients, there is an urgent need to test alternative analgesic techniques that address this issue.