A syndrome  of acute brain dysfunction, delirium causes observable changes in behavior. A hallmark of delirium is a disturbance of consciousness and cognition, with inattention that develops acutely and fluctuates over time. (See Understanding diagnostic criteria for delirium.) In critically ill adults, delirium can lead to more ventilator days, more intensive care unit (ICU) days, longer hospital stays, longterm cognitive problems, and an increased mortality risk. Adults have described…