Delirium and cognitive dysfunction in the intensive care unit

Delirium remains an underrecognized, but highly prevalent, form of organ dysfunction in the intensive care unit (ICU). Intensivists have begun to benefit from elucidation of risk factors for delirium in the ICU, some of which are modifiable, whereas others are not. In the last 5 years, a new tool for use in detecting delirium among critically ill patients has been adapted, validated, and found objectively reliable for use at the bedside by nonpsychiatrists. Moreover, that tool-the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)-has enabled determination of the serious sequelae of delirium, including increased mortality, higher cost, longer length of hospital stay, failure of extubation, and burdensome long-term cognitive impairment. Although prevention and treatment options exist, little data guide current pharmacological approaches to delirium, and nonpharmacological approaches have yet to be fully adopted by ICUs. Ongoing trials will address some of these limitations, but large cohort studies within the ICU are needed to further clarify risk factors and to identify targets to modify the occurrence and course of delirium. Furthermore, consideration of a continuum may better elucidate the true magnitude of acute brain dysfunction in the ICU.