Delirium in the intensive care unit: An under-recognized syndrome of organdysfunction

The intensivist should think of delirium, or acute central nervous system d ysfunction, as the brain's form of "organ dysfunction." Delirium is extreme ly common in intensive care unit (ICU) patients due to factors such as como rbidity, critical illness, and iatrogenesis, This complication of hospital stay is extremely hazardous in older persons and is associated with prolong ed hospital stays, instirutionalization, and death. Neurologic dysfunction com promises patients' ability to be removed from mechanical ventilation or achieve full recovery and independence. Yet ICU nurses and physicians are usually unaware of the presence of hypoactive delirium and only recognize t his disturbance in agitated patients (hyperactive delirium). More important ly, there are few studies that have included ICU patients in the assessment or prevention of delirium. This article reviews the definition and salient features of delirium, its primary risk factors, a newly validated instrume nt for delirium assessment that is being developed for ICU nurses and physi cians, and pharmacological agents associated with the development of deliri um and used in its management.