Intensive care unit delirium: a review of the literature

The recent literature regarding intensive care unit (ICU) delirium and updated clinical practice guidelines are reviewed.

Recent studies show that ICU delirium in critically ill patients is an independent predictor of higher mortality, longer ICU and hospital stay, and is associated with multiple clinical complications. Delirium has been reported to occur in greater than 80% of hospitalized critically ill patients, yet it remains an underdiagnosed condition. Several subtypes of delirium have been identified including hypoactive, hyperactive, and mixed presentation. Although the exact mechanism is unknown, several factors are thought to interact to cause delirium. Multiple risk factors related to medications, acute illness, the environment, and patient characteristics may contribute to the development of delirium. Practical bedside screening tools have been validated and are recommended to identify ICU patients with delirium. Nonpharmacologic interventions such as early mobilization have resulted in better functional outcomes, decreased incidence and duration of delirium, and more ventilator-free days. Data supporting pharmacologic treatments are limited.

Clinicians should become familiar with tools to identify delirium in order to initiate treatment and remove mitigating factors early in hospitalization to prevent delirium. Pharmacists are in a unique position to reduce delirium through minimization of medication-related risk factors and development of protocols.