Intensive Care Unit Delirium

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Incidence

The incidence of ICU delirium varies widely from 16% to 89%.3, 4, 5, 6, 7, 8, 9, 10 The variation is primarily attributable to differences in study population, use and choice of screening instrument, diagnostic criteria, and risk factors, such as sedative agents administered. Fig. 2 illustrates the varying incidence of ICU delirium in various subpopulations using the Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC), 2 validated

Pathophysiology and risk factors

The pathophysiology of ICU delirium is not well understood. It is thought to be multifactorial and many theories have been postulated including a local inflammatory response of the brain to insult, such as infection, resulting in alterations in neuronal activity; imbalances in the neurotransmitters modulating cognition (ie, dopamine, acetylcholine, γ-aminobutyric acid, and/or serotonin), with predominately a relative excess of dopamine in relation to acetylcholine; reduced cerebral perfusion;

Clinical relevance: morbidity and mortality

ICU delirium has been directly correlated with patient morbidity and mortality. In a single-center, prospective, cohort study including 224 mechanically ventilated adult MICU or coronary ICU (CICU) patients, the presence of delirium (CAM-ICU positive) was associated with a 3.2-times higher risk of death within 6 months compared with patients who were never delirious (adjusted hazard ratio 3.2 [1.4–7.7], P<.05). The absolute 6-month mortality in the delirious and never-delirious study groups was

ICU Delirium assessment

In the past 5 years, there has been an increase in the awareness and assessment of ICU delirium. A survey of critical care professionals (n = 912) conducted in 2001–2002 aimed to assess the practices and beliefs of the medical community regarding ICU delirium.30 Overall, 92% of respondents reported that delirium is a significant ICU problem, and 78% believed delirium is underdiagnosed; however, only 40% routinely screened for delirium, with a mere 16% reporting use of a specific delirium

Nonpharmacologic Treatment

Nonpharmacologic treatment should be incorporated into the management of ICU delirium in all patients, regardless of delirium subtype. The key to nonpharmacologic management is first recognition of potential and existing problem areas followed by intervention to correct or modify the situation. This process entails evaluation and assessment of 3 major areas: the presence of barriers between patient and practitioner, environmental modification, and ICU care (Fig. 5). The ensuing discussion of

Practice implications

Health care professionals in the ICU are becoming more aware of the effect of delirium on critical care outcomes, as shown by an increase in self-reported delirium assessment. However, in order for an institution to be successful in addressing delirium in the ICU, several key components must be present. It is vital to appoint champions to help spearhead delirium initiatives. A delirium champion representative from each critical care discipline (eg, nursing, physician, pharmacy) should be

Summary

Identification and prompt management of ICU delirium are vital in promoting safety for patients and their caregivers. Critically ill adult patients, both mechanically ventilated and non-mechanically ventilated, are at a high risk for the development of delirium during their ICU stay with an incidence of up to 89%. ICU delirium has been linked to long-term cognitive impairment and has been shown to significantly increase 6-month mortality, ICU length of stay, time on the ventilator, and ICU and

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    The authors have no conflicts of interest regarding this publication.

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