What is Delirium Screening?

Background

Delirium occurs commonly in hospitalized older patients but is poorly recognized. Though there is an abundance of confirmed delirium screening tools, it is unclear which tool best suits particular populations.

Purpose

To assess validation studies of delirium screening tools in non--critically ill hospital inpatients and supply guidance on the selection of screening tool.

Methods

The MEDLINE, CINAHL, and PsychInfo databases were searched for studies comparing delirium bedside screening tools using either the Diagnostic and Statistical Manual or International Classification of Diseases defined identification of delirium in hospital inpatients. Information was also drawn from conference proceedings and discussion with delirium researchers.

Results

The majority of studies were conducted across a wide variety of inpatient settings internationally in elderly inpatients, including patients with dementia but most excluded nonnative language speakers.

Implications

The Confusion Assessment Method has been the most popular instrument to identify delirium, however, specific training must ensure optimum performance. The Delirium Rating Scale and its revised version performed best in the psychogeriatric population but requires an operator with psychiatric training. The Nurses' Delirium Screening Checklist appears best suited to the surgical and recovery room setting. The Memorial Delirium Assessment Scale, while demonstrating good measures of validity at the surgical and palliative care setting, may be used a measure of delirium severity. The 4As Evaluation performed well when delirium was superimposed on dementia, but it requires further study.

Delirium is a serious disorder of attention, cognition, and psychomotor activity that commonly affects older folks. The reported prevalence of delirium during entrance in the hospitalized adult population is 3%--29% ( Siddiqi, House, & Holmes, 2006 ). The co-occurrence of delirium in patients with dementia is particularly high in hospitalized older adults (22%--89 percent, Fick, Agostini, & Inouye, 2002 ).

The overall risk of adverse outcome as a result of hospitalization in the elderly people, especially those from residential care facilities, is already high for functional decline and falls ( Friedman, Mendelson, Bingham, & McCann, 2008 ). The negative outcomes for delirious patients may be even graver. They include multiple medical complications, higher lengths of stay, the chance of not returning to independent living, and death ( Cole et al., 2002; Elie et al., 2000; Inouye, 2006 ). Delirium superimposed upon dementia has been shown to prolong hospital stay and be associated with both cognitive and functional decline ( Fick, 2013 ). Patients with dementia are particularly difficult to evaluate for delirium ( Powers et al., 2013 ). However, there are definite advantages to early detection and targeted treatment ( Chong, Chan, Tay, & Ding, 2014; Lundstrom et al., 2005; Mudge, Maussen, Duncan, & Denaro, 2013 ). It is thus imperative that delirium is correctly identified and managed to decrease the substantial morbidity and mortality, particularly in elderly folks.

Delirium was described more than 2000 years back and is a prevalent condition in the hospitalized elderly population. It still remains underrecognized (Inouye, Westendorp, & Saczynski, 2014) and is often misdiagnosed (Inouye, 2006; Voyer, Cole, McCusker, St-Jacques, & Laplante, 2008; Wand et al., 2013). By way of example, a new Australian study demonstrated that detection of delirium by staff was poor, with employees correctly identifying just 23 percent of cases with delirium despite a targeted multimodal educational intervention ( Wand et al., 2014). Delirium remains understudied in relation to the percentage of its disease burden ( MacLullich et al., 2013 ).

Prior to its inclusion in the DSM, delirium was described in the literature under different eponyms, such as acute confusional state, toxic encephalopathy, and toxic psychosis. The variable terms used led to much confusion in the detection of delirium and made it difficult to interpret the published literature ( Hall, Meagher, & MacLullich, 2012 ). Over the last three decades, there have been significant developments in the understanding of delirium and with it, revisions in the delirium diagnostic criteria (American Psychiatric Association 1987, 1994, 2013).

There are now numerous screening tools validated for the evaluation of delirium. A recent review by Grover and Kate (2012) comprehensively identified and evaluated 38 separate instruments in use for screening, diagnosis, assessing cognitive function, assessing motor symptoms, risk factors, and grading severity of and quantifying the distress associated with delirium. In response to the limitations of current screening measures, newer tools have emerged and are being validated ( Lin et al., 2015; MacLullich, Ryan, & Cash, 2011; Sands et al., 2010 ). The abundance of tools available can make it difficult for the clinicians to choose which tool to use and in what context.

Therefore, the primary purpose of this review was to identify, compare, and evaluate validation studies of delirium screening tools used in hospital inpatients. A secondary aim was to give guidance regarding the clinical applicability of the reviewed screening tools to certain patient populations.

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