Geriatrics/original researchDiagnosing Delirium in Older Emergency Department Patients: Validity and Reliability of the Delirium Triage Screen and the Brief Confusion Assessment Method
Introduction
Delirium is an acute disturbance in attention accompanied by a rapid change in cognition that affects 1.5 million older emergency department (ED) patients in the United States annually.1, 2, 3 This form of acute brain dysfunction often leads to devastating consequences such as death and accelerated cognitive decline.4, 5, 6 Unfortunately, delirium is frequently missed by health care professionals in all clinical settings,2, 7 which is especially the case in the ED, where it is missed 57% to 83% of the time.2, 8, 9, 10, 11, 12, 13
The ED is the nexus of the health care system.14 Missing delirium in this setting has the potential to compromise patient safety and may have downstream implications for clinical care and patient health.15 Because delirious patients are less likely to provide an accurate reason of why they are in the ED, missing delirium may lead to inadequate diagnostic evaluations, inappropriate dispositions, and delays in the diagnosis of their underlying medical illness.16, 17 Up to 25% of delirious ED patients are discharged home2, 12, 18 and are less likely to comprehend their discharge instructions, which may lead to decreased compliance.16, 19 Finally, if patients are admitted, delirium that is missed in the ED will also be missed in the inpatient setting in more than 90% of cases.13
Delirium is often clinically silent and will remain unrecognized without a formal delirium assessment. Most health care professionals do not screen for delirium in their clinical practice13, 20 because there is a dearth of brief and easy-to-use assessments. Many existing assessments take more than 5 minutes to complete and may not be feasible to perform in busy clinical environments.21 Because physicians often evaluate a large number of patients in a short period of time, nonphysician hospital personnel (nurses, patient care technicians, etc) who have more exposure to patients may be better suited for delirium screening. Unfortunately, most delirium assessments are subjective and their diagnostic accuracy may be reduced when used by nonphysicians.22, 23
One method to improve delirium detection would be to use a 2-step approach: a sequential testing strategy that uses brief, valid, and reliable delirium assessments that can be performed by health care professionals of all clinical backgrounds. The first step would be to perform a very brief (<20 seconds), highly sensitive delirium screen to rule out delirium. This rapid rule-out screen can be incorporated into the ED triage assessment or can be part of the initial nursing assessment after the patient has been assigned an ED bed. A negative screen result would rule out delirium, reduce the number of formal delirium assessments needed, and enhance screening efficiency. A positive screen result would trigger a formal delirium assessment performed by another health care provider (ie, physician) at the patient's bedside that would be highly specific to rule in delirium. Ideally, this rule-in assessment should be brief (<1 minute) to maximize feasibility. We developed Delirium Triage Screen (DTS) and the Brief Confusion Assessment Method (bCAM) to serve as the rule-out and rule-in tests for the 2-step approach to delirium surveillance (Figure 1), respectively.
We sought to determine the diagnostic performances of these novel assessments in older ED patients, using the psychiatrist's assessment as the reference standard.
Section snippets
Study Design and Setting
This was a prospective observational study conducted at a tertiary care, academic ED. The local institutional review board reviewed and approved this study. Informed consent from the patient or an authorized surrogate was obtained whenever possible. Because this was an observational study and posed minimal risk to the patient, the local institutional review board granted a waiver of consent for patients who were both unable to provide consent and without an authorized surrogate available in the
Results
A total of 953 patients were screened, 406 patients met enrollment criteria (Figure 2), and of those enrolled, 50 (12.3%) received a diagnosis of delirium by the psychiatrist. Baseline characteristics can be seen in Table 1; 24 patients (5.9%) were from assisted living facilities, 11 (2.7%) were from nursing homes, and none received mechanical ventilation. During the study period, 22,168 potentially eligible ED patients who were aged 65 years or older presented to the ED. Both enrolled and
Limitations
This study has several limitations. Because screening more than 22,000 older ED patients during a 2.5-year period was not feasible, especially with the psychiatrists' limited availability, we enrolled a convenience sample, which may have introduced selection bias. According to the higher Emergency Severity Index scores and admission rates, the enrolled cohort may have had higher severities of illness. Though this may have introduced spectrum bias, the DTS's and bCAM's diagnostic performances
Discussion
Delirium is missed at an alarmingly high rate because health care professionals do not screen for it.2, 8, 9, 10, 11, 12, 13 This compromise in the quality and safety of care occurs15 because brief (< 1 minute) and easy-to-use delirium assessments are not readily available. This investigation provides a novel and simple 2-step approach to delirium surveillance that is reliable and valid and could significantly improve patient care and health outcomes. The DTS (spell lunch backwards) and bCAM
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Author contributions: JHH, JFS, RDS, ABS, and EWE conceived the trial. JHH, AW, AS, JFS, RDS, ABS, and EWE participated in the study design. JHH, AW, and JS recruited patients and collected the data. JHH, AS, RDS, and AJG analyzed the data. All authors participated in the interpretation of results. JHH drafted the article and all authors contributed to its critical review and revision. JHH takes responsibility for the paper as a whole.
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article as per ICMJE conflict of interest guidelines (see www.icmje.org). The authors have stated that no such relationships exist. Dr. Han and this study were funded by the Emergency Medicine Foundation Career Development Award and National Institutes of Health K23AG032355. This project was also supported by the National Center for Research Resources, grant UL1 RR024975-01, and is now at the National Center for Advancing Translational Sciences, grant 2 UL1 TR000445-06. Dr. Vasilevskis was supported in part by the National Institutes of Health (K23AG040157). Dr. Ely was supported in part by the National Institutes of Health (R01AG027472 and R01AG035117), and a Veteran Affairs MERIT award. Drs. Vasilevskis, Schnelle, Dittus, and Ely are also supported by the Veteran Affairs Tennessee Valley Geriatric Research, Education, and Clinical Center (GRECC). The funders played no role in data collection, analysis, or interpretation of findings or the decision to submit the article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health, Emergency Medicine Foundation, and Veteran Affairs.
Publication dates: Available online July 31, 2013.
Please see page 458 for the Editor's Capsule Summary of this article.