Delirium goes unrecognized or undiagnosed in up to 72% of cases in hospitalized patients (Collins 2010). One of the reasons may be that commonly used screening tests for delirium may not be brief enough or may require specific training for administration. While traditional validated tools like the CAM and CAM-ICU remain key components of any programs addressing delirium, we wholeheartedly support the exploration of tools that can be administered briefly and by those without extensive training. Such tools could likely greatly increase the detection of delirium so that appropriate management strategies can be put in place.
We have discussed such rapid screening tools in prior columns (our Whats New in the Patient Safety World columns for August 2014 A New Rapid Screen for Delirium in the Elderly and July 2016 )
Since that last column there have been a few more studies on rapid screening tools for delirium. One study evaluated the brief Confusion Assessment Method (bCAM) in a German emergency department setting and administered during the daily work routine (Baten 2018). The bCAM showed 93.8% specificity but only moderate (65.2%) sensitivity. Positive and negative likelihood ratios were 10.5 and 0.37, respectively, But delirium was missed in 10 of 16 cases, since the bCAM did not indicate altered levels of consciousness and disorganized thinking. Nevertheless, the authors felt that application of the bCAM most likely improves the delirium detection rate. However, they cautioned it should only be applied by trained physicians to maximize diagnostic accuracy and hence improve the bCAM's sensitivity.
Another study reviewed the literature on attention, arousal and other rapid bedside screening instruments for delirium in older patients (Quispel-Aggenbach 2018). The authors found wide variability in specificity and sensitivity. Two arousal assessment tools - the Observational Scale of Level of Arousal (OSLA) and Richmond Agitation and Sedation Scale (RASS) had sensitivity and specificity >80%. Both those tools can be easily administered by nurses during daily interaction with patients.
We hope youll go back to our Whats New in the Patient Safety World columns for August 2014 A New Rapid Screen for Delirium in the Elderly and July 2016 for discussions on the other tools that have been used for rapid screening for delirium. But the two new studies demonstrate we still have a need for better screening tools that can be rapidly and easily administered during routine care.
Some of our prior columns on delirium assessment and management:
Collins N, Blanchard MR, Tookman A, Sampson EL. Detection of delirium in the acute hospital. Age Ageing 2010; 39 (1): 131-135
Baten V, Busch J-J, Busche C, et al. Validation of the Brief Confusion Assessment Method for Screening Delirium in Elderly Medical Patients in a German Emergency Department. Academic Medicine 2018; First Published: 08 May 2018
Quispel-Aggenbach DWP, Holtman GA, Zwartjes HAHT, et al. Attention, Arousal and Other Rapid Bedside Screening Instruments for Delirium in Older Patients. A Systematic Review of Test Accuracy Studies. Age Ageing 2018; 47(5): 644-653