Emergency physician recognition of delirium

To compare the recognition of delirium by emergency physicians based on observations made during routine clinical care with concurrent ratings made by a trained researcher after formal cognitive assessment and to examine each of the four individual features of delirium separately to determine the variation in identification across features.

In a prospective study, a convenience sample of 259 patients, aged ≥65 years, who presented to two urban, teaching hospital emergency departments (EDs) in Western Pennsylvania between 21 June and 29 August 2011, underwent paired delirium ratings by an emergency physician and a trained researcher. Emergency physicians were asked to use their clinical judgment to decide whether the patient had any of the following delirium features: (1) acute change in mental status, (2) inattention, (3) disorganised thinking and (4) altered level of consciousness. Questions were prompted with examples of delirium features from the Confusion Assessment Method. Concurrently, a trained researcher interviewed surrogates to determine feature 1, conducted a cognitive test for delirium (Confusion Assessment Method for the intensive care unit) to determine delirium features 2 and 3 and used the Richmond Agitation and Sedation Scale to determine feature 4.

In the 2-month study period, trained researchers identified delirium in 24/259 (9%; 95% CI 0.06 to 0.13) older patients admitted to the ED. However, attending emergency physicians recognised delirium in only 8 of the 24 and misidentified delirium in a further seven patients. Emergency physicians were particularly poor at recognising altered level of consciousness but were better at recognising acute change in mental status and inattention.

When emergency physicians use routine clinical observations, they may miss diagnosing up to two-thirds of patients with delirium. Recognition of delirium can be enhanced with standardised cognitive testing.