Table 1 Instruments for the diagnosis of delirium in the ICU

Abbreviated Cognitive Test for delirium [36]

Total score obtained by summing up two content scores: attention (range 0–14) and memory (range 0–10)

Memory is assessed by recognition of pictured objects. Attention is assessed using the visual memory span subtest of the Wechsler Memory Scale-Revised.

<11

Confusion Assessment Method for the ICU [8]

The instrument assesses four features: 1) acute onset of mental status changes or fluctuating course; 2) inattention; 3) disorganized thinking; 4) altered level of consciousness

Feature 1: assess for acute change in mental status, fluctuating behavior or serial Glasgow Coma Score or sedation ratings over 24 hours. Feature 2: assess using picture recognition or random letter test. Feature 3: assess by asking the patient to hold up a certain number of fingers. Feature 4: rate level of consciousness from alert to coma.

Features 1 or 2 are positive, along with either Feature 2 or Feature 4

Intensive Care Delirium Screening Checklist [37]

Checklist of eight items: altered level of consciousness, inattention, disorientation, hallucination or delusion, psychomotor agitation or retardation, inappropriate mood or speech, sleep/wake cycle disturbance, and symptom fluctuation. The presence of each item of the scale is attributed one point.

The scale is completed based on information collected from the entire shift. Items scored in a structured way with definitions available for every item.

≥4

Neelon and Champagne Confusion Scale [38]

The scale is divided into three subscales: 1) information processing (attention, processing and orientation); 2) behavior (appearance, motor and verbal behavior); and 3) physiological condition (vital function, oxygen saturation, and urinary incontinence). The subscales contain a total of nine items. The score ranges from 0 through 30. Each item is scored according to the severity of the symptom.

Information based on observations by nurses at bedside. Items scored in a structured way with definitions available for every item.

Moderate to severe delirium (0–19); mild to early delirium (20–24); at high risk for delirium (25–26); no delirium (27–30)

Delirium Detection Score [39]

Eight criteria: agitation, anxiety, hallucination, orientation, seizures, tremor, paroxysmal sweating, and altered sleep-wake rhythm. Each criterion has four severity levels and accounts for 0, 1, 4, or 7 points depending on severity of the symptom.

Assessment performed during each shift by the treating physician and nurse who used a form with the items and definitions. The highest score in each shift was recorded. Items scored in a structured way with definitions available for every item.

>7

Nursing Delirium Screening Scale [40]

This scale contains five items: disorientation (verbal or behavioral manifestation of not being oriented to time or place or misperceiving persons in the environment); inappropriate behavior (behavior inappropriate to place and/or for the person, such as pulling at tubes or dressings, attempting to get out of bed when that is contraindicated, and the like); inappropriate communication (communication inappropriate to place and/or for the person, such as incoherence, noncommunicativeness, nonsensical or unintelligible speech); illusions/hallucinations (seeing or hearing things that are not there or distortions of visual objects); and psychomotor retardation (delayed responsiveness or few or no spontaneous actions/words). Symptoms are rated from 0 to 2 based on the presence and intensity of each symptom. Total score is obtained from the addition of the symptom ratings. Maximal score is 10.

Assessment performed per shift by bedside nurses.

>1