Neurological, Pain, Sedation, and Delirium Assessment
2.5 Delirium Assessment in ICU
2.5.2 Detection
Early detection of ICU delirium is necessary to limit the destructive consequences of an untreated delirium: each subse- quent day of this cerebral syndrome is correlated with a 10%
increase in hospital mortality [41]. The early definition of ICU delirium referred to DSM-IV is based on which different evaluation scales have been developed, nowadays not anymore (Table 2.11).
Table 2.10 Risk factors
Predisposing factors Precipitating factors
Age > 70 Restraint devices
History of depression and/or dementia and/or stroke
Inability to communicate if connected to a ventilator
Drug abuse Visual or hearing impairment Hypo-/hyperthermia Invasive procedures
Hypo-/hypernatremia Catheter indwelled (CVC, urinary catheter, NGT, orotracheal tube, etc.)
Hypo-/hyperthyroidism Drug administration Hepatic and/or renal failure Pain
Septic and/or cardiogenic shock Isolation Emergency surgery Sleep deprivation
Malnutrition Stress
Table 2.11 Comparing DSM classification of delirium [44]
DSM-V DSM-IV
A. Disturbance in attention (i.e., reduced ability to direct, focus, sustain, and shift attention) and awareness (reduced orientation to the environment) B. The disturbance develops over a short
period of time (usually hours to a few days), represents an acute change from baseline attention and awareness, and tends to fluctuate in severity during the course of a day
C. An additional disturbance in cognition (e.g., memory deficit, disorientation, language, visuospatial ability, or perception)
D. The disturbances in Criteria A and C are not better explained by a pre- existing, established, or evolving neurocognitive disorder and do not occur in the context of a severely reduced level of arousal such as coma E. There is evidence from the history,
physical examination, or laboratory findings that the disturbance is a direct physiological consequence of another medical condition, substance intoxication or withdrawal (i.e., due to a drug of abuse or to a medication), or exposure to a toxin or is due to multiple etiologies
A. Disturbance of consciousness (i.e., reduced clarity of awareness of the environment) with reduced ability to focus, sustain, or shift attention B. A change in cognition or
the development of a perceptual disturbance that is not better accounted for by a pre-existing,
established, or evolving dementia
C. The disturbance develops over a short period of time (usually hours to days) and tends to fluctuate during the course of the day D. There is evidence from
the history, physical examination, or laboratory findings that the disturbance is caused by the direct physiological consequences of a general medical condition
The Confusion Assessment Method for the ICU (CAM-ICU) and the Intensive Care Delirium Screening Checklist (ICDSC) are strongly recommended for delirium assessment by the 2013 PAD guidelines, although there are several scales available to assess this syndrome [19].
The CAM-ICU [45] is a part of the neurological evaluation which accounts different levels. First of all it is necessary to assess the level of consciousness by a validated scale (authors recommend the RASS). The second stage is the evaluation of content of consciousness. If the patient is sedated (RASS = −4 or −5), it is impossible to assess because of patient’s unrespon- siveness. These levels are defined as coma, and in these cases we don’t use the CAM-ICU but we describe the patient as not evaluable.
If sedation is mild (RASS ≥−3), patients show some respon- siveness which enables to evaluate their thoughts and the pres- ence of delirium.
The CAM-ICU analyzes four aspects:
1. Acute onset or fluctuating course 2. Inattention
3. Altered level of consciousness 4. Disorganized thinking
The ICDSC (Table 2.12) is a scale for delirium stratification, but it can also be used as a diagnostic scale, and the scale’s application is easy and quick [46]. The ICDSC consists of eight observed variables that are compared with the assessment of the previous day, and increasing values on the ICDSC are compat- ible with severity stratification. In addition, the ICDSC is useful in the diagnosis of subsyndromal delirium [47].
If the score is 0, there is no delirium; from 1 to 3, there is
“subsyndromal delirium;” and from 4 to 8, there is presence of delirium.
The ICDSC has been demonstrated to be a good scale to assess and monitor for delirium and may be preferred since it does not score changes in wakefulness and attention directly attributable to recent sedative medication as positive ICDSC points.
Studies have demonstrated that the ICDSC has a high sensi- tivity (99%) but low specificity (64%) for the diagnosis of delirium when compared to formalized psychiatric assessment.
The CAM-ICU has a lower sensitivity (93%), but higher specificity (96%) than ICDSC, and may correlate more strongly with patient outcome than ICDSC. The use of sedation and
Table 2.12 Intensive Care Delirium Screening Checklist (ICDSC)
Category Description Points
Altered level of consciousness
(a) Drowsy and requires mild to moderate stimulation for response
(b) Hypervigilant (no points are given for a sleeping state)
+1
Inattention Patient displays a level of inattention, including distractibility by external stimuli, difficulty keeping up with conversations, or difficulty shifting focus
+1
Disorientation Evident mistake in time, person, or place +1 Hallucination,
delusion, or psychosis
Any indication of hallucinations (grabbing for an unseen object), delusion, or gross impairment in reality testing
+1
Psychomotor agitation or retardation
(a) Hyperactivity that requires use of sedative drugs or restraints to control potential danger to the patient (b) Hypoactivity or clinically noticeable
psychomotor slowing
+1
Inappropriate speech or mood
Patient displays inappropriate speech or mood
+1 Sleep/wake cycle
disturbance
Patient sleeps <4 h during the night, has frequent awakenings (not related to medical staff-initiated awakenings), or sleeps throughout most of the day
+1
Symptom fluctuation Fluctuation of any of the manifestations of any item or symptom within a 24 h period (i.e., between shifts)
+1
analgesia in the ICU can lead to diagnose a form of drug- induced, hypoactive delirium. Despite its better outcome, such deliric conditions deserves the same attention and promp treat- ment as other ICU delirium features.
ICU delirium assessment should be performed once per shift or whenever a mental status change occurs.
It’s important to use validated tools when changes in sedative or analgesic medication occur, when anesthesia ends its effec- tiveness, when changes in state of conscience occur, or when patients show an acute change of their neurological state [48].