Pain, Agitation/Sedation, Delirium, Immobility, Sleep Disruption, and Neuromuscular Blockade

of delirium. Delirium is also associated with up to a 3-fold increase in mortality, increase in cognitive

decline, delay in cognitive recovery, and increased likelihood of being discharged to a nursing home. Two

studies found that a longer duration of delirium was independently associated with worse activity of daily

2014;42:369-77; N Engl J Med 2013;369:1306-16). A retrospective study reported increased difficulty in

the weaning of mechanical ventilation when delirium was detected in patients during the first spontaneous

weaning trial compared with in patients who did not have delirium (Respirology Nov 2015;1-8).

The underlying pathophysiology of delirium is not well understood; however, it may involve a complex

set of factors:

Cerebral hypoperfusion and alterations in cerebral blood flow

Degradation of the blood-brain barrier, causing influx of inflammatory cytokines and microvascular

thrombosis

Depletion in central neurotransmitters (e.g., dopamine, norepinephrine, serotonin)

Medication withdrawal

identified as risk factors for developing delirium in the ICU, extracting from only a strong or moderate

Age

Preexisting dementia

History of baseline hypertension

APACHE II (Acute Physiology and Chronic Health Evaluation II) score

Delirium on the previous day

Emergency surgery

Mechanical ventilation

Organ failure

(Poly)trauma

Other reported risk factors or precipitants:

Infection

Dehydration or malnutrition

Sleep deprivation

Lack of exposure to sunlight

Lack of personal interaction

Physical restraints or insertion of catheters or tubes

Medication-induced altered mental status – Although the development of delirium is considered

multifactorial, any patient who presents with a change in mental status should have his or her

medications and doses immediately scrutinized as part of the initial workup for delirium. Several classes

of medications have long been recognized for their effects on mental status and cognitive function, in

or out of the ICU. These medications have the potential to affect a patient’s level of consciousness

or course of delirium at any point in the patient’s hospital stay. Anticholinergics, benzodiazepines,

opiates, antipsychotics, antispasmodics, anticonvulsants, corticosteroids, and others should be used

with caution in a hospitalized patient, with close monitoring of the patient’s cognitive adverse effects.

Because renal and hepatic function may fluctuate throughout an ICU stay and affect the clearance

of these medications, doses must be thoughtfully titrated. Research on the degree of impact these

medications have on the overall course of sedation and delirium in the ICU is difficult to characterize,