Delirium is defined in the American Psychiatric Association’s (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV as a disturbance of consciousness and cognition that develops over a short period of time (hours to days) and fluctuates over time. It is a common manifestation of acute brain dysfunction in critically ill patients, and occurs in up to 80% of the sickest intensive care unit (ICU) populations. People with delirium are unable to think clearly, have decreased attention, and may have auditory and/or visual hallucinations.
Critically ill patients are subject to numerous risk factors for delirium. Some of these, such as exposure to sedative and analgesic medications, may be modified to reduce risk. Although dysfunction of other organ systems continue to receive more clinical attention, delirium is now recognized to be a significant contributor to morbidity and mortality in the ICU, and it is recommended that all ICU patients be monitored using a validated delirium assessment instrument such as, The CAM-ICU.
The CAM-ICU is modified from the Confusion Assessment Method (CAM) and assesses four features: acute change or fluctuation in mental status from baseline, inattention, altered level of consciousness, and disorganized thinking.
Delirium in the ICU is quite common. The pathophysiology of delirium is poorly understood but it is theorized to be a neurobehavioral manifestation of neurotransmitter imbalance.
Some causes of delirium include: poor oxygen perfusion of the brain, chemical changes in the brain, medications, infections or sepsis, and alcohol withdrawal.
People who are more likely to get delirium are those who have: dementia, depression, poor eyesight and/or hearing, heart failure, infection/sepsis, or take certain high-risk medicines.
Among medical ICU patients, delirium is associated with multiple complications and adverse outcomes, including self-extubation and removal of catheters, failed extubation, prolonged hospital stay, increased health care costs, and increased mortality.
When delirium is diagnosed or suspected, the underlying causes should be sought. Components of delirium management include supportive therapy and pharmacological management. Reorientation techniques or memory cues such as a calendar, clocks, and family photos may also be helpful. The environment should be stable, quiet, and well lit. Physical restraints should be avoided. Delirious patients may pull out intravenous lines, climb out of bed, and may not be compliant. Perceptual problems lead to agitation, fear, combative behavior, and wandering. Severely delirious patients should never be left alone or unattended and may benefit from constant observation to help avoid the use of physical restraints.