(see also Richmond-Agitation Sedation Scale; Sedation Monitoring, ABCDE Bundle)
Delirium is a serious disruption in mental abilities that results in confused thinking, behavior changes (sometimes including hallucinations), reduced awareness of the environment, and emotional disturbances. It usually develops over a short period of time (hours to days) and may fluctuate during a 24-hour period, although symptoms are usually worse during the night. It is a reversible state and is the direct consequence of a medical condition, substance intoxication or withdrawal, use of a medication, toxin exposure, or a combination of these factors. Comatose patients often, but not always, progress through a period of delirium before recovering to their baseline mental status. Delirium has been found to lengthen hospital stays, prolong time on the ventilator, increase the cost of care, and add to morbidity and mortality.
The Confusion Assessment Method (CAM) was created in 1990 and has since been adapted for use in ICU patients (CAM-ICU) who are either on or off the ventilator. It is used in conjunction with the Richmond Agitation-Sedation Scale (RASS).
CAM grading: The patient is graded positive for delirium if point 1 and point 2 are present, along with either point 3 or point 4 or both. Conversely, if the patient tests negative for point 1 and exhibits <2 errors on point 2, there is no need to continue the assessment, as it is established that no delirium exists.
Does it still count as fluctuation in mental status or change from baseline mental status when a patient is on sedatives? Yes. Alteration in mental status includes those who are chemically induced by the healthcare team, including fluctuation due to titration of sedatives. This is not the patient's usual mental status. It is often difficult to completely distinguish a disease-induced change from a drug-induced change in mental status.
And what about the level of consciousness? At deeper levels of consciousness (RASS −4 and −5), it is difficult to assign a number because the patient is unresponsive. These levels are referred to as coma or stupor, and in those situations, the CAM-ICU cannot be implemented and the patient is referred to as “unable to assess.”
Delirium assessment is essential to maintain patient safety and minimize the effects and duration of the condition. While antipsychotic medications have been used to treat the condition, recent studies show no improvement in delirium, length of stay, or survival using these drugs. Evidence-based strategies for prevention and treatment of ICU delirium are shown in Figure 1.20.