Abstract

Delirium is a common syndrome in critically ill patients and it has significant impact on morbidity, mortality and health economics. Patients are usually either agitated (hyperactive delirium), lethargic and withdrawn (hypoactive delirium) or fluctuate between these two subtypes.

Formal diagnostic criteria for delirium are described in the American Psychiatric Association’s (APA) Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (American Psychiatric 2013) (DSM-5) and the World Health Organization’s (WHO) International Classification of Diseases and Health Related Problems Tenth Revision (ICD-10) (World Health Organization 2016). The reported incidence of delirium within critical care varies from 20-50% in non-ventilated patients to as much as 81.7% in mechanically ventilated patients. The incidence of delirium increases when patients require mechanical ventilation, andwith increasing illness severity. Being delirious is also associated with an increased length of hospital stay and increased duration of mechanical ventilation. Studies which have included long-term follow-up also suggest that patients who have been delirious during their ICU admission have higher mortality rates following hospital discharge. Delirium in ventilated patients was associated with a 1.4-fold and 1.3-fold increase in ICU and total hospital costs.

Like all monitoring devices used by ICU doctors it is necessary to use monitoring systems or methods to assess brain dysfunction in delirium. ICU doctors should familiarize themselves with two well accepted diagnostic tools. They are Intensive Care Delirium Screening Checklist (ICDSC) and the Confusion Assessment Method for the ICU (CAM-ICU). ICDSC is composed of eight components and each patient is assigned a score from 0 to 8 . A cut-off score of 4 has sensitivity 99% and specificity 64% for identifying delirium. While measuring delirium status using CAM ICU, fluctuations of baseline mental status are scored using Richmond- Agitation – Sedation scale (RASS)18 .If score is more than -4 (-3 through +4) then should proceed to next step of CAM ICU which is inattention and disorganized thinking or altered level of consciousness. If RASS is -4 or -5 then CAM- ICU is not applicable. Altered mental status is considered if RASS score is anything other than zero. ICDSC and CAM-ICU allow non- psychiatric physicians and nurses to diagnose delirium in ICU patients rapidly and reliably even when patient cannot speak because of endotracheal intubation.

Clinical Practice Guidelines for the Sustained Use of Sedatives and Analgesics in the Critically Ill Adult’ was published in 2002 by the Society of Critical Care Medicine (SCCM). These were updated in 2013, recognizing the interconnected relationship between delirium and the analgesic and sedative agents used to manage critically ill patients. The latest guidelines focus on the management of pain, delirium and agitation (PAD 2013) and include recommendations on the use of validated delirium screening tools (Barr et al. 2013).