Assessment and Prevention of Delirium in ICU

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Assessment and Prevention of Delirium in ICU - #46

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Adult ICU patients should be routinely monitored for delirium.

Assessment

Presence of delirium is often underestimated as it frequently presents as a hypoactive (psychomotor retardation, low level of alertness) rather than a hyperactive state (psychomotor agitation, disruptive behaviors). Given the high incidence and under diagnosis, adult ICU patients with risk factors should be routinely monitored for delirium by combined use of the following:

  • Clinical history (risk and precipitating factors identification).
  • Behavioral observation (level of alertness, psychomotor activity).
  • Cognitive assessment (delirium assessment tools).
Risk Factors
Non-modifiable Modifiable Precipitating Factors in the ICU (1)
  • Dementia
  • History of delirium
  • Advancing age
  • History of stroke
  • Severe hypertension
  • Neurological disease
  • Falls or gait disorder
  • Multiple comorbidities 
  • Male gender
  • Chronic renal disease
  • Chronic hepatic disease
  • Sensory impairment
  • Immobilization
  • Medications (drugs with anticholinergic effects, sedative/hypnotics)
  • Concurrent illness (including infection)
  • Metabolic derangement
  • Fluid/electrolyte imbalance
  • Surgery (usually cardiac and orthopedic surgery)
  • Environment (e.g., admission to ICU)
  • Pain
  • Emotional distress
  • Sustained sleep deprivation
  • Sepsis and septic shock
  • High severity of illness on presentation
  • Coma
  • Mechanical ventilation
  • Use of parenteral sedative and opioid medications
  • Withdrawal from alcohol and benzodiazepines

Assessment Tools: Specifically designed for use in ICU patient populations, the Confusion Assessment Method (CAM-ICU) evaluates cognitive abilities by assessing onset and course of symptoms, inattention, disorganized thinking, and altered level of consciousness (1,4,5). It has been validated and has a sensitivity of 94-100% and specificity of 90-95%.

The Delirium Assessment Scale (MDAS) can subsequently be utilized once a diagnosis of delirium is made to determine severity (4). The Intensive Care Delirium Screening Checklist (ICDSC) is another valid and reliable delirium monitoring tool (1,5)

Prevention strategies:  Prevention of delirium is paramount and includes both non-pharmacologic and pharmacologic considerations. Interventions concentrate on adjustment of modifiable risk factors.

Modifiable Risk Factor Preventive Strategy
  • Sensory impairment
  • Immobilization
  • Medications
  • Infections
  • Metabolic derangement
  • Fluid/electrolyte imbalance
  • Pain
  • Emotional distress
  • Sustained sleep deprivation
  • Optimize communication (hearing amplifier, appropriate lighting, maintain eye contact, etc.).
  • Early mobilization. PT/OT evaluation.
  • Minimize use of medications with anticholinergic effects. When using sedatives, use the lower dose needed and for the shortest time necessary.
  • Atypical antipsychotics (quetiapine, risperidone) and dexmedetomidine may reduce duration and severity of delirium in ICU, however, there is no compelling evidence that these agents prevent delirium (1).
  • Prevent common infections (pulmonary, skin, and urinary): Monitor IV access. Pressure ulcer prevention. Respiratory therapy. Early mobilization. Optimize Foley catheter care.
  • Monitor medication/illness progression and correct disorders promptly.
  • Prevent dehydration. Monitor and correct electrolyte derangement promptly (including sodium, calcium, and phosphorus).
  • Implement non-pharmacologic measures. Optimize non-narcotic analgesics. When using opioids, use the lower dose needed and for the shortest time necessary.
  • Counseling. Mental health evaluation.
  • Optimize sleep cycle (based on patient’s routine). When using medications, use the lower dose needed and for the shortest time necessary.

 

Context

Critically ill geriatric patients requiring ICU care.

Action

Delirium risk assessment, evaluation and prevention of delirium in geriatric patients admitted to the ICU.

Incidence / Prevalence

Delirium is associated with increased mortality, length of stay, increased cost of care and long-term cognitive impairment in adult ICU patients (1). In general, 30-80% of patients admitted to the ICU will experience delirium (2,3). In the geriatric population, however, the incidence is as high as 70-87% (3). The most common risk factor for elderly patients to develop delirium is underlying dementia which is present in 66% of all cases of delirium. It is estimated that 30-40% of cases of delirium are preventable, therefore utilization of prevention strategies is essential (4).

Underlying Sciences

The causes of delirium are still being elucidated, but a few hypotheses are thought to be involved including neurotransmitter imbalance, inflammation, impaired oxidative metabolism, and availability of large neutral amino acids (6). Imbalances of the neurotransmitters dopamine and acetylcholine may cause delirium via neuronal instability and irregular neurotransmission (6). Causes of neurotransmitter imbalance include drug toxicity, inflammation, and acute stress responses (4).  Additionally, inflammation from multiple etiologies may mediate delirium via cytokine and endotoxin transmission across the blood brain barrier; cerebral vasculature may be subsequently compromised during inflammation leading to delirium.  Impaired oxidative metabolism may also explain delirium by altering neurotransmission leading to “cerebral insufficiency” in states of multisystem organ failure. Lastly, a deficiency of large neutral amino acids can cause depletion of neurotransmitters (e.g., norepinephrine and dopamine) (6).

Science Principles

Impaired homeostasis

Objectives

  1. Recognize geriatrics patients at risk of developing delirium.
  2. Describe available tools to diagnose delirium in the ICU.
  3. Describe strategies to prevent delirium in high-risk ICU patients.

Keywords/Tags

References

1.    Barr J, Fraser GL, Puntillo K, et al. Clinical practice guidelines for the management of pain, agitation, and   delirium in adult patients in the intensive care unit. Crit Care Med 2013; 41(1):263-306.

2.   Maldonado JR, Maccioli GA, Riker RR, Dasta JF, Szabo E. (2005). Delirium in the ICU: Prevention and          Treatment. From data presented at symposia and sessions held during the Society of Critical Care          Medicine’s 33rd and 34th Critical Care Congresses. Retrieved from      http://psychiatry.stanford.edu/Psychosomatic/Maldonado'05-Delirium%20in%20ICU.pdf

3.   (2014). Delirium Assessment and Management. American Association of Critical-Care Nurses. Retrieved        from http://www.aacn.org/wd/practice/content/practicealerts/delirium-practice...

4.   Fong TG, Tulebaev SR, Inouye SK. Delirium in elderly adults: diagnosis, prevention, and treatment. Nature Reviews Neurology. 2009; 5(4): 210-220.

5.   Pun BT, Devlin JW. Delirium monitoring in the ICU: Strategies for initiating and sustaining screening efforts. Semin Respir Crit Care Med 2013; 34:179-188.

6.   Girard TD, Pandharipande PP, Ely EW. Delirium in the intensive care unit. Critical Care. 2008; 12 (Suppl 3): S3.

7.   Hyperlinks: http://www.icudelirium.org/docs/CAM_ICU_training.pdf; http://www.delirant.info/DreamHC/Download/MDAS.pdf;  http://www.lhsc.on.ca/Health_Professionals/CCTC/elearning/bedside_sheets_ICDSC_screen_July_2012.pdf

This GFF ___ my competence in geriatrics.

Authors

Gretchen Wagner, Nevin Uysal-Biggs, MD; Tessa Damm, DO; Gabriel Manzi, MD; Bambi Wessel

Author Affiliation

Medical College of Wisconsin, Milwaukee WI

Copyright

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