Delirium


Definition


Epidemiology of Intensive Care Unit (ICU)-Associated Delirium

Prevalence

  • General Comments
    • Prevalence of Delirium in Mechanically Ventilated Patients: 60-80%
    • Prevalence of Delirium in Non-Mechanically Ventilated Patients: 40-60%
  • Clinical Data
    • BRAIN-ICU Study of Patients with Respiratory Failure or Shock in the Medical/Surgical ICU (NEJM, 2013) [MEDLINE]: n = 821)
      • Delirium Developed in 74% of Cases During Hospital Stay
      • Outcomes At 3 Months
        • 40% of Patients Had Impaired Global Cognition Scores that Were 1.5 SD Below the Population Mean, Similar to Scores for Patients with Moderate Traumatic Brain Injury
        • 26% of Patients Had Scores 2 SD Below the Population Mean (similar to scores for patients with Mild Alzheimer’s Disease
      • Outcomes At 12 Months
        • Similar Persistent Cognitive Dysfunction Occurs as in Those with Moderate Traumatic Brain Injury
        • Similar Persistent Cognitive Dysfunction Occurs as in Those with Mild Alzheimer’s Disease
      • Impact of Duration of Delirium
        • Longer Duration of Delirium was Significantly Associated with Worse Global Cognition at 3 and 12 Months and Worse Executive Function at 3 and 12 Months
      • Impact of Sedative Use
        • Use of Sedatives or Analgesics was Not Associated with Cognitive Impairment at 3 and 12 Months
      • Cognitive Dysfunction was Also Independent of Age, Pre-Existing Cognitive Impairment, Presence or Severity of Coexisting Conditions, and Organ Failure During ICU Care

Risk Factors for Intensive Care Unit-Associated Delirium (Synopsis of the National Institute for Health and Clinical Excellence Guideline for Prevention of Delirium; Ann Intern Med, 2011) [MEDLINE]

Baseline Risk Factors

  • Advanced Age
  • APOE-4 Genotype
  • History of Ethanol Use (see Ethanol, [[Ethanol]])
  • History of Depression (see Depression, [[Depression]])
  • History of Hypertension (see Hypertension, [[Hypertension]])
  • History of Tobacco Use (see Tobacco, [[Tobacco]])
  • Immobility/Limited Mobility
  • Pre-Existing Cognitive Impairment
  • Sensory Impairment

Acute Illness-Related Risk Factors

  • Anemia (see Anemia, [[Anemia]])
  • Constipation (see Constipation, [[Constipation]])
  • Dehydration
  • Elevated Inflammatory Biomarkers
  • Fever (see Fever, [[Fever]])
  • High Illness Severity
  • High LNAA Metabolite Levels
  • Hypotension (see Hypotension, [[Hypotension]])
  • Hypoxia (see Hypoxemia, [[Hypoxemia]])
  • Medical Illness: vs surgical illness
  • Metabolic Disturbance
  • Multiorgan Failure
  • Need for Mechanical Ventilation
  • Number of Infusing Medications
  • Pain (see Pain, [[Pain]])
  • Malnutrition (see Malnutrition, [[Malnutrition]])
  • Respiratory Disease
  • Sepsis/Infection (see Sepsis, [[Sepsis]])
  • Sleep Disturbance (see Sleep, [[Sleep]])
    • Sleep Deprivation is Common in Mechanically Ventilated Intensive Care Unit Patients (Chest, 2000) [MEDLINE]
    • Features of Intensive Care Unit-Associated Sleep Disruption
      • Sleep Fragmentation
      • Sleep Spread Throughout the Day
      • Decreased REM
      • Decreased Stage 3 Sleep
    • Consequences of Intensive Care Unit-Associated Sleep Disruption
      • Delirium
      • Impaired Immunity
      • Impaired Wound Healing
  • Use of Several Medications

Hospital-Related Risk Factors

  • Immobility/Limited Mobility
  • Isolation
  • Lack of Visitors
  • Loss of the Day/Night Cycle
  • Sleep Deprivation (see Sleep, [[Sleep]])
    • Sleep Deprivation is Common in Mechanically Ventilated Intensive Care Unit Patients (Chest, 2000) [MEDLINE]
    • Features of Intensive Care Unit-Associated Sleep Disruption
      • Sleep Fragmentation
      • Sleep Spread Throughout the Day
      • Decreased REM
      • Decreased Stage 3 Sleep
    • Consequences of Intensive Care Unit-Associated Sleep Disruption
      • Delirium
      • Impaired Immunity
      • Impaired Wound Healing
  • Use of Medications
    • Benzodiazepines (see Benzodiazepines, [[Benzodiazepines]])
    • Corticosteroids (see Corticosteroids, [[Corticosteroids]])
      • Corticosteroids Decrease REM Sleep
      • Studies are Conflicting as to the Association of Delirium with Systemic Corticosteroids
        • Study of Delirium Risk Factors in Patients with Acute Lung Injury (Crit Care Med, 2014) [MEDLINE]: systemic corticosteroids were associated with an increased risk of delirium
        • Prospective Cohort Study of Risk Factors for Delirium in the ICU (Int Care Med Exp, 2015) [MEDLINE]: systemic corticosteroids were not associated with an increased risk of delirium
    • Opiates (see Opiates, [[Opiates]])
  • Use of Lines/Catheters
  • Use of Physical Restraints
    • Studies
      • Use of Physical Restraints During the ICU Stay May Increase the Risk of PTSD (Am J Crit Care, 2001) [MEDLINE]
      • Study of the Influence of Physical Restraints on Unplanned Extubation in Adult ICU Patients (Am J Crit Care, 2008) [MEDLINE]: an impaired level of consciousness on admission to the ICU and the presence of nosocomial infection increased the risk for unplanned extubation, even when physical restraints were used
      • Use of Physical Restraints is Associated with Sedative Use, Analgesic Use, Anti-Psychotic Drug Use, Agitation, Heavy Sedation, and Occurrence of an Adverse Event (Crit Care, 2014) [MEDLINE]: treatment characteristics predominantly predicted restraint use, as opposed to patient or hospital/ICU characteristics

Risk Factors for Intensive Care Unit-Associated Delirium (Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit; Critical Care Med, 2013) [MEDLINE]

  • Four Predominant Risk Factors for Intensive Care Unit-Associated Delirium (Grade B Evidence)
    • High Severity of Illness at Admission
    • History of Ethanol Abuse (see Ethanol, [[Ethanol]])
    • History of Hypertension (see Hypertension, [[Hypertension]])
    • Pre-Existing Dementia (see Dementia, [[Dementia]])
  • Coma is an Independent Risk factor for the Development of Intensive Care Unit-Associated Delirium (Grade B Evidence)
  • Medication Administration
    • In Mechanically Ventilated Patients, Dexmedetomidine is Associated with a Decreased Risk of Delirium, as Compared to Benzodiazepine Administration (Grade B Evidence)
    • Benzodiazepine Administration May Be Associated with an Increased Risk Factor for the Delirium in ICU Patients (Grade C Evidence)
    • Data are Unclear as the Association Between Opiate Administration and Risk of Delirium in ICU Patients (Grade B Evidence)
    • Data are Unclear as the Association Between Propofol Administration and Risk of Delirium in ICU Patients (Grade C Evidence)

Risk Factors for Delirium After Cardiac Surgery Requiring Cardiopulmonary Bypass (Crit Care, 2015) [MEDLINE]

  • Strong Evidence
    • Age
    • Cerebrovascular Disease
    • Duration of Mechanical Ventilation
    • History of Cognitive Impairment
    • History of Psychiatric Disease
    • Peri-Operative Blood Product Transfusion
    • Post-Operative Atrial Fibrillation
    • Risperidone Administration (see Risperidone, [[Risperidone]])
    • Type of Surgery
  • Moderate Evidence
    • Post-Operative Oxygen Saturation
    • Renal Insufficiency
  • No Evidence
    • Duration of Cardiopulmonary Bypass (see Cardiopulmonary Bypass, [[Cardiopulmonary Bypass]])
    • Education
    • Gender
    • History of Cardiac Disease or Congestive Heart Failure

Protective Factors Against Intensive Care Unit-Associated Delirium

  • Statin Use (see HMG-CoA Reductase Inhibitors, [[HMG-CoA Reductase Inhibitors]])
    • Study of Statin Use and CRP in Relation to ICU Delirium (Am J Respir Crit Care Med, 2014) [MEDLINE]: prospective cohort analysis (n = 470)
      • In Patients Previously on Statins Prior to ICU Admission, Statin Use the Night Prior was Associated with Decreased C-Reactive Protein (CRP) and Decreased Risk of ICU Delirium the Next Day

Etiology

Infection

Metabolic Disease

Neurologic Disease

Vascular

Withdrawal

Deficiency

Drug/Toxin

Other


Physiology

Mechanisms Contributing to the Development of Delirium in the Intensive Care Unit

Intensive Care Unit-Associated Delirium is Associated with Structural Changes in the Brain


Diagnosis

Delirium Scoring Scales

Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)

Intensive Care Delirium Screening Checklist (ICDSC)

Recommendations (Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit; Critical Care Med, 2013) [MEDLINE]


Clinical Manifestations

Neurologic Manifestations

Other Manifestations

Consequences of Intensive Care Unit-Associated Delirium (Especially in Mechanically Ventilated Patients)

Development of Long-Term Cognitive Impairment

Development of Post-Traumatic Stress Disorder (PTSD) (see Post-Traumatic Stress Disorder, [[Post-Traumatic Stress Disorder]])

Functional Decline/Disability

Higher Reintubation Rate

Increased Mortality Rate

Patient Removal of Urinary/Vascular Catheters

Prolonged ICU and Hospital Length of Stay

Self-Extubation


Prevention of Delirium

Based on Synopsis of the National Institute for Health and Clinical Excellence Guideline for Prevention of Delirium (Ann Intern Med, 2011) [MEDLINE]

Specific Prevention Measures

General Comments

Dexmedetomidine (Precedex) (see Dexmedetomidine, [[Dexmedetomidine]])

Early Mobilization in the Intensive Care Unit

Haloperidol (Haldol) (see Haloperidol, [[Haloperidol]])

Ketamine (see Ketamine, [[Ketamine]])

Ramelteon (see Ramelteon, [[Ramelteon]])

Reduction in Sleep Disruption in the Intensive Care Unit

Risperidone (Risperdal) (see Risperidone, [[Risperidone]])

Rivastigmine (see Rivastigmine, [[Rivastigmine]])

Systematic Reviews/Meta-Analyses Examining the Clinical Impact of Delirium Prevention Strategies

Impact of Delirium Prevention Interventions on Mortality Rate

Impact of Delirium Prevention Interventions in Hospitalized Non-ICU Patients

Recommendations (Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit; Critical Care Med, 2013) [MEDLINE]


Treatment of Delirium

General Management

Agents

General Comments

Dexmedetomidine (Precedex) (see Dexmedetomidine, [[Dexmedetomidine]])

Haloperidol (Haldol) (see Haloperidol, [[Haloperidol]])

Olanzapine (Zyprexa) (see Olanzapine, [[Olanzapine]])

Quetiapine (Seroquel) (see Quetiapine, [[Quetiapine]])

Risperidone (Risperdal) (see Risperidone, [[Risperidone]])

Valproic Acid (Depakote) (see Valproic Acid, [[Valproic Acid]])

Ziprasidone (Geodon, Zeldox) (see Ziprasidone, [[Ziprasidone]])

Recommendations (Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit; Critical Care Med, 2013) [MEDLINE]


References