Delirium in the ICU

Delirium in the ICU: 

Delirium in the ICU from witness to criminal Dr. Andrew Ferguson MEd FRCA FCARCSI DIBICM FCCP

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“The subject of delirium is generally looked upon by the practical physician as one of the most obscure in the chain of morbid phenomena he has to deal with; whilst the frequency of its occurrence under various conditions of the system renders the affection not a little familiar to his eye” Gallway MB (1838). Nature and treatment of delirium. Lond Med Gazette 1: 46–49.

Overview: 

Overview What is delirium ? How is it categorised? Why does it matter? Why does it happen? How do we diagnose/monitor it? How do we prevent and treat it? What does it mean for our patients?

What is Delirium?: 

What is Delirium? An acute confusional state with Fluctuating mental status Disordered attention Disorganised thinking OR altered consciousness DSM IV definition : “a disturbance of consciousness with inattention accompanied by a change in cognition or perceptual disturbance that develops over a short period (hours to days) and fluctuates with time” Synonyms : ICU psychosis, septic encephalopathy, ICU syndrome, acute brain failure, acute confusional state

How is Delirium Categorised?: 

How is Delirium Categorised? Hyperactive Hypoactive Mixed 1.6% of cases, “ ICU psychosis ”, agitation, restlessness, “picking”, emotional lability 54.1% % of cases 43.5% of cases, “ encephalopathy ”, often unrecognised, withdrawal, flat affect, apathy, lethargy, decreased responsiveness, may be misdiagnosed as depression

Why does delirium matter?: 

Why does delirium matter? Increased reintubation risk (OR=3) Increased ICU & hospital stay * (up to 10 days extra) Each day in delirium increases risk of longer stay by 20% Increased mortality in ICU & out to 6 months** (OR=3) Each day spent in delirium increases risk of death by 10% Increased ICU & hospital costs *** 10-24% risk of long-term cognitive impairment Increased dementia risk Reduced functional status at 3 & 6 months * Ely et al, Intensive Care Med 2001; 27: 1892-1900 ** Ely et al, JAMA 2004; 291: 1753-62 *** Milbrandt et al, CCM 2004; 32: 955-62

Why does delirium happen?: 

Why does delirium happen? Higher cortical dysfunction (on functional neuroimaging) Pre-frontal cortex, non-dominant posterior parietal regions, anterior thalamus, basal ganglia, temporal-occipital cortex Neurotransmitter dysfunction Reduced acetylcholine levels – blockade or deficiency Endogenous anticholinergic substances Opiates/hypoxia/inflammation Serotonin fluctuation Dopamine excess Glutamate excess (2 o to IFN- g , LPS, hypoxia, hypoglycaemia) Predisposition (baseline vulnerability) Precipitants (clinical, iatrogenic, organisational risk factors)

Why does delirium happen?: 

Why does delirium happen? Serotonin Acetylcholine Dopamine Opioids & benzo’s 2 o brain infection Decreased cerebral metabolism 1 o intracranial disease Systemic disease Hypoxia Metabolic derangement Withdrawal syndromes Toxins

Risk factors for delirium: 

Risk factors for delirium Van Rompaey Intensive and Critical Care Nursing 2008; 24: 98—107

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Age Severity Benzo’s Pun & Ely, Chest 2007; 132: 624–636 Pandharipande et al, Anesthesiology 2006; 104: 21-26

DELIRIUM(S) - causes: 

DELIRIUM(S) - causes D Drugs, dementia E Eyes & ears (poor vision and hearing) L Low O 2 states (CHF, COPD, ARDS, MI, PE) I Infection R Retention (urine and stool) I Ictal states U Underhydration/undernutrition M Metabolic upset (S) Subdural, sleep deprivation

I WATCH DEATH: 

I WATCH DEATH I Infection W Withdrawal (alcohol, sedatives, barbiturates etc.) A Acute metabolic (acidosis, alkalosis, electrolytes) T Trauma (closed head injury, haematoma etc.) C CNS pathology (seizures, stroke, encephalitis) H Hypoxia D Deficiencies (thiamine, niacin, B12, folate) E Endocrinopathies (thyroid, glucose, adrenal) A Acute vascular (hypertensive crisis, arrhythmia) T Toxins/drugs H Heavy metals

Diagnosis & monitoring: 

Diagnosis & monitoring Level of consciousness Content of consciousness

Diagnosis & monitoring: 

Diagnosis & monitoring Intensive Care Delirium Screening Checklist (ICDSC) 8 items based on data from preceeding 24 hours Score > 4 items = positive for delirium Sensitivity 99%, specificity 64%, inter-observer reliability 94% Simple Confusion Assessment Method for ICU (CAM-ICU) 4 features Altered or fluctuating mental status compared to baseline Inattention (Attention Screening Examination – ASE, visual or auditory recollection of letter or images) Disorganised thinking – 4 Y/N questions + hold up 2 fingers on each hand Altered consciousness – sedation scale e.g. RASS Delirium = 1 AND 2 plus 3 OR 4

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ICDSC

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CAM-ICU

Treating delirium: 

Treating delirium Non-pharmacological (most studied outside ICU) Up to 40% risk reduction achieved Repeated reorientation of patients Early mobilisation Visual and hearing aids (and wax removal!) Early catheter, line etc. removal Minimise restraints and sedatives

Treating delirium - haloperidol: 

Treating delirium - haloperidol Typical antipsychotic 2-5 mg iv/po q6H (reduce in elderly) Adverse effects – extrapyramidal, prolonged QTc, torsades (3.8%), neuroleptic malignant syndrome More effective than lorazepam ? mortality reduction in ventilated ICU patients Dopamine blockade + disinhibition of ACh Anti-inflammatory effects Girard & Ely, Handbook of Clinical Neurology 2008; 90: chapter 3

Treating delirium – atypical antipsychotics: 

Treating delirium – atypical antipsychotics Olanzepine, quetiapine, risperidone Alter multiple neurotransmitters including DA, NA, serotonin, ACh, histamine Suggestion of decreased extrapyramidal side-effects compared to haloperidol As effective as haloperidol Girard & Ely , Handbook of Clinical Neurology 2008; 90: chapter 3 Skrobik YK, Bergeron N, Dumont M et al . (2004). Olanzapine vs haloperidol: treating delirium in a critical care set- ting. Intensive Care Med 30: 444–449.107: 341–351. Han CS, Kim YK (2004). A double-blind trial of risperidone and haloperidol for the treatment of delirium. Psychosomatics 45: 297–301 Breitbart W, Marotta R, Platt M et al. (1996). A double- blind trial of haloperidol, chlorpromazine, and lorazepam in the treatment of delirium in hospitalized AIDS patients. Am J Psychiatry 153: 231–237.

Internet Resources: 

Internet Resources www.icudelirium.org