Delirium in the ICU

from witness to criminal

Dr. Andrew Ferguson MEd FRCA FCARCSI DIBICM FCCP

“ 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

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?

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? 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?

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?

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-  , LPS, hypoxia, hypoglycaemia)

Predisposition (baseline vulnerability)

Precipitants (clinical, iatrogenic, organisational risk factors)

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 Van Rompaey Intensive and Critical Care Nursing 2008; 24: 98—107

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

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 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 Level of consciousness Content of consciousness

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

ICDSC

CAM-ICU

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

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

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.

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