Written by Mat Holland:

Delirium has been defined as “an acute, reversible organic mental syndrome with disorders of attention and cognitive function, increased or decreased psychomotor activity and a disordered sleep-wake cycle.”

Delirium is commonly seen in critically ill patients (up to 80% of patients) and is associated with increased length of stay, increased medical complications and poor outcomes including increased mortality at six months.

In addition there is growing evidence suggesting a link between delirium on intensive care and long term cognitive impairment.

Delirium can be divided into three subtypes: Hyperactive (patients are agitated, paranoid), Hypoactive (patients are withdrawn, quiet, paranoid), or mixed.

The keys to quality care in delirium management are prevention, recognition and diagnosis and treatment.


It is important to recognise patients that are at risk of developing delirium, as well as likely factors that may precipitate delirium in at risk patients.

Predisposing factors:

Preadmission factors:Drugs:Coexisting medical conditions:
Age >65
Male sex
Cognitive impairment, dementia
History of previous delirium
Poor mobility, falls, dependent of activities of daily living
Sensory impairment, blind or deaf
Dehydrated or malnourished
On multiple psychoactive drugs
Alcohol abuse
Severe illness
Multiple coexisting conditions
Chronic renal or hepatic disease
Previous cerebrovascular disease
Neurological disease
Metabolic derangements
Trauma or fractures
Terminal illness
HIV infection

Precipitating factors:

Drugs:Primary neurological diseases:Intercurrent illness:
Sedative hypnotics
Anticholinergic drugs
Alcohol or drug withdrawl
Stroke, particularly non-dominant hemisphere
Intracranial bleeding
Meningitis or encephalitis
Iatrogenic complications
Severe acute illness
Fever or hypothermia
Poor nutritional status
Low serum albumin
Metabolic derangements
Prolonged sleep deprivation
Orthopaedic surgery
Cardiac surgery
Prolonged cardiopulmonary bypass
Admission to intensive care
Use of physical restraints
Use of bladder catheter
Emotional stress

Prevention interventions:

A delirium “bundle” has been proposed in an attempt to decrease the incidence of delirium in patients in hospital.

1) Within 24 hours of admission, assess people at risk for clinical factors contributing to delirium and document this in the care plan.

2) Address cognitive impairment and/or disorientation by:

  • Introduction with name, time and place verbally and regularly.
  • Providing appropriate lighting and clear signage; a clock (consider providing a 24-hour clock in critical care) and a calendar should also be easily visible to the person at risk.
  • Talking to the person to re-orientate them by explaining where they are, who they are, and what your role is.
  • Introducing cognitively stimulating activities (for example, reminiscence).
  • Facilitating regular visits from family and friends – see visiting policy.

3) Ensure patient is adequately hydrated.

4) Address constipation with daily assessment and treat with laxatives (stimulant eg. senna +/- stool softener eg.docusate) +/- suppositories / enemata.

5) Assess for hypoxia and optimise oxygen saturations.

6) Assess for any evidence of infection, and treat if infection suspected.

Infection prevention is extremely important in the critically ill:

Prevention of ventilator associated pneumonia bundle:

  • Elevation of the head of the bed to 30-45 degrees
  • Sedation holding
  • Deep vein thrombosis prophylaxis
  • Gastric ulcer prophylaxis
  • Appropriate humidification of inspired gas
  • Appropriate tubing management
  • Suctioning of respiratory secretions (including use of gloves and decontaminating hands before and after the procedure)
  • Chlorhexidine gel for mouth care.

Prevention of line infection:

  • Appropriate and aseptic line insertion
  • Hand hygiene
  • Daily inspection
  • Dry adherent dressing
  • Aseptic catheter access as per protocol
  • Administration set replacement
  • Daily assessment for line removal
  • No routine catheter replacement

7) Address immobility through the following actions:

Encourage people to:
  • mobilise soon after surgery
  • walk (provide appropriate walking aids if needed)

• Encourage all people, including those unable to walk, to carry out active range-of-motion exercises. If patient unable to mobilise reposition patients as per protocol unless contraindicated.

8) Address pain by:

  • Assessing for pain
  • Looking for non-verbal signs of pain and use visual aid for pain assessment in patients with communication difficulties (for example, people with learning difficulties or dementia, or people on a ventilator or who have a tracheostomy.)
  • Starting and reviewing appropriate pain management in any person in whom pain is identified or suspected.

9) Daily medication review, stopping inappropriate medications

10) Address poor nutrition

  • Early enteral nutrition
  • Ensure those patients with dentures have their dentures and that they fit properly.

11) Address sensory impairment by:

  • Resolving any reversible cause of the impairment, such as impacted ear wax
  • Ensuring hearing and visual aids are available to and used by people who need them, and that they are in good working order.

12) Promote good sleep patterns and sleep hygiene by:

  • Avoiding nursing or medical procedures during sleeping hours, if possible.
  • Scheduling medication rounds to avoid disturbing sleep.
  • Reducing noise and extraneous lighting to a minimum during sleep periods.
  • If sleep deprivation a problem consider Zolpidem (5-10mg) or zopiclone (3.75-7.5mg). Do not use benzodiazepines for sleep promotion, unless the patient is taking them chronically, as they do not promote REM sleep.

Delirium prevention bundle
1) Assess risk of delirium in first 24 hours of admission
2) Address cognitive impairment and/or disorientation
3) Ensure patient is adequately hydrated
4) Address constipation
5) Assess and treat hypoxia
6) Assess for and treat infection
7) Early mobilisation
8) Adequate analgesia
9) Daily medication review
10) Adequate nutrition
11) Address sensory impairment problems
12) Promote good sleep patterns and sleep hygiene


Diagnosis of delirium requires the detection of acute or fluctuating mental status changes, with inattention and disorganised thinking or altered level of consciousness. A screening tool called the CAM-ICU (confusion assessment method – ICU) can be used to screen patients at the bedside.

Patients should be screened daily for delirium and have the result documented on the chart.

Once the diagnosis has been made this should be formally documented in the notes and treatment established.

CAM-ICU Delirium assessment method


Altered mental status
Has the patient shown any sign of being other than completely “themselves”?
Ask the patient to squeeze your hand. They will need to be responsive to verbal stimulation and keep their eyes open.
Ask the patient to correctly identify the letter ‘A’ in 10 letter sequence by squeezing only when they hear the letter ‘A’. Suggested Sequence:
They are allowed 2 mistakes - squeezing on a non-A, not squeezing on a A. More than 2 mistakes (however many it does not matter) is inattention.
If they pass the inattention test they are not delirious, the test is now complete.
More than 2 mistakes proceed to look for disorganized thinking or decreased level of consciousness.
Disorganised thinking &/or Reduced level of consciousness
5 elements - 4 simple yes/no questions, one simple command.
Use Set A or Set B
Set A:
Will a stone float on water?
Are there fish in the sea?
Does 1 pound weigh more than 2?
Do you use a hammer to hit a nail?
Set B:
Will a leaf float on water?
Are there elephants in the sea?
Does 2 pounds weigh more than 1?
Do you use a saw to hit a nail?
Ask the patient to
“raise 2 fingers with one hand” and then to “do the same with the other hand” (do not instruct the patient to “raise 2 fingers” a second time, but instead instruct them to “do the same with the other hand”) .
They are allowed one mistake - one question wrong or unable to do the command. Two mistakes means disorganized thinking. The patient is CAM-ICU positive.

In short:

Inattention plus altered conscious level equals delirium.
Inattention plus disorganised thinking equals delirium.
Inattention plus altered conscious level plus disorganised thinking equals delirium.


Initial management:

Patients diagnosed with delirium should be screened for possible causes and treated appropriately.

Ensure effective communication and reorientation as well as reassurance (for example explaining where the patient is who they are and what your role is, as well as repeating this as often as is required. Consider involving family and carers to help with this.

Delirium once diagnosed, should be treated pharmacologically if it is:

  • Persistent,
  • Delays the patient’s progress e,g, extubation, mobilisation, or
  • Hyperactive and distressing.

Haloperidol, on the current limited evidence available, is the drug of choice in all available guidelines.

Hypoactive delirium:

Haloperidol 1.25 mg qds and review after 24 hours.

Hyperactive delirium:

First line treatment – non-pharmacological:
Use verbal or non-verbal techniques to de-escalate the situation.

Second line treatment – pharmacological:
If verbal or non-verbal de-escalation techniques are ineffective, and the patient is considered a risk to themselves or others, pharmacological techniques are required.

1) Haloperidol is the first choice anti-psychotic drug for hyperactive delirium.

Haloperidol recommended starting dose 2.5 – 5 mg iv
Lower initial doses should be started in the elderly, higher doses in severely agitated patients.
If the patient remains unmanageable after 20-30 mins after an intravenous dose (and is not exhibiting any adverse side effects), then the haloperidol dose should be doubled, and the cycle repeated until the patient is manageable.

ie. If despite 5 mg haloperidiol there is no improvement of the hyperactive delirium after 20-30 mins 10 mg should be given. (PRN midazolam may be required as a rescue therapy between doses to ensure patient and staff safety) If after a further 20-30 mins the patient with hyperactive delirium is still uncontrollable, or has required more than one rescue dose of midazolam, repeat the 10 mg haloperidol, and continue until the risk from the patients hyperactive delirium is controlled.

Once control has been achieved a regular dose can be prescribed 4-6 hourly, either enterally or iv, and the dose should be weaned off over several days.

Adverse effects:
QT prolongation on the ECG. If the QT c >450 ms, or increased by >25% from prev ECGs, then the dose of haloperidol should be reduced or discontinued.

Acute dystonic reactions / extra-pyramidal side effects. If the patient demonstrates an acute dystonic reaction, (intermittent, spasmodic or sustained involuntary contractions of muscles in face, neck, trunk, pelvis or extremities) then treatment with iv. Procyclidine 5-10mg iv. Usually produces relief after 5-10 mins. Procyclidine can also be used for extra-pyramidal side-effects.

No maximum daily dose for haloperidol has been established, and continuous infusions of haloperidol at 5-10mg /hr have been successfully used, but these doses should be used with caution. Any patient requiring a cumulative dose of greater than 35 mg in 24 hours should be discussed with the duty consultant.

2) Clonidine infusion is useful in controlling agitation and delirium in patients that are withdrawing from alcohol, opiates etc.

Clonidine, as an infusion, is the second line treatment in hyperactive delirium.

750mcg in 50 ml (15mcg/ml) starting at 1mcg/kg/hr (4.6ml/hr in 70 kg pt) up to 4mcg/kg/hr (18.6ml/hr in 70 kg pt.)

Adverse effects: Hypotension and bradycardia, decreased conscious level.

In hyperactive delirium that is resistant to high doses of haloperidol (+/- clonidine), where the patient is deemed to be a risk to themselves or their carers then PRN midazolam (or propofol in intubated patients) should be considered.

If delirium does not resolve it is important to re-evaluate for underlying causes and to follow up and assess for possible dementia.


United Kingdom Clinical Pharmacy association (UKCPA): Detection, prevention and treatment of delirium in critically ill patients 2006

Girard T, Pandharipande P, Ely EW. Delirium in the intensive care unit. Critical Care 2008, 12(Suppl 3):S3

Jörg Martin et al. Evidence and consensus-based German guidelines for the management of analgesia, sedation and delirium in intensive care – short version. Ger Med Sci. 2010; 8: Doc02