Post-op delirium

(formerly post-operative cognitive dysfunction)


Definition of delirium:

·         Organic cerebral syndrome

·         Aetiologically non-specific

·         Acute onset and fluctuating course

·         Disturbance in attention, awareness, cognition

·         Can be hyperactive, hypoactive or mixed




·      Old

·      Cognitive impairment

·      Hearing or vision impairment

·      Comorbidities

·      Poor functional status

·      Polypharmacy

General insults

·      Sleep deprivation

·      Malnutrition

·      Urinary retention

·      Constipation

Specific pathology

·      Hypoxaemia

·      Hypothermia

·      Dehydration

·      Electrolyte derangement

·      Infection

·      Renal impairment

Surgery and anaesthesia

·      Long duration

·      Hip fracture

·      Aorta


Post-op timeline:

Within 1/52

Post-op delirium

Within 1/12

Post-op neurocognitive disorder

After 1/12

Neurocognitive disorder

*Post-operative cognitive dysfunction is no longer a thing*


Intra-op prevention:

General management

·      Cause is surgery + anaesthesia, not anaesthesia alone

·      General and neuraxial are the same

·      Light sedation and deep sedation are the same

·      Blood pressure fluctuation is bad

Anaesthesia drugs

·      BIS <40 is bad

·      Propofol is probably better than the fluranes

·      Dexmedetomidine is good (load 0.5mcg/kg, infuse 0.2mcg/kg/h)

·      Ketamine is good at analgesic infusion rates

·      Benzodiazepines are bad

Other drugs

·      Dexamethasone is good (??)


Post-op prevention:

Drugs to give

·      Adequate analgesia

·      Dexmedetomidine infusion if in ICU

Drugs to avoid

·      Beer’s list

·      Multiple new medications

·      Tricyclic antidepressants (central anticholinergic)

·      Glucocorticoids

·      Benzodiazepines

·      Other sedative-hypnotics


*Use psychoactives as last resort in managing delirium*

*Start low, go slow*


·      Prompt diagnosis of complications e.g. UTI

·      Avoid hypovolaemia

·      Avoid electrolyte disturbance

·      Remove urinary catheter early

Nursing and allied health

Multi-disciplinary programme:

·      Regular screening for delirium

·      Orientation

·      Vision and hearing aids

·      Sleep hygiene

·      Early mobilization

·      Cognitive stimulation


*reduces cost*

*reduces institutionalization*



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