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

Pre-existing	· 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

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*

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 (??)

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
Medical	· 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