Post Operative Confusion
9/11/10
SP Notes
Part II Notes
- often multi-factorial
- not uncommon
- requires a systematic approach (history, review of notes, examination and review of investigation with simultaneous management)
RISK FACTORS
- increased age
- polypharmacy
- pre-existing confusion, delirium and dementia
- pre-existing electrolyte abnormalities
- previous brain dysfunction (CVA)
CAUSES
- drug induced: opioids, benzodiazepines, ketamine, anti-emetics, partial reversal, inhalational agents
- hypothermia
- electrolytes: hypoglycaemia
- pain
- respiratory failure: hypoxia, hypercarbia (find cause)
- cardiovascular instability: hypotension (cardiogenic, distributive, hypovolaemic, obstructive) ischaemia, bleeding and anaemia, heart failure
- neurological: ischaemia, seizures, cerebral oedema
- rare: alcohol withdrawal, MH, serotonin syndrome, NMS
- bleeding/anaemia
- perforation of viscus -> sepsis/SIRS
- procedure related risks: TURP syndrome
- sepsis
- distended bladder
INVESTIGATIONS
- as directed by likely causes, often requires:
- ABG
- U+E
- glucose
- FBC
- CXR
- ECG
Jeremy Fernando (2011)

MANAGEMENT
- treat cause!
Resuscitate
- may require airway protection if not rousable or risk of aspiration
- may require mechanical ventilation if in respiratory failure, O2 supplementation
- support circulation while finding cause – fluids/vasoactives/blood products
Electrolytes and Acid-base
- treat life threatening electrolytes abnormalities: hypoglycaemia -> glucose, hypo/hyperkalaemia
- access acid-base status
Specific Therapy
- opioid reversal: naloxone
- benzodiazepine reversal: flumazenil (cautious c/o seizure risk)
- residual neuromuscular blockade: neostigmine and atropine
Underlying Cause
- stop offending medication(s)
- dependent on cause
- disorientation common in dementia patients -> re-orientate, well lit environment, family support, small titrated doses of an antipsychotic
Jeremy Fernando (2011)