Post Operative Confusion

OVERVIEW

  • 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

Anaesthetic

  • 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

Surgical

  • 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

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

CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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