CICM SAQ 2011.2 Q1

Question

List the complications and their likely underlying mechanisms specifically related to cardiopulmonary bypass that may be seen in the Intensive Care Unit following cardiac surgery.

Answer

Answer and interpretation

Respiratory complications

  • Left lower lobe collapse (poor re-inflation post bypass, phrenic nerve injury)
  • Increased pulmonary vascular resistance (protamine)
  • Acute lung injury (SIRS)

Cardiovascular complications

  • Myocardial stunning or infarction (inadequate myocardial protection)
  • Coronary graft ischaemia (air embolism)
  • Right ventricular dysfunction (pulmonary hypertension related to protamine)
  • Hypoperfusion and end-organ ischaemia related to non-pulsatile flow and/or air/atheroma embolism

Neurological complications

  • Cerebrovascular events, watershed infarcts, neurocognitive dysfunction (low flow, thromboembolism)
  • Phrenic nerve palsy (use of cold cardioplegia ‘slush’)

Renal complications

  • Dysfunction related to ischaemia and SIRS

Gastro-intestinal complications

  • Splanchnic ischaemia (low flow, thromboembolism)
  • Hepatitic dysfunction, acalculous / gangrenous cholecystitis, pancreatitis (hypoperfusion, SIRS)

Haematological complications

  • Coagulopathy (effects of hypothermia and dilutional coagulopathy, residual heparinisation, activation of coagulation cascade during bypass)
  • Anaemia (haemodilution, blood loss in the circuit)
  • Platelet dysfunction (bypass circuit)
  • Haemolysis (bypass circuit)

Metabolic complications

  • Hypothermia (intra-operative cooling and delayed re-warming) Insulin resistance and hyperglycaemia (hypothermia)
  • Electrolyte abnormalities (haemodilution, post-pump diuresis)

Immune-mediated complications

  • Activation of coagulation cascade (blood contact with non-biological surfaces and blood-gas interface)
  • SIRS (leucocyte and complement activation, cytokine release and expression of adhesion molecules stimulated by contact with bypass circuit)
  • Allergic reactions to protamine
Exams LITFL ACEM 700

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CICM

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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