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
Examination Library
CICM
Chris is an Intensivist and ECMO specialist at The Alfred ICU, where he is Deputy Director (Education). He is a Clinical Adjunct Associate Professor at Monash University, the Lead for the Clinician Educator Incubator programme, and a CICM First Part Examiner.
He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives. He was one of the founders of the FOAM movement (Free Open-Access Medical education) has been recognised for his contributions to education with awards from ANZICS, ANZAHPE, and ACEM.
His one great achievement is being the father of three amazing children.
On Bluesky, he is @precordialthump.bsky.social and on the site that Elon has screwed up, he is @precordialthump.
| INTENSIVE | RAGE | Resuscitology | SMACC