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OPCAB Haemodynamic Instability — FRCA Final MCQ

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ModerateCardiothoracic AnaesthesiaOPCAB Haemodynamic InstabilityFRCA Final

A 60-year-old man with coronary artery disease is undergoing off-pump coronary artery bypass (OPCAB) surgery. The surgeon lifts the heart to access the posterior descending artery. The patient develops acute haemodynamic instability with a drop in MAP to 45 mmHg. What is the most likely cause?

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Correct answer: C — Impaired venous return from cardiac displacement

During off-pump CABG, surgical displacement of the heart to access posterior and lateral vessels causes significant reduction in venous return and cardiac output. Lifting and rotating the heart compresses the right ventricle and obstructs venous inflow. Management: communicate with the surgeon (they may need to briefly reposition the heart), Trendelenburg position, fluid bolus, and vasopressor support. The use of deep pericardial sutures and cardiac stabilising devices can mitigate this effect. The anaesthetist must be prepared for rapid haemodynamic changes during these manoeuvres.

Reference: RCOA – 2023 – Cardiothoracic anaesthesia module; Chassot PG – 2004 – Off-pump CABG anaesthesia