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Adrenaline Cardiac Sensitisation — FRCA Final MCQ

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ModerateGeneral AnaesthesiaAdrenaline Cardiac SensitisationFRCA Final

A 35-year-old woman (ASA I, 60 kg) is undergoing breast augmentation as a day case. She receives propofol, fentanyl, and an LMA. The surgeon uses tumescent local anaesthetic solution containing adrenaline 1:200000. Towards the end of the procedure, the patient develops ventricular bigeminy on the ECG. What is the most likely cause?

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Correct answer: D — Air embolism

Adrenaline absorbed systemically from large volumes of tumescent local anaesthetic solution can cause cardiac arrhythmias including ventricular bigeminy, PVCs, and potentially VT/VF. The risk is increased with volatile agents (especially halothane and to a lesser extent sevoflurane/desflurane), which sensitise the myocardium to catecholamines. Under TIVA with propofol, the risk is lower but not zero. Management: inform the surgeon to stop infiltrating, ensure adequate anaesthetic depth, and treat the arrhythmia (amiodarone if haemodynamically significant). The maximum recommended dose of adrenaline with halothane was 2 mcg/kg/10 min.

Reference: RCOA – 2023 – Final FRCA curriculum: drug interactions; BNF – 2025 – Adrenaline interactions