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Sevoflurane and Compound A — FRCA Primary MCQ

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HardPharmacologySevoflurane and Compound AFRCA Primary

A patient receiving sevoflurane in a low-flow circle system has fresh soda lime and stable inspired CO2. Which issue is most specifically associated with sevoflurane degradation in absorbent under low-flow conditions?

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Correct answer: C — Compound A formation

Sevoflurane can degrade in carbon dioxide absorbents to Compound A, particularly with low flows and certain absorbents. Malignant hyperthermia is a pharmacogenetic reaction to volatile agents and suxamethonium, but it is not a degradation product issue. Methaemoglobinaemia and cyanide release are not typical sevoflurane absorber concerns. The practical pearl is to follow manufacturer and machine guidance on low-flow use.

Reference: RCoA Primary FRCA Syllabus 2026; Peck, Hill & Williams Pharmacology for Anaesthesia