During prolonged sevoflurane anaesthesia with low fresh gas flows (<1 L/min), a nephrotoxic compound is generated by reaction of the agent with the CO2 absorbent. This compound is:

• A Trifluoroacetic acid
• B Carbon monoxide
• C Compound B (methanol derivative)
• D Compound A (fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether) ✓

Explanation

Sevoflurane reacts with strong alkalis (especially desiccated barium hydroxide lime and soda lime) to produce Compound A, a vinyl ether with dose-dependent nephrotoxicity in animal models. The risk increases with low fresh gas flows (higher absorbent contact), desiccated absorbent, and high temperatures. Carbon monoxide is produced by desflurane and isoflurane with desiccated absorbents, not sevoflurane. Trifluoroacetic acid is a hepatotoxic metabolite of halothane.

Reference: Morgan & Mikhail's Clinical Anesthesiology, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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