Soda lime heat — FRCA Primary MCQ

Correct answer: B — Exothermic carbon dioxide absorption

Carbon dioxide absorption by soda lime is exothermic and may warm the absorber canister. Top of the bobbin gives calibrated flow is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Hypoxic guard is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Pin index system is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Mapleson D is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. In Primary FRCA physics and measurement, the safest answer is the one that follows the underlying physical principle and the limitations of the device.

Reference: Davis and Kenny Basic Physics and Measurement in Anaesthesia; RCoA Primary FRCA syllabus