Hypoxic mixture prevention — FRCA Primary MCQ

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HardPhysicsHypoxic mixture preventionFRCA Primary

The machine links oxygen and nitrous oxide flows to reduce hypoxic mixture risk. What is the most important safety consideration?

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Correct answer: A — Hypoxic guard

Hypoxic guards reduce the chance of hypoxic flowmeter mixtures. Sampling tube transit delay is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Circle system exhausted absorbent is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Top of the bobbin gives calibrated flow is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Airway laser fire risk 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