Turbulent flow — FRCA Primary MCQ

Correct answer: D — Lower gas density reduces turbulent resistance

Lower density reduces turbulent resistance, which is why helium-oxygen mixtures may reduce work of breathing in turbulent flow. Dalton's law is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Poiseuille's law is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Venturi effect is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Henry's law 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