Bain Circuit Mapleson D — FRCA Primary MCQ

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HardPhysics & Clinical MeasurementBain Circuit Mapleson DFRCA Primary

The Bain breathing system is a coaxial modification of which Mapleson circuit?

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Correct answer: B — Mapleson D

The best answer is “Mapleson D”. The Bain system is a coaxial Mapleson D circuit: fresh gas travels through the inner tube and expired gas through the outer reservoir tube. Its efficiency depends on the mode of ventilation and fresh-gas flow. Other Mapleson arrangements have different fresh-gas, reservoir-bag and valve positions.

Reference: RCoA, Primary FRCA Syllabus: https://rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf