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Bain System FGF Requirement — FRCA Final MCQ

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ModerateAnaesthetic Equipment & SafetyBain System FGF RequirementFRCA Final

A Bain (coaxial Mapleson D) breathing system is being used for spontaneous ventilation. What fresh gas flow rate is required to prevent rebreathing?

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Correct answer: D — 2-3 times minute ventilation

Mapleson D (Bain): for spontaneous ventilation requires 2-3× minute ventilation FGF to prevent rebreathing (approximately 150-200 mL/kg/min). For controlled ventilation: 70-80 mL/kg/min is sufficient. The Mapleson D is most efficient for controlled ventilation.

Reference: RCOA – 2020 – Primary curriculum: Breathing systems