Venturi Mask FiO2 — FRCA Primary MCQ
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Correct answer: E — Bernoulli/Venturi effect entraining a precise amount of room air
The Venturi mask uses the Bernoulli/Venturi principle: high-velocity oxygen through a narrow orifice creates low pressure entraining room air through side ports in a fixed ratio providing FiO2 24-60%. Total flow exceeds peak inspiratory flow ensuring accurate FiO2.
Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment