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Pregnancy respiratory physiology — FRCA Primary MCQ

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HardPhysiologyPregnancy respiratory physiologyFRCA Primary

A term pregnant patient desaturates quickly after induction despite adequate pre-oxygenation. Which combination best explains this?

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Correct answer: D — Reduced FRC and increased oxygen consumption

Pregnancy reduces functional residual capacity and increases oxygen consumption, shortening safe apnoea time. Minute ventilation rises in pregnancy rather than falls. Cardiac output increases, and the gravid uterus worsens supine respiratory mechanics. This physiology underpins rapid sequence induction planning in obstetric anaesthesia.

Reference: West Respiratory Physiology; Obstetric anaesthesia textbooks