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Dynamic airway compression in emphysema — FRCA Primary MCQ

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HardPhysiologyDynamic airway compression in emphysemaFRCA Primary

A 64-year-old man with emphysema has FEV1/FVC 0.48, increased total lung capacity and reduced gas transfer. Which physiological change best explains his increased work of breathing during expiration?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: A — High lung elastic recoil causing alveolar collapse

Emphysema destroys alveolar attachments, reducing radial traction and causing dynamic airway compression during expiration. Elastic recoil is reduced, not increased. Surfactant deficiency would reduce compliance, whereas emphysema often increases compliance. The clinical pearl is that pursed-lip breathing helps by increasing airway pressure and reducing collapse.

Reference: RCoA Primary FRCA Syllabus 2026; Ganong's Review of Medical Physiology; West's Respiratory Physiology