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Carotid baroreceptor reflex — FRCA Primary MCQ

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HardPhysiologyCarotid baroreceptor reflexFRCA Primary

A 74-year-old man has a sudden fall in blood pressure after induction. The ECG shows sinus bradycardia and the arterial waveform has low pulse pressure. Carotid sinus massage would worsen the problem by which reflex pathway?

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

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Correct answer: D — Chemoreceptor stimulation increasing sympathetic tone

Carotid sinus stretch increases baroreceptor firing through glossopharyngeal afferents, increasing vagal efferent activity and reducing sympathetic outflow. This worsens bradycardia and hypotension in a susceptible patient. Chemoreceptor responses are more relevant to hypoxaemia, hypercapnia and acidaemia. The pearl is that baroreflexes defend pressure but can be maladaptive when triggered inappropriately.

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