Cerebral perfusion pressure — FRCA Primary MCQ

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ModeratePhysiologyCerebral perfusion pressureFRCA Primary

A head-injured patient has MAP 82 mmHg and intracranial pressure 28 mmHg during transfer. What is the most appropriate cerebral perfusion pressure?

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

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Correct answer: C — 54 mmHg

Cerebral perfusion pressure is calculated as MAP minus intracranial pressure, so 82 minus 28 gives 54 mmHg. Using MAP alone ignores the opposing pressure from the cranial vault. Adding MAP and ICP is physiologically incorrect. CPP is a pressure gradient, and both hypotension and raised ICP can critically reduce it.

Reference: Ganong Review of Medical Physiology; Neuroanaesthesia textbooks