An adult head injury patient is being managed on the intensive care unit. Current measurements show mean arterial pressure 95 mmHg and intracranial pressure 22 mmHg. Using standard targets for cerebral perfusion pressure in severe traumatic brain injury, the appropriate interpretation and action is:

• A CPP is 117 mmHg, reduce the mean arterial pressure with vasodilators
• B CPP is 73 mmHg, within target, no change required ✓
• C CPP is 22 mmHg, urgently raise mean arterial pressure with noradrenaline
• D CPP cannot be calculated without jugular venous oximetry

Explanation

Cerebral perfusion pressure equals mean arterial pressure minus intracranial pressure: here 95 minus 22 equals 73 mmHg, which lies within the recommended target range of 60 to 70 mmHg or slightly above, so current therapy should continue. Option A misapplies the formula, and option C confuses the intracranial pressure value with the perfusion pressure. Jugular venous oximetry informs oxygen extraction monitoring but is not required to calculate CPP, which needs only two bedside numbers.

Reference: Sabiston Textbook of Surgery, 21st ed.

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Written and medically reviewed by the StethoPrep medical team.