A patient has BP 120/60 and ICP 24; CPP calculation indicates

• A. Impaired brain blood flow.
• B. Normal intracranial pressure (ICP).
• C. High blood flow to the brain.
• D. Adequate cerebral perfusion.

Answer: (D)

Cerebral perfusion pressure (CPP) reflects the balance between the pressure driving blood into the brain and the pressure resisting it inside the skull. CPP = mean arterial pressure (MAP) minus intracranial pressure (ICP). To estimate MAP from a BP of 120/60, use MAP ≈ (SBP + 2×DBP)/3 = (120 + 120)/3 = 80 mmHg. With an ICP of 24, CPP = 80 − 24 = 56 mmHg. A CPP in the roughly 50–70 mmHg range is generally considered adequate to maintain cerebral perfusion, with many clinicians aiming for around 60 mmHg or higher. Therefore, despite the elevated ICP, cerebral blood flow is still being perfused adequately at this CPP level. If CPP were much lower (e.g., below about 40–50 mmHg), perfusion would be impaired; if CPP were much higher, there could be a risk of hyperemia or edema.