In the context of moderate-severe TBI, what is the purpose of maintaining a CPP target?

• A. To ensure adequate cerebral blood flow and oxygen delivery to the brain
• B. To optimize systemic vascular resistance
• C. To minimize heart rate
• D. To maximize CSF production

Answer: (C)

The purpose of a CPP target is to ensure adequate cerebral blood flow and oxygen delivery to the brain when intracranial pressure is elevated after a moderate to severe TBI. CPP represents the driving pressure for blood entering the brain, calculated roughly as mean arterial pressure minus intracranial pressure. If CPP falls too low, cerebral blood flow decreases and brain tissue becomes ischemic, fueling secondary injury. Therefore, the goal is to keep CPP in a range that maintains sufficient cerebral perfusion, often around 60–70 mmHg, individualized to the patient. This is achieved by supporting MAP and actively managing ICP through fluid and vasopressor strategies, osmotic therapies, or drainage as appropriate. The other options don’t address perfusion of brain tissue: systemic vascular resistance, heart rate, and CSF production aren’t the main levers for ensuring adequate brain blood flow and oxygen delivery.