Cerebral perfusion pressure (CPP) plays a central role in neurocritical care and is crucial for maintaining adequate cerebral blood flow.
Definition
CPP is defined as the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP):
CPP = MAP – ICP
This relationship shows that CPP is influenced by both MAP and ICP.
Normal values
The normal CPP value in adults is above 50 mmHg[^2].
CPP optimization
Various approaches can be pursued to optimize CPP:
Increasing MAP: This can be achieved through fluid administration or medications that increase blood pressure. Increasing MAP leads to an elevated CPP, provided that ICP remains constant.
Lowering ICP: Intracranial pressure can be reduced pharmacologically, for example through sedation or Mannitol, or through surgical procedures such as decompressive hemicraniectomy. Lowering ICP has a positive effect on CPP by increasing the difference relative to MAP.
Clinical relevance in trauma
In patients with Traumatic brain injury, it has been shown that patients benefit more from reducing ICP than from increasing MAP to maintain cerebral perfusion[^1].