The intracranial vault is a closed compartment composed of brain tissue (80-85% of volume), blood and CSF. If volume is added, either from cerebral edema or a mass lesion (hematoma), ICP will increase, the Monro-Kellie doctrine. Initially, in compensation, there is egress of venous blood and CSF, but as more volume is added this compensation fails and ICP will increase exponentially. Normal ICP is < 10. Elevated ICP (> 20) is an established predictor of mortality and severe disability. One study showed that patients whose ICP remains < 20 have a 94% survival, which decreases to 59% in those with ICP > 20. The literature suggests an upper limit for ICP of 20 in adolescents and adults, 18 in children and 15 in infants. Cerebral perfusion pressure (CPP) is the difference between ICP and mean arterial pressure (MAP), i.e. CPP = MAP - ICP. As ICP increases, CPP falls, leading to decreased cerebral blood flow with resultant brain ischemia and hypoxia. "Severe" Pages: Previous 1 2 3 4 5 6 Next