volume after the compensatory mechanisms of the infant brain have been
used. Cerebral edema peaks at 72-96 hours after injury and will slowly resorb
over a 7 day time period.
III. Intracranial Monitoring
“Treating TBI without knowing the ICP is like treating diabetes without
knowing the serum glucose” ~ PM Kochanek
Although prospective, randomized clinical trials are lacking, there is robust
evidence to support improved outcomes and decreased morbidity with patients
who undergo aggressive management and treatment for increased ICP. ICP
monitoring should be considered for any child with a GCS less than 8 [22].
Additionally, infants with open fontanelles should still be considered for ICP
monitoring. Cerebral perfusion pressure (CPP) is the difference between the
arterial inflow and venous outflow and is considered the transmural pressure
gradient that is ultimately the driving force required for supplying cerebral
metabolic needs. CPP is easily measured from ICP with the mathematical
difference between the mean arterial pressure and ICP. At a CPP of 10 mm
Hg, blood vessels collapse and blood flow ceases. Studies have shown a good
correlation between CPP and cerebral blood flow (CBF) in patients with intact
cerebral autoregulation [23]. CBF is defined as the velocity of blood through
the cerebral circulation. In normal adults, CBF is 50 to 55 mL/100 g of brain
tissue/min. In children, CBF may be much higher depending on their age. At 1
year of age, it approximates adult levels, but at 5 years of age, normal CBF is