blood pressure may not be interpreted to signify adequate cardiac output or
perfusion just as normal urine output may not equate with normal renal function.
II. Neurologic Monitoring
A. ICP Monitoring
Intracranial pressure (ICP) monitoring is indicated in patients at risk of or
experiencing intracranial hypertension (ICH) from causes such as trauma,
spontaneous intracranial hemorrhage, or hydrocephalus. Normal horizontal
position ICP in healthy adults is 7-15mmHg and 5-10mmHg in children. An ICP
40 for 4 hours or more is considered unsurvivable. ICP is highly variable and a
30 - minute average is utilized to follow Mean ICP. Measuring ICP allows the
intensivist to calculate cerebral perfusion pressure (CPP=MAP-ICP). Goal CPP
for an adult or teenage child is 60-70mmHg, for a school aged child is 40-65, and
for children under two years old is ill-defined. Multiple modalities are available
for ICP monitoring. The choice of modality weighs the risks (infection,
hemorrhage, CSF overdrainage) vs. benefit (reliability of measurement and
ability to therapeutically drain CSF).
A ventriculostomy is a catheter that is placed into the lateral ventricle and
is considered the gold-standard for measuring ICP. In addition to monitoring, this
modality has the benefit of therapeutic drainage of CSF to decrease ICP –
although excess drainage can lead to emptying of the ventricular system and
accumulation of subdural hematoma. The risk of infection (~5%) starts to
increase after five days and is not improved with prophylactic antibiotics.