Neuroscience Clerkship

IMPORTANCE AND INDICATIONS FOR INTRACRANIAL PRESSURE MONITORING

In certain clinical situations, monitoring of intracranial pressure (ICP) is indicated. Unrecognized increased ICP leads to decreased cerebral perfusion pressure, brain ischemia, herniation and death. Elevations of ICP may precede clinical deterioration and therefore ICP monitoring may allow earlier interventions to prevent clinical deterioration.

Indications for ICP Monitoring

• Head injury (indications: GCS <8 with an abnormal head CT (e.g., hematoma, contusion, edema) or GCS <8 and a normal CT scan but with 2or more of the following: hypotension on admission; age > 40; motor posturing)

• Postoperative Craniotomy

• Reye’s Syndrome

• Brain swelling of unknown origin

Note: ICP monitoring is NOT useful for hypoxia (i.e., ischemic stroke, drowning, strangulation or post-cardiac arrest)

ICP Monitoring Sites

• Epidural (disadvantage: imperfect correlation with the intradural pressure)

• Subdural (disadvantages: infections are serious, tubes may clog)

• Intraparenchymal (typically a fiberotic catheter; advantages: ease of insertion and replacement, true brain pressure)

• Intraventricular (advantages: very accurate ICP, can withdraw fluid to lower the pressure; disadvantages: may be difficult to insert if ventricles small or displaced)