Intracranial pressure monitoring

Alternative names:

ICP monitoring

Normal values:

Normally, the ICP ranges from 1 to 15 mm Hg.

Note: mm Hg = millimeters of mercury

What abnormal results mean:

In an infant whose fontanelles are still open, increased ICP results in stretching of the fontanelles, enlargement of the skull, and compression of the brain. In a child or adult whose skull is a closed cavity of finite volume, increased ICP causes compression of the brain.

The total volume of the skull is normally 80% brain, 10% CSF and 10% blood. This volume is in a dynamic equilibrium, if the volume of one increases the volume of the others must decrease by an equal amount. Increased ICP is usually caused by an increase in CSF. If the volume of CSF increases, then the volume of the others must decrease. A majority of this volume change will occur in the brain matter itself. This pressure can cause brain damage and death if left unchecked.