Chairman’s Introduction

Abstract

Several major factors influence the relationship of pressure to volume within the intracranial space. Of major importance is the volume of the various intracranial compartments (brain tissue, intravascular blood, and CSF) at the time measurements are made to assess the volume-pressure relationship. For example, edema may expand the brain tissue compartment without increasing intracranial pressure (ICP) if the volume of CSF expressed from the intracranial space is equal to the volume of edema fluid, but the swelling may significantly alter the intracranial compliance and therefore the volume-pressure relationship. Compliance is determined by the volume and rate of displacement of brain tissue fluid, intravascular blood, and CSF. Since fluid cannot be displaced from the intracranial space instantaneously, the volume-pressure relationship is also affected by the rate of expansion of the mass or any new volume added to the intracranial space. As the mass expands within the intracranial space, brain tissue is displaced along a path of least resistance through the tentorial incisura and/or the foramen magnum. The volume of brain herniation will influence the volume-pressure relationship.