Chapter 54 - Intracranial pressure monitoring

Abstract

Publisher Summary This chapter describes methodology for intracranial pressure (ICP) monitoring. Intracranial cerebrospinal fluid (CSF) pressure results from the interaction of two systems. The CSF system has a constant inflow rate and an outflow absorption rate that is proportional to the height of the intracranial CSF pressure. This is a hydraulic system in which forces are equally distributed. When there is free communication within the craniospinal system and the patient is lying flat, the same pressure is recorded from the ventricle, cranial subarachnoid space, cisterna magna, and lumbar subarachnoid space provided that the same reference points are used. Under normal (equilibrium) conditions, ICPs measured outside the CSF space are a close approximation to CSF pressure, but this may not be so under changing conditions. The CSF system governs both the equilibrium pressure at which CSF inflow and outflow are matched and any change in CSF volume with respect to time. The brain tissue system determines the equilibrium CSF volume that corresponds to equilibrium pressure and the magnitude of changes in CSF pressure with respect to time.