MODELING CHANGES OF THE CEREBRAL VASCULATURE INDUCED BY VARIATIONS OF [PCO.sub.2].
MODELING CHANGES OF THE CEREBRAL VASCULATURE INDUCED BY VARIATIONS
OF [PCO.sub.2]. Richard Pasley, Chunzhi Wang, Charles W. Leffler, and
Michael L. Daley, The University of Memphis, Memphis, Tennessee (RP, CW,
MLD), and The University of Tennessee, Memphis, Memphis, Tennessee
(CWL). Clinical recordings of intracranial pressure (ICP) and arterial
blood pressure (ABP) of patients with brain injury vary. For one
pathophysiologic state, the pressure recordings are dissimilar, while in
another they are similar. The purpose of this study was to develop a
model that describes the changes observed in coefficients of correlation
readings. The model assumes compression of the cerebral capillary bed by
transmission of changes of intrathoracic pressure associated with
ventilation. During normal vascular tone, the ICP and ABP recordings are
dissimilar and the compression effect is minimal. The compression effect
progressively reduces as tone is lost and the recordings become markedly
similar. The model is designed to gene rate a theoretical ICP wave for
different amounts of [PCO.sub.2] using a given APF waveform.
Coefficients of correlation are then calculated to demonstrate the model
performs as predicted.