Peculiarities of Brain's Blood Flow : Role of Carbon Dioxide

TL;DR

This paper presents a simple physical model relating cerebral blood flow to carbon dioxide levels, enabling cross-species data transformation and enhancing understanding of blood flow regulation.

Contribution

A novel four-parameter formula model that accurately fits cerebral blood flow data across different species and allows data rescaling between animals and humans.

Findings

Model fits experimental data from monkeys, rats, and humans.

Transformation formula enables data rescaling between species.

Model simplifies analysis of cerebral blood flow regulation.

Abstract

Among the major factors controlling the cerebral blood flow (CBF), the effect of PaCO2 is peculiar in that it violates autoregulatory CBF mechanisms and allows to explore the full range of the CBF. This research resulted in a simple physical model, with a four parameter formula, relating the CBF to PaCO2. The parameters can be extracted in an easy manner, directly from the experimental data. With this model earlier experimental data sets of Rhesus monkeys and rats were well fitted. Human data were also fitted with this model. Exact formulae were found, which can be used to transform the fits of one animal to the fits of another one. The merit of this transformation is that it enable us the use of rats data as monkeys data simply by rescaling the PaCO2 values and the CBF data. This transformation makes possible the use of experimental animal data instead of human ones.