Combined transfer function analysis and modelling of cerebral autoregulation
Journal
Annals of Biomedical Engineering
Journal Volume
34
Journal Issue
5
Pages
847-858
Date Issued
2006
Author(s)
Abstract
The clinical importance of cerebral autoregulation has resulted in a significant body of literature that attempts both to model the underlying physiological processes and to estimate the mathematical relationships between clinically measurable variables, the most common of which are Arterial Blood Pressure and Cerebral Blood Flow Velocity. These approaches have, however, rarely been used together to interpret clinical data. A simple model of cerebral autoregulation is thus proposed here, based on a flow dependent feedback mechanism with gain and time constant that adjusts arterial compliance. Analysis of this model shows that it closely approximates a second order system for typical values of physiological parameters. The model parameters can be optimally estimated from available experimental data for the Impulse Response (IR), yielding physiologically reasonable values, although there is one free parameter that must be fixed. The effects of changes in feedback gain and time constant are found to be significant on the predicted IR and can thus be estimated robustly from experimental data. The effects of elevated baseline Intracranial Pressure (ICP) are found to be exactly equivalent to a reduced feedback gain, although the solution is much less sensitive to the former effect. A transfer function approach can be used to estimate autoregulation status clinically using a physiologically-based model, thus providing greater insight into the processes that govern cerebral autoregulation. ? 2006 Biomedical Engineering Society.
Subjects
Arterial Blood Pressure
Autoregulation
Feedback gain
Blood vessels
Frequency response
Impulse response
Medical applications
Physiological models
Transfer functions
Biological organs
algorithm
animal
article
biological model
blood flow velocity
blood pressure
brain
brain circulation
computer simulation
feedback system
hemostasis
human
physiology
vascularization
Algorithms
Animals
Blood Flow Velocity
Blood Pressure
Brain
Cerebrovascular Circulation
Computer Simulation
Feedback
Hemostasis
Humans
Models, Cardiovascular
SDGs
Type
journal article