Development and validation of an integrated computational model of cerebral blood flow and oxygenation.
BACKGROUND
Various groups have constructed simulations and models of cerebral blood flow and oxygenation, each with its strengths and weaknesses. We describe the development and validation of a novel computational model, the Nottingham cerebral simulator (NCS), designed for experimental and teaching use.


METHODS
Physiological hypotheses were converted into differential equations; these are solved numerically with respect to time. A battery of tests was derived from published literature against which to test the simulation: static and dynamic autoregulation responses; carbon dioxide reactivity; brain tissue oxygenation. The NCS was programmed to simulate the methodologies of published experiments and the results of the simulation and the published data were compared.


RESULTS
The NCS results are qualitatively and quantitatively similar to published data. The values for regulatory indices were (published values in parentheses): index of autoregulation 0.9 (0.9); transient hyperemic response ratio 1.3 (1.3), carbon dioxide reactivity 2.4%-4.7% mm Hg(-1) (2-4.5); brain tissue oxygen tension 22 mm Hg (20-100).


CONCLUSIONS
The NCS is a credible model of cerebral blood flow and oxygenation, which warrants further use as an experimental and teaching tool.
Moppett
Iain K
IK
Division of Anaesthesia and Intensive Care, Queen's Medical Centre Campus, Nottingham University Hospitals, Nottingham, UK. iain.moppett@nottingham.ac.uk
Hardman
Jonathan G
JG
D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001921:Brain / Q000378:metabolism; D002245:Carbon Dioxide / Q000097:blood; D002560:Cerebrovascular Circulation; D003198:Computer Simulation; D006706:Homeostasis; D006801:Humans; D007427:Intracranial Pressure; D020768:Middle Cerebral Artery; D008955:Models, Cardiovascular; D010100:Oxygen / Q000097:blood* / Q000378:metabolism; D012986:Software Validation; D014655:Vascular Resistance
D002245:Carbon Dioxide; D010100:Oxygen