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Theoretical Simulation of Oxygen Transport to Brain by Networks of Microvessels: Effects of Oxygen Supply and Demand on Tissue Hypoxia
Author(s) -
SECOMB T.W.,
HSU R.,
BEAMER N.B.,
COULL B.M.
Publication year - 2000
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1111/j.1549-8719.2000.tb00124.x
Subject(s) - oxygen , perfusion , hypoxia (environmental) , chemistry , blood flow , microcirculation , oxygen transport , oxygene , biomedical engineering , anatomy , biophysics , cardiology , medicine , biology , organic chemistry
Objective : Simulations of oxygen delivery by a three‐dimensional network of microvessels in rat cerebral cortex were used to examine how the distribution of partial pressure of oxygen (PO 2 ) in tissue depends on blood flow and oxygen consumption rates. Methods : Network geometry was deduced from previously published scanning electron micrographs of corrosion casts. A nonlinear least‐squares method, using images obtained at three different angles, was used to estimate vessel locations. The network consisted of 50 segments in a region 140 µm × 150 µm × 160 µm. A Green's function method was used to predict the PO 2 distribution. Effects of varying perfusion and consumption were examined, relative to a control state with consumption 10 cm 3 O 2 /100 g per min and perfusion 160 cm 3 /100 g per min. Results : In the control state, minimum tissue PO 2 was 7 mm Hg. A Krogh‐type model with the same density of vessels, but with uniform spacing, predicted a minimum tissue PO 2 of 23 mm Hg. For perfusion below 60% of control, tissue hypoxia (PO 2 <1 mm Hg) was predicted. When perfusion was reduced by 75%, the resulting hypoxia could be eliminated by a 31% reduction in oxygen consumption rate. Conclusions : The simulations suggest that tissue hypoxia resulting from a severe decrease in brain perfusion, as can occur in stroke, may be avoided by a moderate decrease in oxygen consumption rate.