Blood flow in microvascular networks. Experiments and simulation

A. R. Pries, Timothy W Secomb, P. Gaehtgens, J. F. Gross

Research output: Contribution to journalArticle

372 Citations (Scopus)

Abstract

A theoretical model has been developed to simulate blood flow through large microcirculatory networks. The model takes into account the dependence of apparent viscosity of blood on vessel diameter and hematocrit (the Fahraeus-Lindqvist effect), the reduction of intravascular hematocrit relative to the inflow hematocrit of a vessel (the Fahraeus effect), and the disproportionate distribution of red blood cells and plasma at arteriolar bifurcations (phase separation). The model was used to simulate flow in three microvascular networks in the rat mesentery with 436, 583, and 913 vessel segments, respectively, using experimental data (length, diameter, and topological organization) obtained from the same networks. Measurements of hematocrit and flow direction in all vessel segments of these networks tested the validity of model results. These tests demonstrate that the prediction of parameters for individual vessel segments in large networks exhibits a high degree of uncertainty; for example, the squared coefficient of correlation between predicted and measured hematocrit of single vessel segments ranges only between 0.15 and 0.33. In contrast, the simulation of integrated characteristics of the network hemodynamics, such as the mean segment hematocrit or the distribution of blood flow velocities, is very precise. In addition, the following conclusions were derived from the comparison of predicted and measured values: 1) The low capillary hematocrits found in mesenteric microcirculatory networks as well as their heterogeneity can be explained on the basis of the Fahraeus effect and phase-separation phenomena. 2) The apparent viscosity of blood in vessels of the investigated tissue with diameters less than 15 μm is substantially higher than expected compared with measurements in glass tubes with the same diameter.

Original languageEnglish (US)
Pages (from-to)826-834
Number of pages9
JournalCirculation Research
Volume67
Issue number4
StatePublished - 1990
Externally publishedYes

Fingerprint

Microvessels
Hematocrit
Viscosity
Blood Vessels
Mesentery
Blood Flow Velocity
Reproducibility of Results
Uncertainty
Glass
Theoretical Models
Erythrocytes
Hemodynamics

Keywords

  • Fahraeus effect
  • Fahraeus-Lindqvist effect
  • Microvascular networks
  • Microvessel hematocrit

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Pries, A. R., Secomb, T. W., Gaehtgens, P., & Gross, J. F. (1990). Blood flow in microvascular networks. Experiments and simulation. Circulation Research, 67(4), 826-834.

Blood flow in microvascular networks. Experiments and simulation. / Pries, A. R.; Secomb, Timothy W; Gaehtgens, P.; Gross, J. F.

In: Circulation Research, Vol. 67, No. 4, 1990, p. 826-834.

Research output: Contribution to journalArticle

Pries, AR, Secomb, TW, Gaehtgens, P & Gross, JF 1990, 'Blood flow in microvascular networks. Experiments and simulation', Circulation Research, vol. 67, no. 4, pp. 826-834.
Pries, A. R. ; Secomb, Timothy W ; Gaehtgens, P. ; Gross, J. F. / Blood flow in microvascular networks. Experiments and simulation. In: Circulation Research. 1990 ; Vol. 67, No. 4. pp. 826-834.
@article{31f228596e354e94921dea08ab108819,
title = "Blood flow in microvascular networks. Experiments and simulation",
abstract = "A theoretical model has been developed to simulate blood flow through large microcirculatory networks. The model takes into account the dependence of apparent viscosity of blood on vessel diameter and hematocrit (the Fahraeus-Lindqvist effect), the reduction of intravascular hematocrit relative to the inflow hematocrit of a vessel (the Fahraeus effect), and the disproportionate distribution of red blood cells and plasma at arteriolar bifurcations (phase separation). The model was used to simulate flow in three microvascular networks in the rat mesentery with 436, 583, and 913 vessel segments, respectively, using experimental data (length, diameter, and topological organization) obtained from the same networks. Measurements of hematocrit and flow direction in all vessel segments of these networks tested the validity of model results. These tests demonstrate that the prediction of parameters for individual vessel segments in large networks exhibits a high degree of uncertainty; for example, the squared coefficient of correlation between predicted and measured hematocrit of single vessel segments ranges only between 0.15 and 0.33. In contrast, the simulation of integrated characteristics of the network hemodynamics, such as the mean segment hematocrit or the distribution of blood flow velocities, is very precise. In addition, the following conclusions were derived from the comparison of predicted and measured values: 1) The low capillary hematocrits found in mesenteric microcirculatory networks as well as their heterogeneity can be explained on the basis of the Fahraeus effect and phase-separation phenomena. 2) The apparent viscosity of blood in vessels of the investigated tissue with diameters less than 15 μm is substantially higher than expected compared with measurements in glass tubes with the same diameter.",
keywords = "Fahraeus effect, Fahraeus-Lindqvist effect, Microvascular networks, Microvessel hematocrit",
author = "Pries, {A. R.} and Secomb, {Timothy W} and P. Gaehtgens and Gross, {J. F.}",
year = "1990",
language = "English (US)",
volume = "67",
pages = "826--834",
journal = "Circulation Research",
issn = "0009-7330",
publisher = "Lippincott Williams and Wilkins",
number = "4",

}

TY - JOUR

T1 - Blood flow in microvascular networks. Experiments and simulation

AU - Pries, A. R.

AU - Secomb, Timothy W

AU - Gaehtgens, P.

AU - Gross, J. F.

PY - 1990

Y1 - 1990

N2 - A theoretical model has been developed to simulate blood flow through large microcirculatory networks. The model takes into account the dependence of apparent viscosity of blood on vessel diameter and hematocrit (the Fahraeus-Lindqvist effect), the reduction of intravascular hematocrit relative to the inflow hematocrit of a vessel (the Fahraeus effect), and the disproportionate distribution of red blood cells and plasma at arteriolar bifurcations (phase separation). The model was used to simulate flow in three microvascular networks in the rat mesentery with 436, 583, and 913 vessel segments, respectively, using experimental data (length, diameter, and topological organization) obtained from the same networks. Measurements of hematocrit and flow direction in all vessel segments of these networks tested the validity of model results. These tests demonstrate that the prediction of parameters for individual vessel segments in large networks exhibits a high degree of uncertainty; for example, the squared coefficient of correlation between predicted and measured hematocrit of single vessel segments ranges only between 0.15 and 0.33. In contrast, the simulation of integrated characteristics of the network hemodynamics, such as the mean segment hematocrit or the distribution of blood flow velocities, is very precise. In addition, the following conclusions were derived from the comparison of predicted and measured values: 1) The low capillary hematocrits found in mesenteric microcirculatory networks as well as their heterogeneity can be explained on the basis of the Fahraeus effect and phase-separation phenomena. 2) The apparent viscosity of blood in vessels of the investigated tissue with diameters less than 15 μm is substantially higher than expected compared with measurements in glass tubes with the same diameter.

AB - A theoretical model has been developed to simulate blood flow through large microcirculatory networks. The model takes into account the dependence of apparent viscosity of blood on vessel diameter and hematocrit (the Fahraeus-Lindqvist effect), the reduction of intravascular hematocrit relative to the inflow hematocrit of a vessel (the Fahraeus effect), and the disproportionate distribution of red blood cells and plasma at arteriolar bifurcations (phase separation). The model was used to simulate flow in three microvascular networks in the rat mesentery with 436, 583, and 913 vessel segments, respectively, using experimental data (length, diameter, and topological organization) obtained from the same networks. Measurements of hematocrit and flow direction in all vessel segments of these networks tested the validity of model results. These tests demonstrate that the prediction of parameters for individual vessel segments in large networks exhibits a high degree of uncertainty; for example, the squared coefficient of correlation between predicted and measured hematocrit of single vessel segments ranges only between 0.15 and 0.33. In contrast, the simulation of integrated characteristics of the network hemodynamics, such as the mean segment hematocrit or the distribution of blood flow velocities, is very precise. In addition, the following conclusions were derived from the comparison of predicted and measured values: 1) The low capillary hematocrits found in mesenteric microcirculatory networks as well as their heterogeneity can be explained on the basis of the Fahraeus effect and phase-separation phenomena. 2) The apparent viscosity of blood in vessels of the investigated tissue with diameters less than 15 μm is substantially higher than expected compared with measurements in glass tubes with the same diameter.

KW - Fahraeus effect

KW - Fahraeus-Lindqvist effect

KW - Microvascular networks

KW - Microvessel hematocrit

UR - http://www.scopus.com/inward/record.url?scp=0025140634&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0025140634&partnerID=8YFLogxK

M3 - Article

C2 - 2208609

AN - SCOPUS:0025140634

VL - 67

SP - 826

EP - 834

JO - Circulation Research

JF - Circulation Research

SN - 0009-7330

IS - 4

ER -