A New Approach to Model Confined Suspensions Flows in Complex Networks: Application to Blood Flow

Guibert, Romain; Fonta, Caroline; Plouraboué, Franck

doi:10.1007/s11242-009-9492-0

Cited by 22 publications

(35 citation statements)

References 32 publications

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“…12,13,[21][22][23]27,36,38,41,42 In these works, the complex rheological properties of blood flow in microcirculation, especially the phase separation effect, are either described by empirical laws obtained by least-square adjustment to experimental results (e.g., Refs. 21 and 36), theoretically derived assuming a given RBC flow regime (e.g., single file RBC flows in narrow capillaries 27 ), or modeled in an ad hoc fashion.…”

Section: Introductionmentioning

confidence: 99%

Going beyond 20 μm-sized channels for studying red blood cell phase separation in microfluidic bifurcations

et al. 2016

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Despite the development of microfluidics, experimental challenges are considerable for achieving a quantitative study of phase separation, i.e., the non-proportional distribution of Red Blood Cells (RBCs) and suspending fluid, in microfluidic bifurcations with channels smaller than 20 lm. Yet, a basic understanding of phase separation in such small vessels is needed for understanding the coupling between microvascular network architecture and dynamics at larger scale. Here, we present the experimental methodologies and measurement techniques developed for that purpose for RBC concentrations (tube hematocrits) ranging between 2% and 20%. The maximal RBC velocity profile is directly measured by a temporal cross-correlation technique which enables to capture the RBC slip velocity at walls with high resolution, highlighting two different regimes (flat and more blunted ones) as a function of RBC confinement. The tube hematocrit is independently measured by a photometric technique. The RBC and suspending fluid flow rates are then deduced assuming the velocity profile of a Newtonian fluid with no slip at walls for the latter. The accuracy of this combination of techniques is demonstrated by comparison with reference measurements and verification of RBC and suspending fluid mass conservation at individual bifurcations. The present methodologies are much more accurate, with less than 15% relative errors, than the ones used in previous in vivo experiments. Their potential for studying steady state phase separation is demonstrated, highlighting an unexpected decrease of phase separation with increasing hematocrit in symmetrical, but not asymmetrical, bifurcations and providing new reference data in regimes where in vitro results were previously lacking. Published by AIP Publishing. [http://dx

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Section: Introductionmentioning

confidence: 99%

Going beyond 20 μm-sized channels for studying red blood cell phase separation in microfluidic bifurcations

et al. 2016

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“…Imposing flow conservation while solving only the pressure values at bifurcations drastically reduces the number of unknown variables to be found. Our previous study has shown that, despite what would be expected from an analysis of small networks only (Guibert et al, 2010b), simulations in realistic networks are not sensitive to the phase separation mechanism as far as the pressure distribution and local flows are concerned. In contrast, we found a strong dependence on the apparent viscosity model.…”

Section: Vessel Network Imaging and Blood Flow Simulationmentioning

confidence: 88%

Coupling and robustness of intra-cortical vascular territories

et al. 2012

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Vascular domains have been described as being coupled to neuronal functional units enabling dynamic blood supply to the cerebral cyto-architecture. Recent experiments have shown that penetrating arterioles of the grey matter are the building blocks for such units. Nevertheless, vascular territories are still poorly known, as the collection and analysis of large three-dimensional micro-vascular networks are difficult. By using an exhaustive reconstruction of the micro-vascular network in an 18 mm(3) volume of marmoset cerebral cortex, we numerically computed the blood flow in each blood vessel. We thus defined arterial and venular territories and examined their overlap. A large part of the intracortical vascular network was found to be supplied by several arteries and drained by several venules. We quantified this multiple potential to compensate for deficiencies by introducing a new robustness parameter. Robustness proved to be positively correlated with cortical depth and a systematic investigation of coupling maps indicated local patterns of overlap between neighbouring arteries and neighbouring venules. However, arterio-venular coupling did not have a spatial pattern of overlap but showed locally preferential functional coupling, especially of one artery with two venules, supporting the notion of vascular units. We concluded that intra-cortical perfusion in the primate was characterised by both very narrow functional beds and a large capacity for compensatory redistribution, far beyond the nearest neighbour collaterals.

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“…In vivo studies have shown that strong heterogeneities of the haematocrit exist in the smallest capillaries. This phase separation leads on average to higher haematocrits in high flow rate branches at bifurcations, and is directly related to the spatial distribution of cells upstream (Guibert et al 2010;Doyeux et al 2011).…”

Section: Introductionmentioning

confidence: 98%