scholarly journals Numerical simulation of spatiotemporal red blood cell aggregation under sinusoidal pulsatile flow

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cheong-Ah Lee ◽  
Dong-Guk Paeng
Keyword(s):  
Shear Rate ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Pulsatile Flow ◽  
Cell Aggregation ◽  
Spatiotemporal Variation ◽  
Shear Rates ◽  
Red Blood Cell Aggregation ◽  
Axial Shear ◽  
Rbc Aggregation

AbstractPrevious studies on red blood cell (RBC) aggregation have elucidated the inverse relationship between shear rate and RBC aggregation under Poiseuille flow. However, the local parabolic rouleaux pattern in the arterial flow observed in ultrasonic imaging cannot be explained by shear rate alone. A quantitative approach is required to analyze the spatiotemporal variation in arterial pulsatile flow and the resulting RBC aggregation. In this work, a 2D RBC model was used to simulate RBC motion driven by interactional and hydrodynamic forces based on the depletion theory of the RBC mechanism. We focused on the interaction between the spatial distribution of shear rate and the dynamic motion of RBC aggregation under sinusoidal pulsatile flow. We introduced two components of shear rate, namely, the radial and axial shear rates, to understand the effect of sinusoidal pulsatile flow on RBC aggregation. The simulation results demonstrated that specific ranges of the axial shear rate and its ratio with radial shear rate strongly affected local RBC aggregation and parabolic rouleaux formation. These findings are important, as they indicate that the spatiotemporal variation in shear rate has a crucial role in the aggregate formation and local parabolic rouleaux under pulsatile flow.

scholarly journals Red blood cell (RBC) aggregation and its influence on non-Newtonian nature of blood in microvasculature

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Chitra Murali ◽  
Perumal Nithiarasu
Keyword(s):  
Blood Flow ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Cell Aggregation ◽  
Time Dependent ◽  
Shear Rates ◽  
Red Blood Cell Aggregation ◽  
Significant Difference ◽  
Rbc Aggregation ◽  
Rouleaux Formation

AbstractA robust computational model is proposed to investigate the non-Newtonian nature of blood flow due to rouleaux formation in microvasculature. The model consists of appropriate forces responsible for red blood cell (RBC) aggregation in the microvasculature, tracking of RBCs, and coupling between plasma flow and RBCs. The RBC aggregation results have been compared against the available data. The importance of different hydrodynamic forces on red blood cell aggregation has been delineated by comparing the time dependent path of the RBCs. The rheological changes to the blood flow have been investigated under different shear rates and hematocrit values and quantified with and without RBC aggregation. The results obtained in terms of wall shear stress (WSS) and blood viscosity indicate a significant difference between Newtonian and powerlaw fluid assumptions.

S5.2. Ultrasonic estimation of red blood cell aggregation in a controlled shear rate

Biorheology ◽  
1995 ◽  
Vol 32 (2-3) ◽  
pp. 123-123
Author(s):  
L HAIDER ◽  
P BERTHOLOM ◽  
C TOURAIN ◽  
R GUILLET ◽  
M BOYNARD
Keyword(s):  
Shear Rate ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Cell Aggregation ◽  
Red Blood Cell Aggregation ◽  
Blood Cell Aggregation

scholarly journals On the use of photoacoustics to detect red blood cell aggregation

2021 ◽  
Author(s):  
Michael C. Kolios
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Spectral Power ◽  
Aggregate Size ◽  
Cell Aggregation ◽  
Dominant Frequency ◽  
Red Blood Cell Aggregation ◽  
Theoretical Predictions ◽  
Rbc Aggregation ◽  
Simulation Results

The feasibility of detecting red blood cell (RBC) aggregation with photoacoustics (PAs) was investigated theoretically and experimentally using human and porcine RBCs. The theoretical PA signals and spectra generated from such samples were examined for several hematocrit levels and aggregates sizes. The effect of a finite transducer bandwidth on the received PA signal was also examined. The simulation results suggest that the dominant frequency of the PA signals from non-aggregated RBCs decreases towards clinical frequency ranges as the aggregate size increases. The experimentally measured mean spectral power increased by ~6 dB for the largest aggregate compared to the non-aggregated samples. Such results confirm the theoretical predictions and illustrate the potential of using PA imaging for detecting RBC aggregation.

Effects of increased plasma viscosity and red blood cell aggregation on blood viscosity in vivo

1981 ◽  
Vol 241 (4) ◽  
pp. H513-H518 ◽  
Author(s):  
L. Gustafsson ◽  
L. Appelgren ◽  
H. E. Myrvold
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Apparent Viscosity ◽  
Cell Aggregation ◽  
Plasma Viscosity ◽  
Pressure Flow ◽  
Red Blood Cell Aggregation ◽  
Rbc Aggregation

The effects of increased plasma viscosity and induced red blood cell (RBC) aggregation on apparent viscosity of blood in vivo in the skeletal muscle of the dog were studied. Apparent viscosity in vivo was determined in the isolated and vasodilated calf muscles of one hindlimb by comparing pressure-flow relationships for RBC suspensions with pressure-flow relationships for a Newtonian solution of known viscosity. RBC suspensions of increased plasma viscosity with and without RBC aggregation were obtained by substituting plasma with isoviscous solutions of high- and low-molecular-weight dextran in saline. Hematocrits of the suspensions were adjusted to either 45 or 60%. The viscosities of the suspensions in vitro were determined in a Wells-Brookfield viscometer. Apparent viscosity of blood in vivo was found to be mainly dependent on the viscosity of plasma. RBC aggregation had no significant influence on the viscosity in vivo.

scholarly journals The Effect of Glucose and Poloxamer 188 on Red-Blood-Cell Aggregation

Metabolites ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 886
Author(s):  
Alicja Szołna-Chodór ◽  
Bronisław Grzegorzewski
Keyword(s):  
Mechanical Properties ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Cell Aggregation ◽  
Aggregation Index ◽  
Poloxamer 188 ◽  
Red Blood Cell Aggregation ◽  
Rbc Aggregation ◽  
Effect Of Glucose ◽  
Blood Cell Aggregation

Glucose metabolism disorders contribute to the development of various diseases. Numerous studies show that these disorders not only change the normal values of biochemical parameters but also affect the mechanical properties of blood. To show the influence of glucose and poloxamer 188 (P188) on the mechanical properties of a red-blood-cell (RBC) suspension, we studied the aggregation of the cells. To show the mechanisms of the mechanical properties of blood, we studied the effects of glucose and poloxamer 188 (P188) on red-blood-cell aggregation. We used a model in which cells were suspended in a dextran 70 solution at a concentration of 2 g/dL with glucose and P188 at concentrations of 0–3 g/dL and 0–3 mg/mL, respectively. RBC aggregation was determined using an aggregometer, and measurements were performed every 4 min for 1 h. Such a procedure enabled the incubation of RBCs in solution. The aggregation index determined from the obtained syllectograms was used as a measure of aggregation. Both the presence of glucose and that of P188 increased the aggregation index with the incubation time until saturation was reached. The time needed for the saturation of the aggregation index increased with increasing glucose and P188 concentrations. As the concentrations of these components increased, the joint effect of glucose and P188 increased the weakening of RBC aggregation. The mechanisms of the observed changes in RBC aggregation in glucose and P188 solutions are discussed.

Effect of erythrocyte aggregation on velocity profiles in venules

2001 ◽  
Vol 280 (1) ◽  
pp. H222-H236 ◽  
Author(s):  
Jeffrey J. Bishop ◽  
Patricia R. Nance ◽  
Aleksander S. Popel ◽  
Marcos Intaglietta ◽  
Paul C. Johnson
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Cell Aggregation ◽  
Velocity Profiles ◽  
Erythrocyte Aggregation ◽  
Shear Rates ◽  
Red Blood Cell Aggregation ◽  
Venous Resistance ◽  
Blood Cell Aggregation

A recent whole organ study in cat skeletal muscle showed that the increase in venous resistance seen at reduced arterial pressures is nearly abolished when the muscle is perfused with a nonaggregating red blood cell suspension. To explore a possible underlying mechanism, we tested the hypothesis that red blood cell aggregation alters flow patterns in vivo and leads to blunted red blood cell velocity profiles at reduced shear rates. With the use of fluorescently labeled red blood cells in tracer quantities and a video system equipped with a gated image intensifier, we obtained velocity profiles in venous microvessels (45–75 μm) of rat spinotrapezius muscle at centerline velocities between 0.3 and 14 mm/s (pseudoshear rates 3–120 s−1) under normal (nonaggregating) conditions and after induction of red blood cell aggregation with Dextran 500. Profiles are nearly parabolic (Poiseuille flow) over this flow rate range in the absence of aggregation. When aggregation is present, profiles are parabolic at high shear rates and become significantly blunted at pseudoshear rates of 40 s−1 and below. These results indicate a possible mechanism for increased venous resistance at reduced flows.

Effect of aggregation and shear rate on the dispersion of red blood cells flowing in venules

2002 ◽  
Vol 283 (5) ◽  
pp. H1985-H1996 ◽  
Author(s):  
Jeffrey J. Bishop ◽  
Aleksander S. Popel ◽  
Marcos Intaglietta ◽  
Paul C. Johnson
Keyword(s):  
Shear Rate ◽  
Blood Cell ◽  
Red Blood Cells ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Cell Aggregation ◽  
Radial Position ◽  
Red Blood Cell Aggregation ◽  
Blood Cell Aggregation

Previous in vitro studies of blood flow in small glass tubes have shown that red blood cells exhibit significant erratic deviations in the radial position in the laminar flow regime. The purpose of the present study was to assess the magnitude of this variability and that of velocity in vivo and the effect of red blood cell aggregation and shear rate upon them. With the use of a gated image intensifier and fluorescently labeled red blood cells in tracer quantities, we obtained multiple measurements of red blood cell radial and longitudinal positions at time intervals as short as 5 ms within single venous microvessels (diameter range 45–75 μm) of the rat spinotrapezius muscle. For nonaggregating red blood cells in the velocity range of 0.3–14 mm/s, the mean coefficient of variation of velocity was 16.9 ± 10.5% and the SD of the radial position was 1.98 ± 0.98 μm. Both quantities were inversely related to shear rate, and the former was significantly lowered on induction of red blood cell aggregation by the addition of Dextran 500 to the blood. The shear-induced random movements observed in this study may increase the radial transport of particles and solutes within the bloodstream by orders of magnitude.

Design of a Microfluidic System for Red Blood Cell Aggregation Investigation

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
R. Mehri ◽  
C. Mavriplis ◽  
M. Fenech
Keyword(s):  
Shear Rate ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Velocity Ratio ◽  
Cell Aggregation ◽  
Microfluidic System ◽  
Numerical Work ◽  
Constant Shear ◽  
Rbc Aggregation ◽  
Controlled Flow

The purpose of this paper is to design a microfluidic apparatus capable of providing controlled flow conditions suitable for red blood cell (RBC) aggregation analysis. The linear velocity engendered from the controlled flow provides constant shear rates used to qualitatively analyze RBC aggregates. The design of the apparatus is based on numerical and experimental work. The numerical work consists of 3D numerical simulations performed using a research computational fluid dynamics (CFD) solver, Nek5000, while the experiments are conducted using a microparticle image velocimetry system. A Newtonian model is tested numerically and experimentally, then blood is tested experimentally under several conditions (hematocrit, shear rate, and fluid suspension) to be compared to the simulation results. We find that using a velocity ratio of 4 between the two Newtonian fluids, the layer corresponding to blood expands to fill 35% of the channel thickness where the constant shear rate is achieved. For blood experiments, the velocity profile in the blood layer is approximately linear, resulting in the desired controlled conditions for the study of RBC aggregation under several flow scenarios.

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