Rheology of blood

Cerny, L.C.; Cook, F.B.; Walker, C. C.

doi:10.1152/ajplegacy.1962.202.6.1188

Cited by 15 publications

(5 citation statements)

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“…Blood viscosity is also dependent upon a number of other factors, including plasma viscosity (Goldsmith and Skalak, 1975), temperature (Barbee, 1973;Chen and Chien, 1978), the deformability of RBCs (Chien ~al., 1967) and the blood Bet (Cerny~ al., 1962;Skalak~ al., 1972). …”

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confidence: 99%

Aspects of cardiovascular oxygen transport in vertebrates

Hedrick¹

2000

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The hematological and rheological characteristics of blood from a number of vertebrates was compared to assess possible species differences in blood viscosity that may influence cardiovascular oxygen The predicted in vitro optimal hematocrit (Bo) for oxygen transport was determined for each species and compared to the observed ill.1i!2. hematocrit (Bet). There was a very close correspondence between the predicted Bo and the observed normal Bet for the blood tested, with the exception of elephant seal (Mirounga angustirostris) blood.Resting and maxim.al rates of blood flow at lOoc, 2ooc and 3oocwere measured in Bufo marinus with magnetic blood flow probes to assess the relative contributions of heart rate, systemic arch pulse volume and arteriovenous (A-V) oxygen difference to increased oxygen consumption (V02). A-V 02 difference accounted for 100%, 84% and 88% of the increase in V02 during maximal exercise at iooc, 2ooc and 3ooc, respectively.Systemic arch pulse volume remained nearly constant over a wide range of heart~rates (15-115 beats min-l)thus contributing little to increased cardiac output during increased V02.Changes in blood flow rates through the systemic arches of resting toads were predicted by in vitro changes in blood viscosity over a 1ooc to 30oc interval. Resting animals did not appear to actively compensate for the passive alterations in viscosity that seemed to influence blood flow rates in viyo.

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confidence: 99%

Aspects of cardiovascular oxygen transport in vertebrates

Hedrick¹

2000

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“…A fluid with constant viscosity was used instead of blood which is a suspension of formed elements and exhibits non-Newtonian behavior. However, at shear rates greater than 200 s"' the viscosity of blood (hematocrit 44 percent) is constant and independent of the capillary radius (r > 0.1 mm) [7]. Considering the relatively high shear rates in a stenosed artery and the fact that even for the most severe stenosis models the minimum hydraulic diameter was larger than 0.2 mm, treating blood as a homogeneous, Newtonian fluid appears a reasonable assumption for the purposes of this study.…”

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confidence: 99%

Fluid Dynamics of a Partially Collapsible Stenosis in a Flow Model of the Coronary Circulation

Siebes

Campbell²,

D’Argenio

1996

Journal of Biomechanical Engineering

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The influence of passive vasomotion on the pressure drop-flow (delta P-Q) characteristics of a partially compliant stenosis was studied in an in vitro model of the coronary circulation. Twelve stenosis models of different severities (50 to 90 percent area reduction) and degrees of flexible wall (0 to 1/2 of the wall circumference) were inserted into thin-walled latex tubing and pressure and flow data were collected during simulated cardiac cycles. In general, the pressure drop increased with increasing fraction of flexible wall for a given flow rate and stenosis severity. The magnitude of this effect was directly dependent upon the underlying stenosis severity. The diastolic delta P-Q relationship of severe, compliant models exhibited features of partial collapse with an increase in pressure drop at a decreasing flow rate. It is concluded that passive vasomotion of a normal wall segment at an eccentric stenosis in response to periodic changes in intraluminal pressure causes dimensional changes in the residual lumen area which can strongly affect the hemodynamic characteristics of the stenosis during the cardiac cycle. This mechanism may have important implications for the onset of plaque fracture and the prediction of the functional significance of a coronary stenosis based on quantitative angiogram analysis.

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“…In general, blood is composed of red blood cell (RBC), white blood cell (WBC, leukocytes), and platelets suspended in a fluid medium. Even though blood viscosity is considered a non-Newtonian fluid with shearing thinning properties [ 19 ], blood has a Newtonian behavior with viscosity of 1.6 × 10 −3 N · s/m 2 [ 20 ]. This study models blood as a generalized Newtonian fluid using Carreau-Yasuda model [ 21 , 22 ]:

where μ ∞ is the viscosity at infinite shear rate, 0.0035 kg/m · s, μ 0 is the viscosity at zero shear rate, 0.16 kg/m · s, nondimensional power index n = 0.2128, a = 0.64, and the relaxation time λ = 8.2 s.

(rad/s) represents the shear rate at which a shearing deformation is applied to blood.…”

Section: Formulation Of the Problemmentioning

confidence: 99%

Mathematical Modeling of Radiofrequency Ablation for Varicose Veins

Choi

Kwak

Seo

2014

Computational and Mathematical Methods in Medicine

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We present a three-dimensional mathematical model for the study of radiofrequency ablation (RFA) with blood flow for varicose vein. The model designed to analyze temperature distribution heated by radiofrequency energy and cooled by blood flow includes a cylindrically symmetric blood vessel with a homogeneous vein wall. The simulated blood velocity conditions are U = 0, 1, 2.5, 5, 10, 20, and 40 mm/s. The lower the blood velocity, the higher the temperature in the vein wall and the greater the tissue damage. The region that is influenced by temperature in the case of the stagnant flow occupies approximately 28.5% of the whole geometry, while the region that is influenced by temperature in the case of continuously moving electrode against the flow direction is about 50%. The generated RF energy induces a temperature rise of the blood in the lumen and leads to an occlusion of the blood vessel. The result of the study demonstrated that higher blood velocity led to smaller thermal region and lower ablation efficiency. Since the peak temperature along the venous wall depends on the blood velocity and pullback velocity, the temperature distribution in the model influences ablation efficiency. The vein wall absorbs more energy in the low pullback velocity than in the high one.

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Rheology of blood

Cited by 15 publications

References 0 publications

Aspects of cardiovascular oxygen transport in vertebrates

Aspects of cardiovascular oxygen transport in vertebrates

Fluid Dynamics of a Partially Collapsible Stenosis in a Flow Model of the Coronary Circulation

Mathematical Modeling of Radiofrequency Ablation for Varicose Veins

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