Rheology of Human Blood, near and at Zero Flow

Merrill, Edward W.; Gilliland, E. R.; Cokelet, Giles C.; Shin, Hye‐Won; Britten, Anthony; Wells, Roe E.

doi:10.1016/s0006-3495(63)86816-2

Cited by 203 publications

(76 citation statements)

References 3 publications

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“…Accordingly, the blood was modeled as a non-Newtonian viscoelastic fluid, with density of q = 1.056 g/cm )3 and yield shear of 0.1 s )1 . The shear dependent viscosity was extracted by curve fitting experimental data of human blood viscosity (l) at 37°C and changing shear rates ( ¶U/ ¶y) 17 according to l = A ( ¶U/ ¶y) (B)1 ) + C (A = 26.314, B = 0.706814, and C = 3.117316 Â 10 )2 ), approximating l = 3.5 cPoise at elevated shear levels. 17 The calculations were performed for one cardiac cycle, corresponding to the waveform used in the DPIV (Fig.…”

Section: Methodsmentioning

confidence: 99%

DPIV Prediction of Flow Induced Platelet Activation—Comparison to Numerical Predictions

et al. 2007

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Abstract-Flow induced platelet activation (PA) can lead to platelet aggregation, deposition onto the blood vessel wall, and thrombus formation. PA was thoroughly studied under unidirectional flow conditions. However, in regions of complex flow, where the platelet is exposed to varying levels of shear stress for varying durations, the relationship between flow and PA is not well understood. Numerical models were developed for studying flow induced PA resulting from stress histories along Lagrangian trajectories in the flow field. However, experimental validation techniques such as Digital Particle Image Velocimetry (DPIV) were not extended to include such models. In this study, a general experimental tool for PA analysis by means of continuous DPIV was utilized and compared to numerical simulation in a model of coronary stenosis. A scaled up (5:1) 84% eccentric and axisymetric coronary stenosis model was used for analysis of shear stress and exposure time along particle trajectories. Flow induced PA was measured using the PA State (PAS) assay. An algorithm for computing the PA level in pertinent trajectories was developed as a tool for extracting information from DPIV measurements for predicting the flow induced thrombogenic potential. CFD, DPIV and PAS assay results agreed well in predicting the level of PA. In addition, the same trend predicted by the DPIV was measured in vitro using the Platelet Activity State (PAS) assay, namely, that the symmetric stenosis activated the platelets more as compared to the eccentric stenosis.

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Section: Methodsmentioning

confidence: 99%

DPIV Prediction of Flow Induced Platelet Activation—Comparison to Numerical Predictions

et al. 2007

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“…Modern rheometry techniques and instruments yield reliable measurements of macroscopic properties of cell suspensions with ever-improving convenience-for example, the bulk properties of blood measured in various laboratories (1)(2)(3)(4)(5)(6). Virtually all bloodviscosity measurements are necessarily in vitro, and before newly drawn blood is introduced into a viscometer it must at least be stabilized with an anticoagulant, which is then called "whole blood."…”

mentioning

confidence: 99%

“…Virtually all bloodviscosity measurements are necessarily in vitro, and before newly drawn blood is introduced into a viscometer it must at least be stabilized with an anticoagulant, which is then called "whole blood." Under flow conditions at small deformation rates, the RBCs in whole blood have been observed to aggregate into structures called "rouleaux," which resemble stacks of coins (1,(7)(8)(9).…”

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confidence: 99%

Predicting human blood viscosity in silico

Fedosov

Pan²,

Caswell³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

307

246

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The viscosity of blood has long been used as an indicator in the understanding and treatment of disease, and the advent of modern viscometers allows its measurement with ever-improving clinical convenience. However, these advances have not been matched by theoretical developments that can yield a quantitative understanding of blood's microrheology and its possible connection to relevant biomolecules (e.g., fibrinogen). Using coarse-grained molecular dynamics and two different red blood cell models, we accurately predict the dependence of blood viscosity on shear rate and hematocrit. We explicitly represent cell-cell interactions and identify the types and sizes of reversible rouleaux structures that yield a tremendous increase of blood viscosity at low shear rates. We also present the first quantitative estimates of the magnitude of adhesive forces between red cells. In addition, our simulations support the hypothesis, previously deduced from experiments, of yield stress as an indicator of cell aggregation. This non-Newtonian behavior is analyzed and related to the suspension's microstructure, deformation, and dynamics of single red blood cells. The most complex cell dynamics occurs in the intermediate shear rate regime, where individual cells experience severe deformation and transient folded conformations. The generality of these cell models together with single-cell measurements points to the future prediction of blood-viscosity anomalies and the corresponding microstructures associated with various diseases (e.g., malaria, AIDS, and diabetes mellitus). The models can easily be adapted to tune the properties of a much wider class of complex fluids including capsule and vesicle suspensions.blood rheology | blood modeling | shear thinning | aggregation force | dissipative particle dynamics R heological and material properties of cell, capsule, and vesicle suspensions have many applications in medicine, biology, engineering, and materials science. One of the main examples of such suspensions is blood, which consists of RBCs, predominant by volume, and a small fraction of other cells and proteins suspended in the plasma. Understanding blood flow and its relation to cellular properties and interactions may lead to advances in biomedical applications (e.g., drug delivery, blood substitutes). Moreover, a change in blood rheological and flow properties is often associated with hematological diseases or disorders (e.g., sickle-cell anemia, malaria), and therefore the viscosity of blood has long been used as an indicator in the understanding and treatment of disease.Modern rheometry techniques and instruments yield reliable measurements of macroscopic properties of cell suspensions with ever-improving convenience-for example, the bulk properties of blood measured in various laboratories (1-6). Virtually all bloodviscosity measurements are necessarily in vitro, and before newly drawn blood is introduced into a viscometer it must at least be stabilized with an anticoagulant, which is then called "whole blood." Under flow...

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“…The response of embryonic vasculature to the intervention will be first clarified when we can measure the vascular resistance of the embryo alone in separation from placental circulation. It is unlikely that decrease of viscosity of the embryonic blood due to the elevation of temperature by only 5°C is large enough to correspond totally to the change of vascular resistance of the umbilical artery (10). We have wondered how the vascular bed of the placenta with its sinusoidal structure could have actively dilated in any circumstance.…”

Section: Discussionmentioning

confidence: 99%

Effects of Environmental Hyperthermia on Cardiovascular Function in the Rat Embryo

et al. 1991

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ABSTRACT. Effects of hyperthermia on the cardiovascular function of the mammalian embryo have not been well defined. The effect of hyperthermia on the blood flow and umbilical artery blood pressure was studied in rat embryos at gestational d 12 by using a method developed in our laboratory. When the temperature was changed from 37 to 42"C, the heart rate increased by 15% (n = 33). Mean umbilical artery blood pressure, measured by a servo-null micropressure system, decreased from 0.64 + 0.05 to 0.53 f 0.04 mm Hg (n = 11), whereas blood flow velocity at the conotruncus, a measure of cardiac output, obtained by a 20-MHz pulsed Doppler ultrasound flowmeter, increased by 36 f 11% (n = 11). Mean umbilical artery blood flow increased by 66 f 13% (n = 11) and its vascular resistance, calculated by ratio analysis, decreased from 3.7 (median) to 1.8 units. These changes returned to baseline values when the temperature was returned to 37°C. The change in blood pressure was different from that seen in the chick embryo, indicating that there is species difference in the hemodynamic effect. (Pediatr Res 30: 505-508, 1991) Hyperthermia is an environmental hazard to the mammalian embryo and is reported to be a teratogen, although this is not unanimously accepted (1-3). We previously found that hyperthermia increased blood pressure and cardiac output in chick embryos (4), which was considered to be causally related to the cardiovascular pathogenesis, at least in part. The effects of high temperature on cardiovascular function of the mammalian embryo, however, have not been studied. We have found that various interventions have different hemodynamic effects in chick and rat embryos (5). Therefore, the purpose of the present study was to investigate the hemodynamic effect of high temperature in the rat embryo and to compare the results with those in the chick embryo. MATERIALS AND METHODSisolated and put into a bath of Hanks' solution. Then, a part of the uterus wall was pinned down on the rubber sheet at the bottom of the bath and the yolk sac was opened to expose the embryo and umbilical vessels (5, 6). In the modified system, the perfusate was bubbled with 100% oxygen gas in a glass flask, which was warmed to 37°C on an electric heating pan, and a constant flow through the bath was maintained by a roller pump (5) (Fig. 1). The Poz of perfusate in the bath ranged from 60 to 67 kPa. The hemodynamic condition was stable for at least 30 min in this system.The umbilical artery blood pressure was measured with a servo-null micro-pressure system (model 900; WP Instruments, Inc., Sarasota, FL) by inserting a micro-glass pipette into the umbilical artery. The blood flow velocity at the conotruncal region was obtained with a 20-MHz pulsed Doppler velocity meter (University of Iowa) by placing a piezoelectric crystal as the Doppler beam passed through the axis of the outflow tract of the embryo heart. Although cardiac output could not be obtained because simultaneous measurement of the diameter of that portion was not feasible, any cha...

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Rheology of Human Blood, near and at Zero Flow

Cited by 203 publications

References 3 publications

DPIV Prediction of Flow Induced Platelet Activation—Comparison to Numerical Predictions

DPIV Prediction of Flow Induced Platelet Activation—Comparison to Numerical Predictions

Predicting human blood viscosity in silico

Effects of Environmental Hyperthermia on Cardiovascular Function in the Rat Embryo

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