(234l) Comparison of Simple Rheological Models in Fitting and Predicting Steady State and Transient Blood Rheology

Michael Deegan, Evan Ousley and Matthew J. Armstrong

Department of Chemistry and Life Science, United States Military Academy, West Point, NY 10996

Comparison of Simple Rheological Models in Fitting and Predicting Steady State and Transient Blood Rheology

Many complex materials have thixotropic behaviors, displaying time dependent viscous and elastic properties that are a function of microstructure. Some examples of thixotropic materials are aqueous nuclear waste, crude oil, and paints. Another example is blood. Modeling the behavior of these materials allows us to better understand how they can be used effectively in their respective industry [1,2]. We have characterized human blood using published steady state data and different models from literature. First, we looked at data from previous rheological experiments (Moreno and Sousa) [3,4] done on blood and modeled them using nine different simple models. Using the best model, we predicted small amplitude oscillatory shear (SAOS) with our own parameter determination technique and used two published transient models to predict large amplitude oscillatory shear (LAOS) and SAOS.

We characterize blood to develop better models, and evolve strategies to give way to better understanding of blood to facilitate benchmarking blood’s “normal” rheological fingerprint, with a view toward a methodology to diagnose pathologies based on rheological deviations from blood’s baseline mechanical properties. Based on the biochemistry of blood, its fluid mechanics, and rheological properties, pathological blood will have different rheological properties than healthy blood [7,8]. By modeling healthy blood, we can establish a baseline that will then allow us to characterize and diagnose pathological blood based on its flow behavior, as was seen in the Moreno paper with high cholesterol [3].

Applying large amplitude oscillatory shear (LAOS) to complex fluids (including blood) induces nonlinear rheological responses, that with proper modeling, can be used to sensitively probe the underlying microstructure and its dynamics. We demonstrate this with published blood steady state and transient data, using a the best simple models [3,4,5,6]. We will first demonstrate the state of blood modeling using simple models comparing and contrasting relevant models and model features. With the best models we will fit to steady state data, and compare predictions of transient, and LAOS data with the published data of Sousa et al. [4] and Bureau et al. [9], to show weaknesses in current best models, and propose potential model improvements. In addition we propose modifications to current transient models that have shown potential to fit these transient experiments with human blood.

References

[1] Merrill, Edward. Rheology of Blood. Physiological Reviews. (1969). USA.

[2] Baskurt OK, Meiselman HJ, Semin Thromb Hemost^. Blood rheology and hemodynamics. Department of Physiology, Akdeniz University Faculty of Medicine, Antalya, Turkey. 2003 Oct;29 (5):435-50.

[3] Moreno, Leonardo and Fausto Caldera, et al. Effect of Cholesterol and Triglycerides Levels on the Rheological Behavior of Human Blood. Korea-Australia Rheology Journal. (2015).

[4] Sousa, P.C. and J Carneiro, et al. Shear Viscosity and Nonlinear Behavior of Whole Blood Under Large Amplitude Oscillatory Shear. Biorheology. (2013).

[5] Apostolidis, A., Armstrong, M., and Beris, A. Modeling of Human Blood Rheology in Transient Shear Flows. University of Delaware. (2014).

[6] Akaike, Hirotugu. A New Look at the Statistical Model of Identification. IEE Transactions of Automatic Control (1974).

[7] Baskurt, Oguz Kerim. Pathophysiological Significance of Blood Rheology. Turk J Med Sci. 33 (2003) 347-355.

[8] Fedosov, Dmitry A., Wenxiao Pan, et al. Predicting human blood viscosity in silico. New York

[9] Bureau et al. Biorheology (1980).