Untersuchungen zur Blutschädigung durch laminare Strömung im Couette-System

Blood damage of artificial systems within the circulatory system still remains a major problem despite of enormous research activities in this area. Forces acting on blood corpuscles due to non physiological flow conditions, partially in combination with artificial surfaces, are considered as main factors of blood damage. The level of blood damage depends on the magnitude of stresses as well as on the exposure time of blood corpuscles to these stresses. Within the scope of this work flow induced damage of red blood cells by flow forces of exactly defined magnitude and duration, characteristic for artificial systems, is studied. For this purpose a shear device with simple laminar flow conditions has been developed and validated with respect to defined damage conditions and negligible secondary damage effects. The tests were performed with porcine blood. The results are discussed with regard to well known experimental data. Theoretical models of red blood cell damage are examined and several approaches for the characterization of blood damage are compared. Possibilities and limitations of damage modeling by computational fluid dynamics are pointed out and the damage by shear device flow is modeled as an example. Finally, possibilities to incorporate time varying shear loads are described