Effect of wall hardness on hemolysis

One of the major problems for artificial organs to develop and to improve i s the reduction of hemolysis. The optimum designing of less hemolysis artif icial organs is achieved through computational analysis and flow visualizat ion techniques. However, it is impossible to know the quantitative relation between hemolysis and these analytic data. Thus, in vitro studies were per formed to estimate these devices on hemolysis because there is no standard for designing these devices with less hemolysis. Therefore, it is essential to reveal the relation between blood flow behaviors and hemolysis. Previou s studies reported that hemolysis was caused by a combination of physical f actors. In particular, shear stress, pressure, and other fluid dynamical ef fects were shown to induce hemolysis. In another fluid dynamical experiment reported, the collision flow against the sanded wall was considered the mo st important factor that directly effected blood damage, which led to hemol ysis. The blood flow impact of the collision against the wall effected seri ous damage to red blood cells. The objective of this study was to point out the relationship between physical farce (pressure) in collision flow and h emolysis. In vitro tests using bovine blood and a circulation model that in cluded a jet flow that collides against a wall were conducted. In these tes ts, we changed the material of the wall by replacing silicone rubber of var ious thicknesses. The thickness of the silicons rubber is inversely proport ional to its hardness. The results show that the increasing rate of hemolys is was lower when the surface was coated by silicons rubber. In conclusion, we considered that it is possible to reduce hemolysis by adjusting the har dness of the material and contacted blood flow.