title: The effect of shear, specific surface, and air interface on the development of blood emboli and hemolysis.
abstract: Heparinized dog blood was exposed to shear and foreign surfaces in conicylindrical test cells. The cells were injection molded from polycarbonate and were filled using a technique that avoided contact of the blood with air. Particulate-matter formation was measured and was found to be dominated by the surface-to-blood-volume ratio and to be independent of shear rate. Hemolysis was also measured and was found to vary linearly with shear rate and to increase with increasing surface-to-blood volume ratio. Thus, at low shear rates and high specific surface conditions, the degree of hemolysis was found to be minimal while particulate-matter formation was high. The results suggest that the safety of extracoporeal perfusion procedures cannot be inferred from hemolysis measurements alone. In one series of tests, a gas-blood interface was generated at a rate equivalent to the rate of surface renewal in conventional disc oxygenators. The gas-blood interface failed to contribute significantly to the damage indices, which suggests that the apparent superiority of membrane oxygenators may be a result of factors other than the absence of a blood-gas interface.
mesh_terms: D001696:Biomechanical Phenomena; D001769:Blood / Q000503:physiopathology*; D004617:Embolism / Q000503:physiopathology*; D005112:Extracorporeal Circulation / Q000009:adverse effects*; D006461:Hemolysis; D006801:Humans; D066298:In Vitro Techniques; D010107:Oxygenators, Membrane