Shear-induced hemolysis: effects of blood chemistry (including aging in storage) and shearing surfaces.

Rotating disks were used to hemolyze blood under low-stress laminar flow conditions. In the first sequence of tests, kinetic hemolysis curves (KHC) were obtained with polyethylene disks for three well-characterized bloods and repeated over a period of four weeks. Each blood had a KHC with different shape, which maintained its characteristics while aging. Correlations were sought between D6000 (percent of complete hemolysis, after 6000 sec of shear) and D0 (measured before shear) by two means of data analysis, in terms of blood chemistry. It was found that uric acid and very-low-density lipoprotein levels were most useful in predicting the characteristic D6000 vs. D0 relation for each blood, and that glucose levels correlated the rate of aging as measured by hemolysis. Other chemical factors are also displayed in terms of their influence on D0. The second series of tests consisted of comparing the KHC for four disk materials using a fourth blood, then repeating with a fifth blood. Hemolytic rankings of the materials were the same with these two blood, although the KHC shapes differed. The rankings were: polyvinyl chloride greater than Silastic approximately equal to polyethylene greater than polyether urethane, with PVC most hemolytic. In another sequence for examining materials effects, five different bloods were used to compare the hemolytic properties of Teflon, nylon, and polyethylene disks. Although the KHC for the three disks bore different relationships to each other with each different blood, extrapolation of data beyond 6000 sec suggests a ranking of Teflon greater than nylon greater than polyethylene.