Abstract
Although albumin (Alb) and free-hemoglobin (F-Hb) have almost the same molecular weight, their configurations are slightly different. The new EVAL Filter, 1A with membrane pores of intermediate diameter between Alb and F-Hb selectively removes F-Hb, an excellent characteristic not found in the conventional devices: The sieving coefficients (SC) of Alb and F-Hb were 17.6±6.4% and 36.2±7.2%, the SC of F-Hb being about 2 times higher than that of Alb. The EVAL Filter 1A was clinically employed in 30 cases immediately after cardiopulmonary bypass (CPB), with a subsequent increase in the hematocrit level from 25.7±5.0% to 39.5±6.3%. The total plasma protein was also effectively concentrated from 3.8±1.0g/dl to 6.6±1.7g/dl. The new EVAL Filter also proved to be very useful when emproyed during CPB, especially in one case of severe hemolysis complicated by renal insufficiency, where 5, 960ml of excess water and a total of 1, 907mg of F-Hb could be removed in 146 minutes. Electron microscopically, the membrane of the EVAL Filter revealed an intricate and labyrinthine structure with pores of non-uniform size and configuration. Such a special structure and adequate pore size of the membrane seemed to make selective filtration possible on account of the slight physical differences between the Alb and F-Hb molecules.
