Comparative Evaluation of New Fine-screen Filters

Abstract
Fine-screen filters were studied in a simulated clinical situation wherein 10 units of outdated concentrated erythrocytes were rapidly transfused per filter to determine flow rates and effectivenesses of debris removal. Preliminary studies to evaluate flow rates with outdated whole blood indicated that the Bentley PFF-100, Fenwal 4C9003, and Biotest MF-10 fine-screen filters allowed flow rates sufficient to justify further detailed testing. For comparative purposes, the filter the authors have used clinically, the Pall Ultipor 40-.mu.m filter, was studied again. As many as 10 units of outdated, concentrated erythrocytes (hematocrits 75-85%) were infused through each of the fine-screen filters at 300 torr pressure. All filters (except 1 of 5 Pall filters) accepted all 10 units. The Bentley PFF-100 filter allowed the highest flow rates, so that the 10th unit of erythrocytes required 5 .+-. 3 min to pass the filter. The Biotest MF-10, Bentley PFF-100 and Fenwal 4C9003 filters retained more debris/g erythrocytes, decreased screen filtration pressure, and eliminated more particulate matter (as determined by Coulter counter testing) than did the Pall Ultipor filter. When 3 or more units of blood are transfused, any of the 4 filters tested is cost-effective when compared with the current 170-.mu.m standard transfusion filter.