An evaluation of several blood transfusion filters

Several blood transfusion filters designed to remove microemboli were evaluated for filtration and flow characteristics, as well as for hemolysis and for release of particulate debris from the filter. The Dacron wool filter, a depth filter, was superior at removing microemboli measured with an electronic particle size analyzer. A 25 micrometer pore mesh filter was least effective at removing microemboli from stored blood, but demonstrated the most favorable flow rates and induced no apparent red blood cell destruction during filtration. In general, filter efficiency and filter induced hemolysis correlated inversely with flow rate. No filter tested released significant quantities of particulate debris when compared with unfiltered isotonic saline.