Filters in autologous blood retransfusion systems affect the amount of blood cells retransfused in total knee arthroplasty: a pilot study

A pilot study was undertaken to evaluate whether filters integrated in postoperative retransfusion systems affect the amount of blood cells retransfused after total knee arthroplasty. Twenty-two consecutive patients received either the Donor retransfusion system (n=12 patients) or the Bellovac ABT retransfusion system (n=10). Both systems differ with respect to the type of filter, a Pall Lipiguard filter and a Sangopur filter, respectively. At the beginning of the retransfusion, blood samples were taken before and after the filter. The filter of the Donor system significantly decreased the amount of leukocytes and erythrocytes, whereas the filter of the Bellovac system did not. As a result the haemoglobin level of retransfused blood with the Donor system was significantly lower than with the Bellovac system. It can be concluded that the type of filter integrated in two postoperative autologous blood retransfusion systems significantly affected the amount of blood cells retransfused in patients undergoing total knee arthroplasty.