Microrheology of filtered autotransfusion drain blood with and without leukocyte reduction

Autotransfusion of filtered knee drain blood (FKDB) is frequently practised in orthopaedic surgery, but questioned because it contains inflammatory cy tokines, contaminants from lysed blood cells, debris and chemicals from the wound. We have studied the microrheology (5 mu m pore filtration) of FKDB (n = 23) with versus without the addition of a leukocyte reducing filter (L RF) in line with the drain. As expected the whole blood clogging was reduce d (p < 0.01) due to the lowered leukocyte number by the LRF. FKDB plasma co ntains clogging particles of unknown origin. With the LRF the increased pla sma clogging was reduced (p approximate to 0.05). With resuspended erythroc ytes there was an increase in clogging rate in FKDB at 24 hours. This incre ase was abolished with the addition of the LRF which may indicate that the erythrocyte trauma results from the incubation together with leukocytes in the drain container. There is a potential for further improvement of the fi lters in autotransfusion drains.