Comparative efficacy of leukocyte removal by blood filters in autologous cell salvage

Background Autotransfusion devices concentrate white blood cells (WBCs) within the washed product that may lead to undesirable clinical effects when reinfused to the patient. This quality improvement project evaluated the leukocyte removal efficacy of three types of salvaged blood filters in autologous cell salvage. Methods Using a prospective observational cohort approach, we evaluated microaggregate, lipid-reducing, and leukocyte-reducing salvaged blood filters in adult patients undergoing surgery with autologous cell salvage. Filters were evaluated one after another, with samples of processed autologous blood collected prior to filtration and again after 30 mL had passed through each type of filter to allow for direct comparison of each filter’s effects on WBC concentrations. Results Salvaged blood samples were collected from 35 patients. Median pre-filtration WBC count was 9.8 [6.8-13.3] × 10 9 /L, being reduced to 9.3 [6.6-12.6] × 10 9 /L after microaggregate filtration (1.7 [−0.6-4.6]% removal), 0.8 [0.5-2.5] × 10 9 /L after lipid filtration (89.7 [83.3-93.9]% removal), and 0.0 [0.0-0.0] × 10 9 /L after leukocyte filtration (100 [100-100]% removal). The microaggregate filter achieved significantly less WBC reduction than both the leukocyte-reducing filter ( p < 0.0001) and lipid-reducing filter ( p < 0.0001). There was no significant difference observed between the leukocyte-reducing and lipid-reducing filters ( p = 0.3124). Conclusions Leukocyte- and lipid-reducing filters were effective at reducing WBCs from processed autologous blood by nearly 10-fold, while microaggregate filters were significantly less effective at removing leukocytes. Use of leukocyte- or lipid-reducing filters minimizes the number of activated WBCs reinfused to the patient during autologous cell salvage.