Leukocyte removal efficiency of cell-washed and unwashed whole blood: an in vitro study

Abstract

Leukocyte filtration of the cardiopulmonary bypass (CPB) perfusate after cardiac surgery has evolved as an important technique to prevent effector functions mediated by activated leukocytes. However, little is known about the filtration efficiency. Therefore, an in vitro study was conducted to define the leukocyte removal rate of a transfusion leukocyte-depletion filter, using cell-washed and unwashed whole porcine blood. In addition, the influence of different cell-washing protocols on the elimination rate of blood cells (leukocytes and platelets) was investigated. Fresh, diluted, pooled, heparinized, porcine blood was processed using either a high-flow (HF, n = 5) or quality-wash (QW, n = 5) protocol on a continuous auto-transfusion system, or was left unprocessed (control n=5). Thereafter, all samples were filtered using a transfusion leukocyte-depletion filter. Blood samples for measurement of hematocrit, white blood cell count, including leukocyte differentiation and platelet count, were taken before and after filtration. To compare the experimental groups, the removal rate was presented as the fraction of leukocytes or platelets removed per plasma volume. Cell washing significantly altered the fraction of leukocytes removed per plasma volume when compared to unprocessed blood (2.07 and 2.36 in the HF and QW groups, respectively, versus 1.34 in the control group, p = 0.008 for both). No statistically significant difference in leukocyte removal rate was observed between the different cell-washing protocols. The leukocyte differential count showed that, during all experiments, the neutrophils were removed most efficiently (99.7%). Overall, significantly more platelets were depleted after cell washing compared to the control group (1.47 and 1.60 in the HF and QW groups, respectively, versus 1.12 in the control group, p =0.008 and 0.032, respectively). Furthermore, the amount of blood that could be filtered using a single pass technique did not significantly differ between the experimental groups. However, a larger variation in the total amount of filtered blood was observed in the unprocessed group (570+/-398 mL) compared to the cell-washed groups (360+/-42 and 430+/-97 mL in the HF and QW groups, respectively). In conclusion, blood processing with an auto-transfusion system significantly enhances the leukocyte and platelet removal efficiency of the transfusion leukocyte-depletion filter that was studied. In particular, neutrophils were efficiently removed.

Impact of intraoperatively salvaged and washed blood on stimulated cytokine release in vitro

“…In our investigation, the processing of the salvaged blood significantly reduced the PLT count compared to venous blood. This is in line with the findings of ten Brinke and colleagues who reported that blood processing with an automatic autotransfusion system significantly enhances the PLT removal. In contrast, Naumenko and coworkers observed a significant increase of the PLTs due to the processing.…”

“…[32][33][34][35] In our investigation, we found an increase in the concentration of the WBCs in the salvaged blood compared to venous blood that was even higher than the increase of the Hct. This was in contrast to other investigations, 36,37 because usually during cell washing some WBCs are lost. However, the observed results in the concentration of WBCs and RBCs in our study might depend on the used continuous autotransfusion system (C.A.T.S., Fresenius).…”

A Novel Centrifugation Method Using a Cell Salvage Device Offers an Alternative to the Use of Leukocyte-Depleting Filters for Autologous Blood Transfusions

“…To compare the two methods and account for this volume difference, we used the final HCT from each method to normalize the data. This correlation has been similarly described in other studies (12). Considering the effect of erythrocyte concentration on leukocyte count when comparing the two methods, no statistically significant difference in leukocyte reduction was found.…”

Cell Salvage in Oncological Surgery, Peripartum Haemorrhage and Trauma

“…The presence of contaminants in recovered blood should be considered as a contraindication (Table 1), but this is controversial with little evidence to support widespread use in such conditions. Filtering and complete washing of red blood cells (RBC) with 0.9% saline [2][3][4] are considered indispensable premises to avoid the incorporation of potentially harmful elements.…”