Bedside Allogeneic Erythrocyte Washing with a Cell Saver to Remove Cytokines, Chemokines, and Cell-derived Microvesicles

Abstract

Background Removal of cytokines, chemokines, and microvesicles from the supernatant of allogeneic erythrocytes may help mitigate adverse transfusion reactions. Blood bank–based washing procedures present logistical difficulties; therefore, we tested the hypothesis that on-demand bedside washing of allogeneic erythrocyte units is capable of removing soluble factors and is feasible in a clinical setting. Methods There were in vitro and prospective, observation cohort components to this a priori planned substudy evaluating bedside allogeneic erythrocyte washing, with a cell saver, during cardiac surgery. Laboratory data were collected from the first 75 washed units given to a subset of patients nested in the intervention arm of a parent clinical trial. Paired pre- and postwash samples from the blood unit bags were centrifuged. The supernatant was aspirated and frozen at –70°C, then batch-tested for cell-derived microvesicles, soluble CD40 ligand, chemokine ligand 5, and neutral lipids (all previously associated with transfusion reactions) and cell-free hemoglobin (possibly increased by washing). From the entire cohort randomized to the intervention arm of the trial, bedside washing was defined as feasible if at least 75% of prescribed units were washed per protocol. Results Paired data were available for 74 units. Washing reduced soluble CD40 ligand (median [interquartile range]; from 143 [1 to 338] ng/ml to zero), chemokine ligand 5 (from 1,314 [715 to 2,551] to 305 [179 to 488] ng/ml), and microvesicle numbers (from 6.90 [4.10 to 20.0] to 0.83 [0.33 to 2.80] × 106), while cell-free hemoglobin concentration increased from 72.6 (53.6 to 171.6) mg/dl to 210.5 (126.6 to 479.6) mg/dl (P < 0.0001 for each). There was no effect on neutral lipids. Bedside washing was determined as feasible for 80 of 81 patients (99%); overall, 293 of 314 (93%) units were washed per protocol. Conclusions Bedside erythrocyte washing was clinically feasible and greatly reduced concentrations of soluble factors thought to be associated with transfusion-related adverse reactions, increasing concentrations of cell-free hemoglobin while maintaining acceptable (less than 0.8%) hemolysis. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Blood Transfusion Predicts Prolonged Mechanical Ventilation in Acute Stanford Type A Aortic Dissection Undergoing Total Aortic Arch Replacement

“…It may be a more direct way to avoid using the long-stored red cells in a long and traumatic surgery (50). We also considered removing excessive hemolysis products and anticoagulants by the purification system before transfusion to reduce post-transfusion complications (51,52). More targeted research is needed to facilitate the development of guidelines.…”

Intraoperative Cell-Saver Caused More Autologous Salvage Hemolysis in a Hereditary Spherocytosis Patient Than in a Normal Erythrocyte Patient

“…For the packed or stored allogeneic RBCs, a mean cell-free hemoglobin concentration could increase from 72.6 mg/dl to 210.5 mg/dl after washing using the CS system. Despite the significantly increased post-wash cell-free hemoglobin, the washed allogeneic salvage was estimated to result in a mild and acceptable increase (3–5 mg/dl) in recipients’ cell-free hemoglobin ( Welsby et al, 2021 ). For the autologous salvage in our report, much lower cell-free hemoglobin concentrations were found in either the HS (82.6 mg/dl) or normal erythrocytic (57.9 mg/dl) patient’s post-wash sample than in the washed allogeneic salvage, so neither patient manifested significant hemolysis after receiving the autologous salvage.…”

“…The Cell Saver ® (CS) system is designed for autologous blood salvage with the removal of broken blood cells and platelets, reduction of cytokines and chemokines, and increased hemolysis with an acceptable concentration of cell-free hemoglobin ( Welsby et al, 2021 ). The quality of salvaged RBCs from the CS system after washing, centrifugation, and pump rolling, however, remains unclear, with the fragility of salvaged RBCs might be increased under some conditions ( Chung et al, 2019 ), which could lead to more hemolysis after the salvaged RBCs are transfused back to the patient as osmotic fragility is an important determinant in the severity of hemolysis.…”

Red cell extracellular vesicles and coagulation activation pathways

“…Washing of PRBCs is indicated in severe or recurrent allergic transfusion reactions, severe potassium sensitivity, and potentially in other adverse events of blood transfusion [22]. sREVs significantly decreased up to 2 h after washing PRBCs using an automated cell saver with a low centrifugal force [23]. sREVs also decreased in stored murine RBCs after mid-storage washing at 7 days with an additional 7 day storage in AS1 compared with 14 days of storage without washing [24].…”