Background: Removal of leukocytes (LR) has been shown to eliminate or attenuate many of the adverse effects of transfusion in experimental animals and humans.Hypothesis/Objectives: Transfusion of stored packed red blood cells (pRBCs) is associated with an inflammatory response in dogs and prestorage LR attenuates the inflammatory response.Animals: Thirteen random-source, clinically healthy, medium and large breed dogs. Methods: Experimental study. On day 0, animals were examined and baseline blood samples were collected for analysis. Whole blood was then collected for processing with and without LR, and stored as pRBC. Twenty-one days later, stored pRBCs were transfused back to the donor. Blood samples were collected before and 1 and 3 days after transfusion.Results: In the dogs that received non-LR pRBCs (n 5 6) there was a significant increase from baseline in white blood cell count from a mean (SD) of 8.20 (2.74) to 13.95 (4.60) Â 10 3 cells/mL (P o .001) and in segmented neutrophil count from a mean (SD) of 5.76 (2.70) to 11.91 (4.71) Â 10 3 cells/mL (P o .001). There were also significant increases in fibrinogen from a mean (SD) of 129.7 (24.2) to 268.6 (46.7) mg/dL (P o .001) and C-reactive protein from a mean (SD) of 1.9 (2.1) to 78.3 (39.3) mg/mL (P o .001). There was no significant increase from baseline in any of the markers in the dogs that received LR pRBC (n 5 5).Conclusions and Clinical Importance: There is a profound inflammatory response to transfusion in normal dogs, which is eliminated by LR of the pRBC units.

For TEM of canine blood samples, coagulation time was primarily a function of coagulation factor concentrations, whereas other variables were dependent on platelet and fibrinogen concentrations. Sample Hct strongly influenced the results of TEM, likely because RBCs act as a diluent for plasma coagulation factors. Thromboelastometry appeared to be affected by abnormalities of coagulation factors, platelet concentrations, and RBC mass. In samples from anemic patients, results of TEM indicative of hypercoagulability may be artifactual because of low RBC mass.

The objective of the present study was to systematically evaluate the impact of methodology on thromboelastometry with canine whole blood. Thromboelastometry was performed on citrated blood using a variety of combinations of clotting activators [ex-tem (tissue factor or TF), in-tem (ellagic acid), diluted TF from Innovin, or Ca (recalcification only)] and storage times. Thromboelastometry was also performed using diluted TF from Innovin on blood collected into a contact inhibitor. Ex-vivo contact activation was compared between canine and human blood. Clotting activator had a marked impact on coagulation time, a minor impact on alpha angle, and no impact on clot formation time or maximum clot firmness. When ex-tem or in-tem was the clotting activator, sample storage up to 30 min did not affect results. With diluted TF from Innovin or Ca, sample storage was associated with the development of increased coagulability (as indicated by shorter coagulation time and clot formation time and higher alpha angle) due to ex-vivo contact activation. Canine blood underwent markedly more ex-vivo contact activation than did human blood. Canine blood undergoes significant ex-vivo contact activation during and after collection, which influences thromboelastometry results when a weak clotting activator (such as low TF or recalcification) is used. Thromboelastometry with a strong activator (such as ex-tem or in-tem) is less influenced by ex-vivo changes, and, therefore, likely to be more reflective of in-vivo hemostatic capabilities and to provide consistently interpretable and comparable results.

This study demonstrated a marked, storage time-dependent accumulation of IL-8 in canine erythrocyte concentrates. Prestorage LR attenuated the accumulation of IL-8. This chemokine may contribute to the proinflammatory effects of transfusion of stored erythrocyte concentrates.

There was marked formation of phosphatidylserine-expressing MPs during storage beyond 7 days in canine RBC concentrates. Prestorage LR attenuated the generation of MPs.