In the study by Nascimento and colleagues,1 the patients who received increased plasma and platelet transfusions had greater mortality due to bleeding (22%) than the control group (9%), albeit not statistically significantly so. Nonetheless, it raises the question of whether the plasma and platelet transfusion worsened hemorrhage rather than mitigated it. One possible mechanism is the administration of ABO non-identical plasma and platelets. Preliminary published observational data show that trauma patients receiving ABO non-identical (mismatched) platelets have increased red cell transfusion needs, as do patients who experience serious blood loss during surgery in general.2,3 A possible mechanism is that exposure of platelets and endothelial cells to incompatible anti-A and anti-B antibody impairs platelet function, coagulation and hemostasis.4 That group O individuals have much lower levels of von Willebrand factor than non-O individuals is also well established.
Have the authors considered analyzing their data according to how much ABO incompatible/non-identical plasma or platelet transfusions were given, or the ABO types of the patients? This variable might have contributed to the increased hemorrhagic mortality seen in the recipients of larger amounts of ostensibly hemostatic blood components.
References
- 1.Nascimento B, Callum J, Tien H, et al. Effect of a fixed-ratio (1:1:1) transfusion protocol versus laboratory-results–guided transfusion in patients with severe trauma: a randomized feasibility trial. CMAJ 2013;185:E583–9 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Fialkow LB, Zucchiatti A, Cheng J, et al. ABO nonidentical transfusions and red blood cell usage in blunt trauma patients. Transfusion 2007;47(Suppl): 192A–3A17302762 [Google Scholar]
- 3.Refaai MA, Fialkow LB, Heal JM, et al. An association of ABO mismatched platelet and cryoprecipitate transfusions with increased red cell transfusion needs and mortality in surgical patients. Vox Sang 2011;101:55–60 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Refaai MA, Carter J, Henrichs KF, et al. Alterations of platelet function and clot formation kinetics following in vitro exposure to anti-A and -B antibodies. Transfusion 2013;53:382–93 [DOI] [PMC free article] [PubMed] [Google Scholar]