Blood Group O and ABO Non-Identical Platelet Transfusions Are Associated with Increased Red Cell Utilization in Non-Trauma Surgical Patients.

Abstract

The transfusion of ABO non-identical platelets is an accepted practice, involving infusion of antigen and/or antibody that is ABO incompatible with the recipient. This results in the formation of high molecular weight immune complexes, which could, in theory, adversely affect platelet and coagulation factor function. Studies have demonstrated putative deleterious effects of ABO non-identical transfusions. In cardiac surgery patients receiving ABO non-identical platelets required 50% more red blood cell (RBC) transfusions than those who received only ABO identical platelets (Transfusion 41:790, 2001). Furthermore, blood group O and A patients have genetically determined lower levels of von Willebrand factor (vWF) than B and AB patients (Blood 69:1691, 1987), and might be expected to have more bleeding and require more RBC transfusions. Our institution implemented a protocol of transfusing only ABO identical components in April, 2005. We report here the potential effects of transfusing ABO non-identical platelets, by comparing RBC usage in surgical patients before and after introduction of a protocol of “only ABO identical” transfusions. We also report the role of ABO blood group in red cell usage. Because non-group O trauma patients by necessity receive group O red cells we excluded them from this analysis. Transfusion records for all non-trauma surgical patients receiving any platelet transfusions for one year after April, 2005 were reviewed. Patients receiving only ABO identical platelet transfusions were analyzed by blood groups: B/AB versus O/A. Group B/AB patients (n=72) required a mean of 12.5 +/− 11.7 RBCs, whereas group A/O patients (n=313) required 17.8 +/− 20.5 (p=0.036). These findings are the reverse of the patient populations receiving a mixture of ABO identical and non-identical platelets prior to April, 2005, before the implementation of an “ only ABO identical” transfusion policy. Group B/AB patients, who received more ABO non-identical platelet transfusions than A/O patients (mean 7.5 +/− 11 versus 3.3 +/− 6.2, p=0.0001), required significantly more RBCs (mean 19 +/− 25 versus 13 +/− 13, p=0.0086). Amongst those receiving only ABO identical transfusions group O patients required the largest number of RBCs, (mean 19.6 +/− 24.1), followed by A (16.0 +/− 15.8, p=0.096), B (13.2 +/− 13.1, p=0.041), and AB (11.2 +/− 7.8, p=0.05). One plausible explanation is that blood group O patients have the lowest levels of vWF and other clotting factors, while AB patients have the highest levels (AB > B > A > O). Our data in recipients of ABO identical transfusions confirm findings in the literature that group O patients may be at greater risk of hemorrhage than groups B and AB patients. However, when ABO non-identical platelets are transfused, significantly more bleeding is seen in group AB and B patients than in group O patients. We hypothesize that ABO non-identical transfusions may impair, rather than improve, hemostasis in some patients.RBC Usage (Units) Pre and Post ABO Identical Only PolicyBlood Groups A/OBlood Groups B/ABP-ValuePre-ABO Identical Only Policy13 +/− 1319 +/− 250.0086Post-ABO Identical Only Policy17.8 +/− 20.512.5 +/− 11.70.036