Evaluation of A plasma for incompatible patients

Type-specific whole blood still has a role in the era of low-titer O universal donor transfusion for severe trauma hemorrhage

ABSTRACT

Whole blood can be ABO-type specific (type-specific whole blood (TSWB)) or low-titer O universal donor (low-titer O whole blood (LTOWB)). Having previously used LTOWB, the US Armed Forces Blood Program began using TSWB in 1965 as a method of increasing the donor pool. In contrast to military practice, the Association for the Advancement of Blood and Biotherapies formerly the American association of blood banks (AABB), from its first guidelines in 1958 until 2018, permitted only TSWB. Attempting to reduce time to transfusion, the US military reintroduced LTOWB in the deployed environment in 2015; this practice was endorsed by the AABB in 2018 and is progressively being implemented by military and civilian providers worldwide. Low-titer O whole blood is the only practical solution prehospital. However, there are several reasons to retain the option of TSWB in hospitals with a laboratory. These include (1) as-yet ill-defined risks of immunological complications from ABO-incompatible plasma (even when this has low titers of anti-A and -B), (2) risks of high volumes of LTOWB including published historical advice (based on clinical experience) not to transfuse type-specific blood for 2 to 3 weeks following a substantial LTOWB transfusion, (3) uncertainty as to the optimal definition of "low titer," and (4) expanding the potential donor pool by allowing type-specific transfusion. Several large randomized controlled trials currently underway are comparing LTOWB with component therapy, but none address the question of LTOWB versus TSWB. There are sufficient data to suggest that the additional risks of transfusing LTOWB to non-group O recipients should be avoided by using TSWB as soon as possible. Combined with the advantage of maintaining an adequate supply of blood products in times of high demand, this suggests that retaining TSWB within the civilian and military blood supply system is desirable. TSWB should be preferred when patient blood group is confirmed in facilities with a hematology laboratory, with LTOWB reserved for patients whose blood group is unknown.

Risk of ABO-Incompatible Plasma From Non-ABO-Identical Components

The last several decades have seen significant changes in the approach to resuscitation of bleeding patients. These include the adoption of ABO-incompatible plasma transfusion in the form of group A plasma and/or low titer group O whole blood for trauma patients of unknown ABO group. Studies to date have examined the impact of these practices on patient outcomes and clinical markers of hemolysis in recipients of ABO-incompatible plasma compared to those for whom the plasma is ABO-compatible. Risk for increased mortality and/or overt hemolysis appear to be low among recipients of ABO-incompatible plasma; however, nearly all of studies are retrospective and most have focused only on adult trauma patients so results may not be generalizable to other bleeding patients. Work continues to evaluate the role of various titer thresholds in decreasing hemolytic risk and opportunities remain to improve our understanding of anti-A and anti-B antibody interactions with complement/endothelium and identify strategies to minimize risk.