Use of Uncrossmatched Erythrocytes in Emergency Bleeding Situations

UNCROSSMATCHED erythrocytes are a lifesaving bridge between a hemorrhaging patient of unknown ABO blood group not receiving erythrocyte transfusions and the provision of crossmatched units. Unless the recipient ’s ABO group is known, group O uncrossmatched erythrocytes will be issued, which are compatible with the preformed anti-A and/or anti-B (hemagglutinins) that are present in all recipients who are not blood group AB (table 1). Issuing group O erythrocyte units prevents acute, intravascular hemolytic reactions from occurring when uncrossmatched erythrocytes are transfused to a recipient of unknown ABO group. An acute (occurring within 24  h of the transfusion) intravascular reaction occurs when complement-fixing antibodies, such as the naturally occurring IgM isotype anti-A and/or anti-B found in all recipients who are not blood group AB, bind to their target antigen and fix complement, thereby causing the destruction of the eryth rocytes inside the vascular system.1 These reactions can be life threatening because of the nature of the substances released from the lysed erythrocytes. In contrast, an extravascular hemolytic reaction is caused by IgG antibodies and tends to be less life threatening because the erythrocytes are destroyed in a contained manner in the liver and spleen, thereby not releasing intra-erythrocyte substances directly into the bloodstream. Thus, uncrossmatched erythrocytes can be administered to any patient with severe anemia or acute hemorrhage ...

Source: Anesthesiology - February 14, 2018 Category: Anesthesiology Source Type: research