Associate Professor; Associate Medical Director University of California San Diego San Diego, California, United States
Background/Case Studies: Implementation of low-titer group O whole blood (LTOWB) has increased significantly in recent years. Among the considerations of a LTOWB program are wastage and the risk of anti-D alloimmunization in RhD-negative recipients. Our adult level 1 trauma center, which treats approximately 3,000 trauma patients annually, introduced LTOWB in 2020. All LTOWB units are RhD-positive and may only be transfused to trauma patients at the discretion of the trauma attending physician. Usage is limited to four LTOWB units per patient. This two-year retrospective review analyzed LTOWB usage, wastage, and recipient characteristics.
Study
Design/Methods: LTOWB disposition data were reviewed from 1/1/2021 to 12/31/2022. Recipient data, including sex, ABO/Rh type, number of LTOWB and other blood component units received were recorded. Antibody screens performed at least 28 days after the index LTOWB transfusion(s) in RhD-negative recipients were reviewed, when available. This study was determined to be exempt from Institutional Review Board requirements.
Results/Findings: Over the two-year study period, 307 units of LTOWB were transfused to 114 unique recipients, averaging 2.7 units per patient. The average LTOWB usage and wastage volumes per month were 12.8 and 2.6 units respectively, (Figure 1). Approximately 80% of the LTOWB recipients were male, 20% were female, and one recipient’s sex was not determined. Recipient blood types were 40% O, 29% A, 11% B, 2% AB, and 18% unknown. Seventy-two percent of recipients were RhD-positive, 9% were RhD-negative, 18% had an unknown RhD status, and 2% had indeterminate RhD typing. Of the 32 patients who were RhD-negative, -unknown, or -indeterminate, 12 (38%) survived through discharge. Two of these patients had follow-up antibody screens performed, and neither developed anti-D antibodies. In addition to LTOWB, 67 recipients (59%) received blood components and were transfused a combined total of 603 units of packed red blood cells, 494 units of fresh frozen plasma, 78 units of apheresis platelets, and 30 pools of cryoprecipitate (mean 9.0, 7.4, 1.2, and 0.4 per patient, respectively). Conclusions: Implementing and maintaining a LTOWB program is feasible, and utilizing LTOWB exclusively in a trauma setting facilitates inventory management. This review confirmed that the vast majority of LTOWB recipients were male and RhD-positive. A considerable percentage of recipients had an unknown blood type and/or RhD type. Most of the type-unknown patients expired prior to blood typing. No RhD-negative recipients of LTOWB with follow-up antibody screening developed anti-D antibodies. Since LTOWB use and waste varied without any evident seasonal patterns, continued assessment may encourage consideration of manufacturing RBC units from unused LTOWB. Future analyses will assess whether the use of LTOWB affects mortality or massive transfusion rates.
Importance of research: This study provides demand and wastage information for similar sized trauma programs that are considering implementing whole blood. The data from this study adds to the body of literature about LTOWB recipient characteristics, which can inform discussions about risk profiles and institutional policies.
