Perception of risk in massive transfusion as it relates to fetal outcomes: A survey of surgeons and nurses at one American trauma center

Evolution of whole blood trauma resuscitation in childbearing age females: practice patterns and trends

Background

The use of low titer group O whole blood (LTOWB) for resuscitation of patients with traumatic hemorrhage is becoming increasingly common. Practices regarding the administration of RhD-positive LTOWB to childbearing age females (CBAFs) vary between institutions due to concerns about RhD alloimmunization. This study examined practices related to LTOWB transfusion as they pertain to age and sex.

Methods

This was a secondary analysis of the Shock, Whole blood, and Assessment of TBI (traumatic brain injury) trial, a prospective, multicenter observational cohort study where outcomes following LTOWB transfusion were analyzed at seven level 1 trauma centers between 2018 and 2021, as well as a survey on transfusion practices at these centers conducted in 2023. The proportion of patients who received LTOWB or components was examined over the course of the study and grouped by age and sex, and the RhD group of injured CBAFs was documented.

Results

A total of 1046 patients were evaluated: 130 females aged <50 years (CBAFs), 77 females aged ≥50 years; 661 males aged <50 years, and 178 males aged ≥50 years. Among them, 26.2% of CBAFs received RhD-positive LTOWB, whereas 57.1%-66.3% of other sex/age groups received LTOWB. The proportion of CBAFs who received LTOWB increased significantly throughout the 4 years of this study. Except for older women in years 2 and 4, CBAFs were significantly less likely to receive LTOWB than all other groups for the study period and individual years. Among the 33 CBAFs who received LTOWB and for whom an RhD type was available, 4/33 (12.1%) were RhD-negative, while 9/95 (9.5%) CBAFs who received component therapy were RhD-negative. RhD blood product selection practices varied considerably between institutions.

Conclusions

Many institutions transfused LTOWB to CBAFs. Policies regarding RhD product selection varied. Of the total cohort, the proportion of RhD-negative CBAFs who received LTOWB increased over time but remained lower than all other groups.

Level of evidence

3.

RhD-Alloimmunization in Adult and Pediatric Trauma Patients

The actual risk of providing RhD-positive units to RhD-negative recipients remains debatable. There is no standard of care in the United States (US) to guide transfusion decisions regarding RhD type for patients with an unknown blood type, except for women of childbearing age and neonates. The risk of alloantibody formation by an RhD-negative patient exposed to RhD-positive blood is reported to be from 3% to 70%. Due to such wide variations, this review was undertaken to determine the prevalence of anti-D alloimmunization in trauma patients who are RhD-negative and were transfused RhD-positive blood products. This study used the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA) approach to answer the question, "In trauma patients who were transfused blood, what is the prevalence of alloimmunization to the D-antigen?" The review included all published articles through April 3, 2022 in databases. Articles published after the search period found by the authors were added to the manuscript if they addressed the primary question and there was unanimous consensus. There were 1683 full-text articles that met the search criteria, with 19 studies meeting eligibility criteria. In addition, 57 references were added after the search period had closed. The incidence of anti-D alloimmunization in adult trauma patients receiving whole blood varied from 7.8% to 42.7%. In contrast, incidence varied in patients receiving red blood cells (RBCs), from 0 to 94%, depending on number of categories analyzed. Anti-D alloimmunization with platelet transfusions varied from 0% to 19%. The alloimmunization rate increased with age and was detected only in children older than 5 years. Recent guidelines recommend the administration of Rh immune globulin (RhIG) to all traumatically injured patients who are both RhD-negative and pregnant. However, there is no specific guidance focused on the RhD-negative patient, pregnant or nonpregnant, and who have received RhD-positive red blood cells (RBC) and platelets. While numerous studies have attempted to evaluate the frequency of RhD alloimmunization rate in trauma settings, emerging data suggests that many factors affect this phenomenon. Additionally, the role of RhIG administration in cases of RhD-incompatible transfusions within the trauma setting adds complexity. As our trajectory propels us towards precision medicine and tailored transfusion practices, gaining a big data approach becomes indispensable.

Estimating the risks of prehospital transfusion of D-positive whole blood to trauma patients who are bleeding in England

Background and Objectives

D‐negative red cells are transfused to D‐negative females of childbearing potential (CBP) to prevent haemolytic disease of the foetus and newborn (HDFN). Transfusion of low‐titre group O whole blood (LTOWB) prehospital is gaining interest, to potentially improve clinical outcomes and for logistical benefits compared to standard of care. Enhanced donor selection requirements and reduced shelf‐life of LTOWB compared to red cells makes the provision of this product challenging.

Materials and Methods

A universal policy change to the use of D‐positive LTOWB across England was modelled in terms of risk of three specific harms occurring: risk of haemolytic transfusion reaction now or in the future, and the risk of HDFN in future pregnancies for all recipients or D‐negative females of CBP.

Results

The risk of any of the three harms occurring for all recipients was 1:14 × 10³ transfusions (credibility interval [CI] 56 × 10²–42 × 10³) while for females of CBP it was 1:520 transfusions (CI 250–1700). The latter was dominated by HDFN risk, which would be expected to occur once every 5.7 years (CI 2.6–22.5). We estimated that a survival benefit of ≥1% using LTOWB would result in more life‐years gained than lost if D‐positive units were transfused exclusively. These risks would be lower, if D‐positive blood were only transfused when D‐negative units are unavailable.

Conclusion

These data suggest that the risk of transfusing RhD‐positive blood is low in the prehospital setting and must be balanced against its potential benefits.