The risk to future pregnancies of transfusing Rh(D)-negative females of childbearing potential with Rh(D)-positive red blood cells during trauma resuscitation is dependent on their age at transfusion

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.

Receipt of RhD-positive whole blood for life-threatening bleeding in female children: A survey in alloimmunized mothers regarding minimum acceptable survival benefit relative to risk of maternal alloimmunization to anti-D

BACKGROUND

Low-titer group O whole blood (LTOWB) for treatment of hemorrhagic shock sometimes necessitates transfusion of RhD-positive units due to short supply of RhD-negative LTOWB. Practitioners must choose between using RhD-positive LTOWB when RhD-negative is unavailable against the risk to a female of childbearing potential of becoming RhD-alloimmunized, risking hemolytic disease of the fetus and newborn (HDFN) in future children, or using component therapy with RhD-negative red cells. This survey asked females with a history of red blood cell (RBC) alloimmunization about their risk tolerance of RhD alloimmunization compared to the potential for improved survival following transfusion of RhD-positive blood for an injured RhD negative female child.

STUDY DESIGN AND METHODS

A survey was administered to RBC alloimmunized mothers. Respondents were eligible if they were living in the United States with at least one red cell antibody known to cause HDFN and if they had at least one RBC alloimmunized pregnancy.

RESULTS

Responses from 107 RBC alloimmmunized females were analyzed. There were 32/107 (30%) with a history of severe HDFN; 12/107 (11%) had a history of fetal or neonatal loss due to HDFN. The median (interquartile range) absolute improvement in survival at which the respondents would accept RhD-positive transfusions for a female child was 4% (1%-14%). This was not different between females with and without a history of severe or fatal HDFN (p = .08 and 0.38, respectively).

CONCLUSION

Alloimmunized mothers would accept the risk of D-alloimmunization in a RhD-negative female child for improved survival in cases of life-threatening bleeding.

Ethical considerations in the use of RhD-positive blood products in trauma

BACKGROUND

Prehospital and early in-hospital use of low titer group O whole blood (LTOWB) for life-threatening bleeding has been independently associated with improved survival compared to component therapy. However, when RhD-positive blood products are administered to RhD-negative females of childbearing potential (FCP), there is a small future risk of hemolytic disease of the fetus and newborn (HDFN). This raises important ethical questions that must be explored in order to justify the use of RhD-positive blood products, including LTOWB, both in clinical practice and research.

METHODS

This essay explores the ethical challenges related to RhD-positive blood product administration to RhD-negative or RhD-unknown FCPs as a first-line resuscitation fluid in the trauma setting. These ethical issues include: issues related to decision-making, ethical analysis based on the doctrine of double effect (DDE), and attendant obligations incurred by hospitals that administer RhD-positive blood to FCPs.

RESULTS

Ethical analysis through the use of the DDE demonstrates that utilization of RhD-positive blood products, including LTOWB, in the early resuscitation of FCPs is an ethically appropriate approach. By accepting the risk of HDFN, hospitals generate obligations to promote blood donation, evaluate for alloimmunization and counsel patients on the future risk of HDFN, and maintain an understanding of the ethical rationale for RhD-positive blood transfusion.

Low titer group O whole blood and risk of RhD alloimmunization: Rationale for use in Finland

BACKGROUND

Prehospital low-titer group O whole blood (LTOWB) used for patients with life-threatening hemorrhage is often RhD positive. The most important complication following RhD alloimmunization is hemolytic disease of the fetus and newborn (HDFN). Preceding clinical use of RhD positive LTOWB, we estimated the risk of HDFN due to LTOWB prehospital transfusion in the Finnish population.

STUDY DESIGN AND METHODS

We collected data on prehospital transfusions in Tampere and Helsinki University Hospital areas. Using the mean of reported alloimmunization rates in trauma studies (24%) and a higher reported rate representing trauma patients of 13-50 years old (42.7%), we estimated the risk of HDFN and extrapolated it to the whole of Finland.

RESULTS

We estimated that in Finland, with the current prehospital transfusion rate we would see 1-3 cases of severe HDFN due to prehospital LTOWB transfusions every 10 years, and fetal death due to HDFN caused by LTOWB transfusion less than once in 100 years.

DISCUSSION

The estimated risk of serious HDFN due to prehospital LTOWB transfusion in the Finnish population is similar to previous estimates. As Finland routinely screens expectant mothers for red blood cell antibodies and as the contemporary treatment of HDFN is very effective, we support the prehospital use of RhD positive LTOWB in all patient groups.

Maternal and child life years gained by transfusing low titer group O whole blood in trauma: A computer simulation

BACKGROUND

Using low titer group O whole blood (LTOWB) is increasingly popular for resuscitating trauma patients. LTOWB is often RhD-positive, which might cause D-alloimmunization and hemolytic disease of the fetus and newborn (HDFN) if transfused to RhD-negative females of childbearing potential (FCP). This simulation determined the number of life years gained by the FCP and her future children if she was resuscitated with LTOWB compared with conventional component therapy (CCT).

METHODS

The model simulated 500,000 injured FCPs of each age between 0 and 49 years with LTOWB mortality relative reductions (MRRs) compared with components between 0.1% and 25%. For each surviving FCP, number of life years gained was calculated using her age at injury and average life expectancy for American women. The number of expected future pregnancies for FCPs that did not survive was also based on her age at injury; each future child was assigned the maximum lifespan unless they suffered perinatal mortality or serious neurological events from HDFN.

RESULTS

The LTOWB group with an MRR 25% compared with CCT had the largest total life years gained. The point of equivalence for RhD-positive LTOWB compared to CCT, where life years lost due to severe HDFN was equivalent to life years gained due to FCP survival/future childbearing, occurred at an MRR of approximately 0.1%.

CONCLUSION

In this model, RhD-positive LTOWB resulted in substantial gains in maternal and child life years compared with CCT. A >0.1% relative mortality reduction from LTOWB offset the life years lost to HDFN mortality and severe neurological events.

Implementation of a prehospital whole blood program: Lessons learned

Early blood administration by Emergency Medical Services (EMS) to patients suffering from hemorrhagic shock improves outcomes. Prehospital blood programs represent an invaluable resuscitation capability that directly addresses hemorrhagic shock and mitigates subsequent multiple organ dysfunction syndrome. Prehospital blood programs must be thoughtfully planned, have multiple safeguards, ensure adequate training and credentialing processes, and be responsible stewards of blood resources. According to the 2022 best practices model by Yazer et al, the four key pillars of a successful prehospital program include the following: (1) the rationale for the use and a description of blood products that can be transfused in the prehospital setting, (2) storage of blood products outside the hospital blood bank and how to move them to the patient in the prehospital setting, (3) prehospital transfusion criteria and administration personnel, and (4) documentation of prehospital transfusion and handover to the hospital team.  This concepts paper describes our operational experience using these four pillars to make Maryland's inaugural prehospital ground-based low-titer O-positive whole blood program successful. These lessons learned may inform other EMS systems as they establish prehospital blood programs to help improve outcomes and enhance mass casualty response.

Contemporary management of major haemorrhage in critical care

Haemorrhagic shock is frequent in critical care settings and responsible for a high mortality rate due to multiple organ dysfunction and coagulopathy. The management of critically ill patients with bleeding and shock is complex, and treatment of these patients must be rapid and definitive. The administration of large volumes of blood components leads to major physiological alterations which must be mitigated during and after bleeding. Early recognition of bleeding and coagulopathy, understanding the underlying pathophysiology related to specific disease states, and the development of individualised management protocols are important for optimal outcomes. This review describes the contemporary understanding of the pathophysiology of various types of coagulopathic bleeding; the diagnosis and management of critically ill bleeding patients, including major haemorrhage protocols and post-transfusion management; and finally highlights recent areas of opportunity to better understand optimal management strategies for managing bleeding in the intensive care unit (ICU).

Another piece of the hemolytic disease of the fetus and newborn puzzle after RhD-positive transfusion in trauma resuscitation: the proportion of pregnant women who produce high titer anti-D

Background

After the transfusion of RhD-positive red blood cell (RBC)-containing products to an RhD-negative woman of childbearing potential (WCP) during trauma resuscitation, there are several events that must occur for that WCP to have a future pregnancy affected by hemolytic disease of the fetus and newborn (HDFN). This study identified and quantitated the frequency of a novel event in the sequence from RhD-positive transfusion during trauma resuscitation to an HDFN outcome, that is, the development of a high titer anti-D among women who were D-alloimmunized.

Methods

The transfusion service records at one maternity hospital were searched to locate all anti-D titers that had been performed on pregnant women between 1996 and 2022. The highest titer score during each pregnancy was recorded for this study. The critical titer threshold at this institution was ≥16. Passive anti-D caused by Rh immunoglobulin were excluded from analysis.

Results

There were 97 pregnancies in 85 patients who had an immune-stimulated anti-D; in 60 of 97 (62%) pregnancies, the highest titer score was ≥16. There were 12 patients who had titers performed in two pregnancies during the study period; the correlation between the maximum titer in each pregnancy was not statistically significant (Spearman rank correlation r=0.42, p=0.17).

Conclusion

In this single center study, 62% of D-alloimmunized pregnant women had a high titer antibody. When considering all of the events that must occur for HDFN to happen, the rate of perinatal mortality was calculated to be 0.04% and the rate of perinatal death or serious adverse event from HDFN was 0.24%.

Not as "D"eadly as once thought - the risk of D-alloimmunization and hemolytic disease of the fetus and newborn following RhD-positive transfusion in trauma

The use of blood products to resuscitate injured and massively bleeding patients in the prehospital and early in-hospital phase of the resuscitation is increasing. Using group O red blood cells (RBC) and low titer group O whole blood (LTOWB) avoids an immediate hemolytic reaction from recipient's naturally occurring anti-A and - B, but choosing the RhD type for these products is more nuanced and requires the balancing of product availability and survival benefit against the risk of D-alloimmunization, especially in females of childbearing potential (FCP) due to the possible future occurrence of hemolytic disease of the fetus and newborn (HDFN). Recent models have estimated the risk of fetal/neonatal death from HDFN resulting from D-alloimmunization of an FCP during her trauma resuscitation at between 0-6.5% depending on her age at the time of the transfusion and other societal factors including trauma mortality, her age when she becomes pregnant, frequency of different RHD genotypes in the population, and the probability that the woman will have children with different fathers; this is counterbalanced by an approximately 24% risk of death from hemorrhagic shock. This review will discuss the different models of HDFN outcomes following RhD-positive transfusion as well as the results of recent surveys where the public was asked about their preferences for urgent transfusion in light of the risks of fetal/neonatal adverse events.

Whole blood transfusion among allied partnerships: unified and interoperable blood banking for optimised care

Whole blood transfusion is being increasingly used for trauma resuscitation, particularly in military settings. Low-titre group O whole blood simplifies the logistical challenges and maximises the benefits of blood transfusion when compared with component therapy in austere battlefield conditions. Screening protocols and blood testing requirements for prescreened donors in walking blood banks (WBBs), which are used for emergency transfusions, are established by both the USA and most partner nations, though they are not necessarily uniform across these combined forces. Interoperability and standardisation of blood bank resources and protocols across allied forces in multinational military operations, including uniformity in screening processes, collection methods and storage is essential to the provision of safe and effective blood product transfusions in this austere setting. Predeployment screening, multinational training exercises and universal WBB sets with instructions in multiple languages can help enhance the interoperability of combined multinational operations and create a more efficient WBB system. Standardisation of blood collection, nomenclature, equipment and screening practices will allow for the most optimal utilisation of whole blood resources across a multinational battlefield.

Management of Wrong Blood Transfusion to an RhD Negative Woman in Labor

Blood transfusion is life-saving in massive hemorrhage. Before pre-transfusion tests with ABO and RhD typing results are available, O RhD negative packed red blood cell (PRBC) units are used without cross-matching in emergency. RhD negative girls and women of child-bearing age should always receive RhD negative blood transfusions to prevent RhD-alloimmunization because anti-D-related hemolytic disease of fetus and newborn (HDFN) can result in mild to severe anemia, and in a worst-case scenario death of an RhD positive fetus and/or newborn. However, "wrong blood to wrong patient" happens unintentionally. Here we report an emergency blood transfusion with one unit of RhD positive PRBCs to an RhD negative young woman when estimated blood loss was 2500 mL during delivery and surgical removal of retained placenta. Realizing the mistake, management with high dose anti-D immunoglobulin (Ig) was initiated to remove the RhD positive red blood cells (RBCs) from the patient's circulation. Such mitigation is recommended only for girls and women of child-bearing age. Follow-up was performed by flow cytometry until RhD positive RBCs were no longer detected. Ten months after the delivery, antibody screening was negative. However, we still do not know whether we managed to prevent RhD-alloimmunization.

Modelling the outcomes of different red blood cell transfusion strategies for the treatment of traumatic haemorrhage in the prehospital setting in the United Kingdom

BACKGROUND AND OBJECTIVES

The limited supply and increasing demand of group O RhD-negative red blood cells (RBCs) have resulted in other transfusion strategies being explored by blood services that carry potential risks but may still provide an overall benefit to patients. Our aim was to analyse the potential economic benefits of prehospital transfusion (PHT) against no PHT.

MATERIALS AND METHODS

The impact of three PHT strategies (RhD-negative RBC, RhD-positive RBC and no transfusion) on quality-adjusted-life-years (QALYs) of all United Kingdom trauma patients in a given year and the subset of patients considered most at risk (RhD-negative females <50 years old), was modelled.

RESULTS

For the entire cohort and the subset of patients, transfusing RhD-negative RBCs generated the most QALYs (141,899 and 2977, respectively), followed by the RhD-positive RBCs (141,879.8 and 2958.8 respectively), and no prehospital RBCs (119,285 and 2503 respectively). The QALY difference between RhD-negative and RhD-positive policies was smaller (19.2, both cohorts) than RhD-positive and no RBCs policies in QALYs term (22,600 all cohort, 470 for a subset), indicating that harms from transfusing RhD-positive RBCs are lower than harms associated with no RBC transfusion. A survival increase from PHT of 0.02% (entire cohort) and 0.7% (subset cohort) would still make the RhD-positive strategy better in QALYs terms than no PHT.

CONCLUSION

While the use of RhD-positive RBCs carries risks, the benefits measured in QALYs are higher than if no PHT are administered, even for women of childbearing potential. Group O RhD-positive RBCs could be considered when there is a national shortage of RhD-negative RBCs.

Attitudes of American adult women toward accepting RhD-mismatched transfusions in bleeding emergencies

BACKGROUND

There is an increasing literature demonstrating the benefits of prehospital and early in-hospital transfusions. RhD-positive products might only be available during these phases, which could pose consequences for future pregnancies if D-alloimmunization occurs. This survey measured the willingness of females to accept urgent but incompatible transfusions in light of the potential for future pregnancy complications.

METHODS

A survey was designed to assess the willingness of females ≥18 years of age to accept urgent incompatible transfusions when different absolute risk reductions in maternal mortality were presented along with a static rate of 0.3%-4.0% risk of harm to future pregnancies. The survey was sent electronically to women who are part of the Washington University Research Enhancement Core database.

RESULTS

A total of 4896 delivered survey email invitations were distributed and 325 (6.6%) responses were received; 16 responses were excluded leaving 309 responses for analysis. Most of the responding women were White, college-educated, and lived in Missouri. At least 90% of the respondents would accept an urgent incompatible transfusion when the absolute risk reduction in maternal mortality was ≥4%. Women without a college degree, who lived in Illinois, who were not able to have children appeared to be less willing than their counterparts to receive an incompatible transfusion when the absolute risk reduction in maternal mortality was low.

CONCLUSION

This survey demonstrated that adult women are highly likely to be open to accept urgent incompatible blood transfusions during a bleeding emergency when the absolute risk reduction in maternal mortality was ≥4%.

Rate of D-alloimmunization in trauma does not depend on the number of RhD-positive units transfused: The BEST collaborative study

BACKGROUND

Evidence indicates the life-saving benefits of early blood product transfusion in severe trauma resuscitation. Many of these products will be RhD-positive, so understanding the D-alloimmunization rate is important.

METHODS

This was a multicenter, retrospective study whereby injured RhD-negative patients between 18-50 years of age who received at least one unit of RhD-positive red blood cells (RBC) or low titer group O whole blood (LTOWB) during their resuscitation between 1 January, 2010 through 31 December, 2019 were identified. If an antibody detection test was performed ≥14 days after the index RhD-positive transfusion then basic demographic information was collected, including whether the patient became D-alloimmunized. The overall D-alloimmunization rate, and the rate stratified by the number of units transfused, were calculated.

RESULTS

Data were collected from nine institutions. Five institutions reported fewer than 10 eligible patients each and were excluded. From the remaining four institutions, all from the USA, there were 235 eligible patients; 77 (random effects estimate: 32.7%; 95% CI: 19.1-50.1%) became D-alloimmunized. Three of the institutions reported D-alloimmunization rates ≥38.6%, while the remaining institution's rate was 12.2%. In both random and fixed-effects models, the rate of D-alloimmunization was not significantly different between those who received one RhD-positive unit and those who received multiple RhD-positive units.

CONCLUSION

In this large, multicenter study of injured patients, the overall rate of D-alloimmunization fell within the range previously reported. The rate of D-alloimmunization did not increase as the number of transfused RhD-positive units increased. These data can help to inform RhD type selection decisions.

The regional whole blood program in San Antonio, TX: A 3-year update on prehospital and in-hospital transfusion practices for traumatic and non-traumatic hemorrhage

Low titer type O Rh-D + whole blood (LTO + WB) has become a first-line resuscitation medium for hemorrhagic shock in many centers around the World. Showing early effectiveness on the battlefield, LTO + WB is used in both the pre-hospital and in-hospital settings for traumatic and non-traumatic hemorrhage resuscitation. Starting in 2018, the San Antonio Whole Blood Collaborative has worked to provide LTO + WB across Southwest Texas, initially in the form of remote damage control resuscitation followed by in-hospital trauma resuscitation. This program has since expanded to include pediatric trauma resuscitation, obstetric hemorrhage, females of childbearing potential, and non-traumatic hemorrhage. The objective of this manuscript is to provide a three-year update on the successes and expansion of this system and outline resuscitation challenges in special populations.

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.

THOR-AABB Working Party Recommendations for a Prehospital Blood Product Transfusion Program

The evidence for the lifesaving benefits of prehospital transfusions is increasing. As such, emergency medical services (EMS) might increasingly become interested in providing this important intervention. While a few EMS and air medical agencies have been providing exclusively red blood cell (RBC) transfusions to their patients for many years, transfusing plasma in addition to the RBCs, or simply using low titer group O whole blood (LTOWB) in place of two separate components, will be a novel experience for many services. The recommendations presented in this document were created by the Trauma, Hemostasis and Oxygenation Research (THOR)-AABB (formerly known as the American Association of Blood Banks) Working Party, and they are intended to provide a framework for implementing prehospital blood transfusion programs in line with the best available evidence. These recommendations cover all aspects of such a program including storing, transporting, and transfusing blood products in the prehospital phase of hemorrhagic resuscitation.

Survey of the RhD selection and issuing practices for uncrossmatched blood products at pediatric trauma hospitals in the United States: The BEST collaborative study

BACKGROUND

As evidence demonstrating the importance of early transfusions in trauma resuscitation accumulates, when RhD-negative products might not be available, it is important to understand the nature of the RhD-type of products provided to bleeding pediatric patients of potentially unknown RhD-type.

METHODS

A survey link was electronically sent to the transfusion service medical director and/or laboratory manager at American pediatric Level I and Level II hospitals inquiring about their practices for selecting RhD-type of uncrossmatched red blood cells (RBC) or low titer group O whole blood (LTOWB) for boys and girls.

RESULTS

There were 55/117 (47.0%) analyzable responses; 43/55 (78.2%) from Level I and 12/55 (21.8%) from Level II hospitals. For in hospital transfusions, 51/55 (92.7%) of centers use only RhD-negative blood products to resuscitate girls ≤18 years old while 30/55 (54.5%) of centers do the same for boys ≤18 years old. Most centers 41/55(74.5%) store RBCs and/or LTOWB in in-hospital remote refrigerators; 27 store only RhD-negative RBCs and 2 store only RhD-negative LTOWB units in these refrigerators. A total of 24/55 (43.6%) centers have RBCs and/or LTOWB available on road ambulances or helicopters for prehospital transfusion; 12 transport only RhD-negative RBCs and two transport only RhD-negative LTOWB. Most centers, 35/55 (63.6%), address the prophylaxis of an RhD-negative female recipient of RhD-positive transfusion on a case-by-case basis.

CONCLUSION

While there is some variability, most of the responding pediatric trauma centers routinely utilized RhD-negative RBCs for emergency transfusion for patients ≤18 years old of unknown RhD-type.

Rate of RhD-alloimmunization after the transfusion of multiple RhD-positive primary red blood cell-containing products

INTRODUCTION

Early transfusion reduces mortality in bleeding patients. In this setting, RhD-positive blood products might be transfused. This study determined the association between the RhD-alloimmunization rate and the number of RhD-positive products transfused.

METHODS

RhD-negative patients between 13 and 50 years who were transfused with ≥1 RhD-positive red blood cell (RBC) or whole blood units between January 1, 2000 and December 31, 2019 in a healthcare network were identified. Study patients had to have had at least one antibody detection test performed ≥14 days after the index RhD-positive transfusion and not receive RhIg. Patients were stratified into groups that received 1, 2, 3-5, 6-10, 11-20, and >20 RhD-positive transfusions and the RhD-alloimmunization rate was determined for each group.

RESULTS

There were 335 patients included; 52/335 (15.5%) were females. Overall, there were 117/335 (34.9%, CI: 29.8%-40.3%) recipients who became RhD-alloimmunized. There was no significant dosage effect in the RhD-alloimmunization rates as the exposure to RhD-positive units increased from one RhD-positive unit to more than 20 RhD-positive units (p = .270 for non-parametric trend test). In an exploratory analysis, patients who received 100% of their RhD-positive transfusions within 72 h of the index transfusion had a significantly higher rate of RhD-alloimmunization compared to those who were transfused over a longer period of time (42.3% vs. 21.4%, respectively; p = .001).

CONCLUSION

These results suggest that there may not be an increased RhD-alloimmunization risk with transfusing multiple RhD-positive units after one RhD-positive unit has been transfused. These findings need confirmation in larger studies.

Survey to inform trial of low-titer group O whole-blood compared to conventional blood components for children with severe traumatic bleeding

BACKGROUND

Low-titer group O whole-blood (LTOWB) is being used for children with life-threatening traumatic bleeding. A survey was conducted to determine current LTOWB utilization and interest in participation in a randomized control trial (RCT) of LTOWB versus standard blood component transfusion in this population.

STUDY DESIGN AND METHODS

Transfusion medicine (TM) directors and pediatric trauma directors at 36 US children's hospitals were surveyed by e-mail in June 2020. Hospitals were selected by participation in the Massive Transfusion Epidemiology and Outcomes in Children Study or being among the largest 30 children's hospitals by bed capacity per the Becker Hospital Review.

RESULTS

The response rate was 83.3% (30/36) from TM directors and 88.9% (32/36) from trauma directors. The median of massive transfusion protocol activations for traumatic bleeding was reported as 12 (IQR 5.8-20) per year by TM directors. LTOWB was used by 18.8% (6/32) of trauma directors. Survey responses indicate that 86.7% (26/30) of TM directors and 90.6% (29/32) of trauma directors either moderately or strongly agree that a LTOWB RCT is important to perform. About 83.3% (25/30) of TM directors and 93.8% (30/32) of trauma directors were willing to participate in the proposed trial. About 80% (24/30) of TM directors and 71.9% (23/32) of trauma directors would transfuse RhD+ LTOWB to male children, but fewer would transfuse Rh + LTOWB to females [20% (6/30) TM directors and 37.5% (12/32) of trauma directors].

CONCLUSIONS

A majority of respondents supported an RCT comparing LTOWB to component therapy in children with severe traumatic bleeding.

Survey of group A plasma and low-titer group O whole blood use in trauma resuscitation at adult civilian level 1 trauma centers in the US

BACKGROUND

Recently revisited products like low-titer group O whole blood (LTOWB) and novel applications of group A as a universal donor of plasma are being used for trauma resuscitation. A survey of American Level 1 trauma centers was performed to elucidate the extent to which these products are currently employed.

METHODS

A survey was written that probed into the current use of blood products in trauma resuscitation with specific emphasis on LTOWB and group A plasma. A list of adult civilian Level 1 trauma centers in the continental USA was obtained from two public surgery and trauma focused websites. An email was then sent to each center's transfusion service medical director or laboratory manager providing them with a link to the online survey.

RESULTS

Responses were received from 103/187 (55%) adult civilian Level 1 trauma centers. For the resuscitation of trauma patients, group A plasma was used at 94/103 (91%) centers, while LTOWB was used at 43/103 (42%) centers. There were 39/103 (38%) centers that used both products. At 62/94 (66%) of the centers that used group A plasma, there was no limit on the number of units that could be administered, while an unlimited number of LTOWB units could be used at 5/43 (12%) of the centers that used LTOWB. RhD-positive LTOWB could be transfused to RhD-negative or RhD-type unknown females of childbearing potential at 22/43 (51%) of centers.

CONCLUSION

The use of group A plasma and LTOWB in trauma is increasing at American Level 1 trauma centers.