Finding the bleeding edge: 24-hour mortality by unit of blood product transfused in combat casualties from 2002-2020

Markers of Futile Resuscitation in Traumatic Hemorrhage: A Review of the Evidence and a Proposal for Futility Time-Outs during Massive Transfusion

The reduction in the blood supply following the 2019 coronavirus pandemic has been exacerbated by the increased use of balanced resuscitation with blood components including whole blood in urban trauma centers. This reduction of the blood supply has diminished the ability of blood banks to maintain a constant supply to meet the demands associated with periodic surges of urban trauma resuscitation. This scarcity has highlighted the need for increased vigilance through blood product stewardship, particularly among severely bleeding trauma patients (SBTPs). This stewardship can be enhanced by the identification of reliable clinical and laboratory parameters which accurately indicate when massive transfusion is futile. Consequently, there has been a recent attempt to develop scoring systems in the prehospital and emergency department settings which include clinical, laboratory, and physiologic parameters and blood products per hour transfused as predictors of futile resuscitation. Defining futility in SBTPs, however, remains unclear, and there is only nascent literature which defines those criteria which reliably predict futility in SBTPs. The purpose of this review is to provide a focused examination of the literature in order to define reliable parameters of futility in SBTPs. The knowledge of these reliable parameters of futility may help define a foundation for drawing conclusions which will provide a clear roadmap for traumatologists when confronted with SBTPs who are candidates for the declaration of futility. Therefore, we systematically reviewed the literature regarding the definition of futile resuscitation for patients with trauma-induced hemorrhagic shock, and we propose a concise roadmap for clinicians to help them use well-defined clinical, laboratory, and viscoelastic parameters which can define futility.

The thin red line: Blood planning factors and the enduring need for a robust military blood system to support combat operations

ABSTRACT

Battlefield lessons learned are forgotten; the current name for this is the Walker Dip. Blood transfusion and the need for a Department of Defense Blood Program are lessons that have cycled through being learned during wartime, forgotten, and then relearned during the next war. The military will always need a blood program to support combat and contingency operations. Also, blood supply to the battlefield has planning factors that have been consistent over a century. In 2024, it is imperative that we codify these lessons learned. The linchpins of modern combat casualty care are optimal prehospital care, early whole blood transfusion, and forward surgical care. This current opinion comprised of authors from all three military Services, the Joint Trauma System, the Armed Services Blood Program, blood SMEs and the CCC Research Program discuss two vital necessities for a successful military trauma system: (1) the need for an Armed Services Blood Program and (2) Planning factors for current and future deployed military ere is no effective care for wounded soldiers, and by extension there is no effective military medicine.

A Scoping Review of Military Combat Casualty Data on Submassive, Massive, and Supermassive Transfusions

INTRODUCTION

Blood transfusions are common during combat casualty care, aiming to address the loss of blood volume that often accompanies severe battlefield injuries. This scoping review delves into the existing military combat casualty data to analyze the efficacy, challenges, and advances in the use of massive and super-massive transfusions in the management of critically injured warfighters.

MATERIALS AND METHODS

We performed a scoping review of combat-related literature published between 2006 and 2023 pertaining to massive transfusions used during combat deployments. We utilized PubMed to identify relevant studies and utilized the PRISMA-ScR Checklist to conduct the review.

RESULTS

We identified 53 studies that met the inclusion criteria with the majority being retrospective studies from registries used by the United States, British, French, and Dutch Militaries. Most of the studies focused on transfusion ratios, the movement of blood transfusions to more forward locations, implementation of massive transfusions with different fibrinogen-to-red blood cell ratios, the addition of recombinant factor VII, and the use of predictive models for transfusion. Lastly, we identified reports of improved survival for casualties with the rapid implementation of various blood products (warm fresh whole blood, cold-stored low titer group O blood, freeze-dried plasma, and component therapy) and literature relating to pediatric casualties and submassive transfusions. Notable findings include the establishment of hemodynamic and cell blood count parameters as predictors of the requirement for massive transfusions and the association of higher fibrinogen-to-red blood cell ratios with decreased mortality.

CONCLUSIONS

We identified 53 studies focused on blood transfusions from the Global War on Terrorism conflicts. The majority were related to transfusion ratios and the movement of blood transfusions to more forward locations. We highlight key lessons learned on the battlefield that have been translated into scientific developments and changes in civilian trauma methods.

Expired blood transfusion and mortality outcomes in combat trauma patients

BACKGROUND

Expired blood can be transfused if clinically indicated but outcome data do not exist. We hypothesized that modestly outdated blood can effectively support a hemorrhaging patient until surgical control is achieved. This study assessed whether expired blood was associated with mortality in combat trauma patients.

STUDY DESIGN AND METHODS

A retrospective analysis of Armed Services Blood Program and Department of Defense Trauma Registry databases evaluated combat casualty records (2001-2023). The intervention of interest was transfusion of at least one unit of whole blood (WB), red blood cells (RBC), or platelets within one week past expiration. The outcome of interest was mortality at discharge. A control cohort that only received in-date blood was matched to the treatment cohort for logistic regression analysis.

RESULTS

One hundred patients received expired RBCs (86), WB (11), and platelets (3). Mortality at discharge was 11.6% for expired RBC recipients and 13.4% for the control cohort (p = .97). After adjustment for injury severity, expired RBCs were not associated with mortality (OR = 0.40 [95% CI, 0.14-1.16]; p = .09). Of 10 patients who received the most expired RBCs by volume or storage duration, two were deceased at discharge. All 14 expired WB and platelet recipients were alive at discharge, but sample sizes were underpowered for regression analysis.

DISCUSSION

Transfusion of modestly outdated RBCs was not associated with mortality in combat trauma patients. Expired WB and platelet recipients did well, but sample sizes were too small to draw significant conclusions. Expired blood should be further investigated for possible use in extenuating circumstances.

Association between transfusion volume and survival outcome following trauma: Insight into the limit of transfusion from an analysis of nationwide trauma registry in Japan

BACKGROUND

Whether and how the transfusion volume should be limited in resuscitation after trauma remains unclear. We investigated the association between transfusion volume and survival outcome following trauma.

METHODS

Using the Japan Trauma Data Bank (2019-2021), we identified patients 18 years or older who received balanced blood transfusion within the first 24 hours of injury. We evaluated the association between the total number of red blood cell (RBC) units transfused and survival at discharge using logistic regression analysis and generalized additive model. Subgroup analyses based on patient characteristics were performed.

RESULTS

Overall, 5,123 patients from 165 hospitals were eligible for analysis. The transfusion volume was significantly associated with survival rate. Compared with that of patients receiving 4 to 9 RBC units, the within-hospital odds ratios (95% confidence interval) for survival at discharge were 0.62 (0.55-0.75), 0.32 (0.25-0.40), and 0.15 (0.12-0.20) for those receiving 10 to 19, 20 to 29, and ≥30 U, respectively. The probability of survival decreased consistently without any discernible threshold; however, the survival rates remained >40% and >20% even in patients receiving 50 and 80 RBC units, respectively. Significant interactions were observed between the number of RBC units transfused and each subgroup for survival at discharge.

CONCLUSION

The probability of survival consistently diminished as the transfusion volume increased. The absence of a threshold and lack of exceedingly low probability of survival support massive transfusion when clinicians perceive ongoing transfusion as beneficial. The unique context of each clinical situation must be considered in decision making.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level III.

Blood consumption in the Role 2 setting: A Department of Defense Trauma Registry analysis

BACKGROUND

The Role 2 setting represents the most far-forward military treatment facility with limited surgical and holding capabilities. There are limited data to guide recommendations on blood product utilization at the Role 2. We describe the consumption of blood products in this setting.

STUDY DESIGN AND METHODS

We analyzed data from 2007 to 2023 from the Department of Defense Trauma Registry (DODTR) that received care at a Role 2. We used descriptive and inferential statistics to characterize the volumes of blood products consumed in this setting. We also performed a secondary analysis of US military, Coalition, and US contractor personnel.

RESULTS

Within our initial cohort analysis of 15,581 encounters, 17% (2636) received at least one unit of PRBCs or whole blood, of which 11% received a submassive transfusion, 4% received a massive transfusion, and 1% received a supermassive transfusion. There were 6402 encounters that met inclusion for our secondary analysis. With this group, 5% received a submassive transfusion, 2% received a massive transfusion, and 1% received a supermassive transfusion.

CONCLUSIONS

We described volumes of blood products consumed at the Role 2 during recent conflicts. The maximum number of units consumed among survivors exceeds currently recommended available blood supply. Our findings suggest that rapid resupply and cold-stored chain demands may be higher than anticipated in future conflicts.

TiME OUT: Time-specific machine-learning evaluation to optimize ultramassive transfusion

BACKGROUND

Ultramassive transfusion (UMT) is a resource-demanding intervention for trauma patients in hemorrhagic shock, and associated mortality rates remains high. Current research has been unable to identify a transfusion ceiling or point where UMT transitions from lifesaving to futility. Furthermore, little consideration has been given to how time-specific patient data points impact decisions with ongoing high-volume resuscitation. Therefore, this study sought to use time-specific machine learning modeling to predict mortality and identify parameters associated with survivability in trauma patients undergoing UMT.

METHODS

A retrospective review was conducted at a Level I trauma (2018-2021) and included trauma patients meeting criteria for UMT, defined as ≥20 red blood cell products within 24 hours of admission. Cross-sectional data were obtained from the blood bank and trauma registries, and time-specific data were obtained from the electronic medical record. Time-specific decision-tree models predicating mortality were generated and evaluated using area under the curve.

RESULTS

In the 180 patients included, mortality rate was 40.5% at 48 hours and 52.2% overall. The deceased received significantly more blood products with a median of 71.5 total units compared with 55.5 in the survivors ( p < 0.001) and significantly greater rates of packed red blood cells and fresh frozen plasma at each time interval. Time-specific decision-tree models predicted mortality with an accuracy as high as 81%. In the early time intervals, hemodynamic stability, undergoing an emergency department thoracotomy, and injury severity were most predictive of survival, while, in the later intervals, markers of adequate resuscitation such as arterial pH and lactate level became more prominent.

CONCLUSION

This study supports that the decision of "when to stop" in UMT resuscitation is not based exclusively on the number of units transfused but rather the complex integration of patient and time-specific data. Machine learning is an effective tool to investigate this concept, and further research is needed to refine and validate these time-specific decision-tree models.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.