Whole blood at the tip of the spear: A retrospective cohort analysis of warm fresh whole blood resuscitation versus component therapy in severely injured combat casualties

FINDING THE SWEET SPOT: THE ASSOCIATION BETWEEN WHOLE BLOOD TO RED BLOOD CELLS RATIO AND OUTCOMES OF HEMORRHAGING CIVILIAN TRAUMA PATIENTS

ABSTRACT

Purpose: To evaluate the dose-dependent effect of whole blood (WB) on the outcomes of civilian trauma patients with hemorrhagic shock. Methods: We performed a 2-year (2020-2021) retrospective analysis of the ACS-TQIP dataset. Adult (≥18) trauma patients with a shock index (SI) >1 who received at least 5 units of PRBC and one unit of WB within the first 4 h of admission were included. Primary outcomes were 6-h, 24-h, and in-hospital mortality. Secondary outcomes were major complications and hospital and intensive care unit length of stay. Results: A total of 830 trauma patients with a mean (SD) age of 38 (16) were identified. The median [IQR] 4-h WB and PRBC requirements were 2 [2-4] U and 10 [7-15] U, respectively, with a median WB:RBC ratio of 0.2 [0.1-0.3]. Every 0.1 increase in WB:RBC ratio was associated with decreased odds of 24-h mortality (aOR: 0.916, P = 0.035) and in-hospital mortality (aOR: 0.878, P < 0.001). Youden's index identified 0.25 (1 U of WB for every 4 U of PRBC) as the optimal WB:PRBC ratio to reduce 24-h mortality. High ratio (≥0.25) group had lower adjusted odds of 24-h mortality (aOR: 0.678, P = 0.021) and in-hospital mortality (aOR: 0.618, P < 0.001) compared to the low ratio group. Conclusions: A higher WB:PRBC ratio was associated with improved early and late mortality in trauma patients with hemorrhagic shock. Given the availability of WB in trauma centers across the United States, at least one unit of WB for every 4 units of packed red blood cells may be administered to improve the survival of hemorrhaging civilian trauma patients.

Type-specific whole blood still has a role in the era of low-titer O universal donor transfusion for severe trauma hemorrhage

ABSTRACT

Whole blood can be ABO-type specific (type-specific whole blood (TSWB)) or low-titer O universal donor (low-titer O whole blood (LTOWB)). Having previously used LTOWB, the US Armed Forces Blood Program began using TSWB in 1965 as a method of increasing the donor pool. In contrast to military practice, the Association for the Advancement of Blood and Biotherapies formerly the American association of blood banks (AABB), from its first guidelines in 1958 until 2018, permitted only TSWB. Attempting to reduce time to transfusion, the US military reintroduced LTOWB in the deployed environment in 2015; this practice was endorsed by the AABB in 2018 and is progressively being implemented by military and civilian providers worldwide. Low-titer O whole blood is the only practical solution prehospital. However, there are several reasons to retain the option of TSWB in hospitals with a laboratory. These include (1) as-yet ill-defined risks of immunological complications from ABO-incompatible plasma (even when this has low titers of anti-A and -B), (2) risks of high volumes of LTOWB including published historical advice (based on clinical experience) not to transfuse type-specific blood for 2 to 3 weeks following a substantial LTOWB transfusion, (3) uncertainty as to the optimal definition of "low titer," and (4) expanding the potential donor pool by allowing type-specific transfusion. Several large randomized controlled trials currently underway are comparing LTOWB with component therapy, but none address the question of LTOWB versus TSWB. There are sufficient data to suggest that the additional risks of transfusing LTOWB to non-group O recipients should be avoided by using TSWB as soon as possible. Combined with the advantage of maintaining an adequate supply of blood products in times of high demand, this suggests that retaining TSWB within the civilian and military blood supply system is desirable. TSWB should be preferred when patient blood group is confirmed in facilities with a hematology laboratory, with LTOWB reserved for patients whose blood group is unknown.

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 trauma expert consensus: Capabilities are required early to improve survivability from traumatic injury

BACKGROUND

Mortality reviews examine US military fatalities resulting from traumatic injuries during combat operations. These reviews are essential to the evolution of the military trauma system to improve individual, unit, and system-level trauma care delivery and inform trauma system protocols and guidelines. This study identifies specific prehospital and hospital interventions with the potential to provide survival benefits.

METHODS

US Special Operations Command fatalities with battle injuries deemed potentially survivable (2001-2021) were extracted from previous mortality reviews. A military trauma review panel consisting of trauma surgeons, forensic pathologists, and prehospital and emergency medicine specialists conducted a methodical review to identify prehospital, hospital, and resuscitation interventions (e.g., laparotomy, blood transfusion) with the potential to have provided a survival benefit.

RESULTS

Of 388 US Special Operations Command battle-injured fatalities, 100 were deemed potentially survivable. Of these (median age, 29 years; all male), 76.0% were injured in Afghanistan, and 75% died prehospital. Gunshot wounds were in 62.0%, followed by blast injury (37%), and blunt force injury (1.0%). Most had a Maximum Abbreviated Injury Scale severity classified as 4 (severe) (55.0%) and 5 (critical) (41.0%). The panel recommended 433 interventions (prehospital, 188; hospital, 315). The most recommended prehospital intervention was blood transfusion (95%), followed by finger/tube thoracostomy (47%). The most common hospital recommendations were thoracotomy and definitive vascular repair. Whole blood transfusion was assessed for each fatality: 74% would have required ≥10 U of blood, 20% would have required 5 to 10 U, 1% would have required 1 to 4 U, and 5% would not have required blood products to impact survival. Five may have benefited from a prehospital laparotomy.

CONCLUSION

This study systematically identified capabilities needed to provide a survival benefit and examined interventions needed to inform trauma system efforts along the continuum of care. The determination was that blood transfusion and massive transfusion shortly after traumatic injury would impact survival the most.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level V.

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.

Association between whole blood ratio and risk of mortality in massively transfused trauma patients: retrospective cohort study

BACKGROUND

Although whole blood (WB) transfusion was reported to improve survival in trauma patients with hemorrhagic shock, little is known whether a higher proportion of WB is associated with an improved survival. This study aimed to evaluate the association between whole blood ratio (WBR) and the risk of mortality in trauma patients requiring massive blood transfusion.

METHODS

We performed a retrospective cohort study from the ACS-TQIP between 2020 and 2021. Patients were aged ≥ 18 years and received WB within 4 h of hospital arrival as a part of massive blood transfusion. Study patients were categorized into four groups based on the quartiles of WBR. Primary outcome was 24-h mortality and secondary outcome was 30-day mortality. Multivariable logistic regression analysis, fitted with generalized estimating equations, was performed to adjust for confounding factors and accounted for within-hospital clustering.

RESULTS

A total of 4087 patients were eligible for analysis. The median age was 37 years (interquartile range [IQR]: 27-53 years), and 85.0% of patients were male. The median number of WB transfusions was 2.3 units (IQR 2.0-4.0 units), and the total transfusion volume was 4940 ml (IQR 3350-8504). When compared to the lowest WBR quartile, the highest WBR quartile had lower adjusted 24-h mortality (adjusted odds ratio [AOR]: 0.61, 95% confidence interval [CI]: 0.46-0.81) and 30-day mortality (AOR 0.58; 95% CI 0.45-0.75).

CONCLUSION

The probability of mortality consistently decreased with higher WBR in trauma patients requiring massive blood transfusion.

What's new in whole blood resuscitation? In the trauma bay and beyond

PURPOSE OF REVIEW

Transfusion therapy commonly supports patient care during life-threatening injury and critical illness. Herein we examine the recent resurgence of whole blood (WB) resuscitation for patients in hemorrhagic shock following trauma and other causes of severe bleeding.

RECENT FINDINGS

A growing body of literature supports the use of various forms of WB for hemostatic resuscitation in military and civilian trauma practice. Different types of WB include warm fresh whole blood (FWB) principally used in the military and low titer O cold stored whole blood (LTOWB) used in a variety of military and civilian settings. Incorporating WB initial resuscitation alongside subsequent component therapy reduces aggregate blood product utilization and improves early mortality without adversely impacting intensive care unit length of stay or infection rate. Applications outside the trauma bay include prehospital WB and use in patients with nontraumatic hemorrhagic shock.

SUMMARY

Whole blood may be transfused as FWB or LTOWB to support a hemostatic approach to hemorrhagic shock management. Although the bulk of WB resuscitation literature has appropriately focused on hemorrhagic shock following injury, extension to other etiologies of severe hemorrhage will benefit from focused inquiry to address cost, efficacy, approach, and patient-centered outcomes.

Frequency of deployed emergency donor panel use prior to implementation of the low titre group O whole blood program

INTRODUCTION

The US military has frequently used a 'walking blood bank', formally known as an 'emergency donor panel' (EDP) to obtain warm fresh whole blood (WFWB) which is then immediately transfused into the casualty. We describe the frequency of EDP activation by the US military.

METHODS

We analysed data from 2007 to 2015 within the Department of Defense Trauma Registry for US, Coalition and US contractor casualties that received at least 1 unit of blood product within the first 24 hours and described the frequency of WFWB use.

RESULTS

There were 3474 casualties that met inclusion, of which, 290 casualties (8%) required activation of the EDP. The highest proportion of EDP events was in 2014, whereas the highest number of EDP events was in 2011. Median injury severity scores were higher in the recipients, compared with non-EDP recipients (29 vs 20), as were proportions with serious injuries to the abdomen (43% vs 19%) and extremities (77% vs 65%). The median number of units of all blood products, except for packed red blood cells, was higher for WFWB recipients. Of the WFWB recipients, the median was 5 units (IQR 2-10) with a maximum documented 144 units. There were four documented cases of EDP recipients receiving >100 units of WFWB with only one surviving to hospital discharge. During the study period, there were a total of 3102 (3%) units of WFWB transfused among a total of 104 288 total units.

CONCLUSIONS

We found nearly 1 in 11 casualties who received blood required activation of the EDP. Blood from the EDP accounted for 3% of all units transfused. These findings will enable future mission planning and medical training, especially for units with smaller, limited blood supplies. The lessons learned here can also enable mass casualty planning in civilian settings.

The first two years of the use of low titer group O whole blood during French Military overseas operations: A retrospective study

BACKGROUND

On the battlefield, hemorrhage is the main cause of potentially preventable death. To reduce mortality due to hemorrhagic injuries, the French Military Medical Service (FMMS) has deployed low titer group O whole blood (LTOWB) since June 2021 during operation BARKHANE in the Sahel-Saharan strip. Questions persist regarding the circumstances under which the FMMS employs LTOWB during overseas operations.

STUDY DESIGN

We performed a retrospective analysis of all LTOWB transfused by the FMMS during overseas operations in the Sahel-Saharan strip between June 1, 2021, and June 1, 2023. Information was collected from battlefield forward transfusion sheets.

RESULTS

Over the 2-year study period, 40 units of LTOWB were transfused into 25 patients. Of the 25 patients, 18 were combat casualties and seven were transfused for non-trauma surgery. Of the 40 units of LTOWB transfused, 22 were provided during Role 2 care, 11 during tactical medical evacuation (MEDEVAC), and seven in light and mobile surgical units. Among combat casualties, LTOWB was the first blood product transfused in 13 patients. In combat casualties, 6 h post-trauma, the median ratio of plasma: red blood cells (RBCs) was 1.5, and the median equivalent platelet concentrate (PC) transfused was 0.17. No immediate adverse events related to LTOWB transfusion were reported.

CONCLUSION

LTOWB is transfused by the FMMS during overseas operations from the tactical MEDEVAC until Role 2 care. Deployment of LTOWB by the FMMS enables an early high-ratio plasma/RBC transfusion and an early platelet transfusion for combat casualties.

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.

Preferential whole blood transfusion during the early resuscitation period is associated with decreased mortality and transfusion requirements in traumatically injured patients

Introduction

Whole blood (WB) transfusion represents a promising resuscitation strategy for trauma patients. However, a paucity of data surrounding the optimal incorporation of WB into resuscitation strategies persists. We hypothesized that traumatically injured patients who received a greater proportion of WB compared with blood product components during their resuscitative efforts would have improved early mortality outcomes and decreased transfusion requirements compared with those who received a greater proportion of blood product components.

Methods

Retrospective review from our Level 1 trauma center of trauma patients during their initial resuscitation (2019-2022) was performed. WB to packed red blood cell ratios (WB:RBC) were assigned to patients based on their respective blood product resuscitation at 1, 2, 3, and 24 hours from presentation. Multivariable regression models were constructed to assess the relationship of WB:RBC to 4 and 24-hour mortality, and 24-hour transfusion requirements.

Results

390 patients were evaluated (79% male, median age of 33 years old, 48% penetrating injury rate, and a median Injury Severity Score of 27). Overall mortality at 4 hours was 9%, while 24-hour mortality was 12%. A significantly decreased 4-hour mortality was demonstrated in patients who displayed a WB:RBC≥1 at 1 hour (5.9% vs. 12.3%; OR 0.17, p=0.015), 2 hours (5.5% vs. 13%; OR 0.16, p=0.019), and 3 hours (5.5% vs. 13%, OR 0.18, p<0.01), while a decreased 24-hour mortality was displayed in those with a WB:RBC≥1 at 24 hours (7.9% vs. 14.6%, OR 0.21, p=0.01). Overall 24-hour transfusion requirements were significantly decreased within the WB:RBC≥1 cohort (12.1 units vs. 24.4 units, p<0.01).

Conclusion

Preferential WB transfusion compared with a balanced transfusion strategy during the early resuscitative period was associated with a lower 4 and 24-hour mortality, as well as decreased 24-hour transfusion requirements, in trauma patients. Future prospective studies are warranted to determine the optimal use of WB in trauma.

Level of evidence

Level III/therapeutic.

Empiric Cryoprecipitate Transfusion in Patients with Severe Hemorrhage: Results from the US Experience in the International CRYOSTAT-2 Trial

BACKGROUND

Hypofibrinogenemia has been shown to predict massive transfusion and is associated with higher mortality in severely injured patients. However, the role of empiric fibrinogen replacement in bleeding trauma patients remains controversial. We sought to determine the effect of empiric cryoprecipitate as an adjunct to a balanced transfusion strategy (1:1:1).

STUDY DESIGN

This study is a subanalysis of patients treated at the single US trauma center in a multicenter randomized controlled trial. Trauma patients (more than 15 years) were eligible if they had evidence of active hemorrhage requiring emergent surgery or interventional radiology, massive transfusion protocol (MTP) activation, and received at least 1 unit of blood. Transfer patients, those with injuries incompatible with life, or those injured more than 3 hours earlier were excluded. Patients were randomized to standard MTP (STANDARD) or MTP plus 3 pools of cryoprecipitate (CRYO). Primary outcomes included all-cause mortality at 28 days. Secondary outcomes were transfusion requirements, intraoperative and postoperative coagulation laboratory values, and quality-of-life measures (Glasgow outcome score-extended).

RESULTS

Forty-nine patients (23 in the CRYO group and 26 in the STANDARD group) were enrolled between May 2021 and October 2021. Time to randomization was similar between groups (14 vs 24 minutes, p = 0.676). Median time to cryoprecipitate was 41 minutes (interquartile range 37 to 48). There were no differences in demographics, arrival physiology, laboratory values, or injury severity. Intraoperative and ICU thrombelastography values, including functional fibrinogen, were similar between groups. There was no benefit to CRYO with respect to post-emergency department transfusions (intraoperative and ICU through 24 hours), complications, Glasgow outcome score, or mortality.

CONCLUSIONS

In this study of severely injured, bleeding trauma patients, empiric cryoprecipitate did not improve survival or reduce transfusion requirements. Cryoprecipitate should continue as an "on-demand" addition to a balanced transfusion strategy, guided by laboratory values and should not be given empirically.

Use of Low-Titer O-Positive Whole Blood in Female Trauma Patients: A Literature Review, Qualitative Multidisciplinary Analysis of Risk/Benefit, and Guidelines for Its Use as a Universal Product in Hemorrhagic Shock

BACKGROUND

Whole blood transfusion is associated with benefits including improved survival, coagulopathy, and decreased transfusion requirements. The majority of whole blood transfusion is in the form of low-titer O-positive whole blood (LTOWB). Practice at many trauma centers withholds the use of LTOWB in women of childbearing potential due to concerns of alloimmunization. The purpose of this article is to review the evidence for LTOWB transfusion in female trauma patients and generate guidelines for its application.

STUDY DESIGN

Literature and evidence for LTOWB transfusion in hemorrhagic shock are reviewed. The rates of alloimmunization and subsequent obstetrical outcomes are compared to the reported outcomes of LTOWB vs other resuscitation media. Literature regarding patient experiences and preferences in regards to the risk of alloimmunization is compared to current trauma practices.

RESULTS

LTOWB has shown improved outcomes in both military and civilian settings. The overall risk of alloimmunization for Rhesus factor (Rh) - female patients in hemorrhagic shock exposed to Rh + blood is low (3% to 20%). Fetal outcomes in Rh-sensitized patients are excellent compared to historical standards, and treatment options continue to expand. The majority of female patients surveyed on the risk of alloimmunization favor receiving Rh + blood products to improve trauma outcomes. Obstetrical transfusion practices have incorporated LTOWB with excellent results.

CONCLUSIONS

The use of whole blood resuscitation in trauma is associated with benefits in the resuscitation of severely injured patients. The rate at which severely injured, Rh-negative patients develop anti-D antibodies is low. Treatments for alloimmunized pregnancies have advanced, with excellent results. Fears of alloimmunization in female patients are likely overstated and may not warrant the withholding of whole blood resuscitation. The benefits of whole blood resuscitation likely outweigh the risks of alloimmunization.

Comparative Analysis of Whole Blood Infusion Effects: Assessing LifeFlow Versus Pressure Bag in a Sus scrofa Model

BACKGROUND

To improve survival for hemorrhagic shock treatment, guidelines emphasize two patient care priorities: (1) immediate hemorrhage control and (2) early resuscitation with whole blood or blood products. The LifeFlow device is designed to rapidly infuse blood products. However, the effects of using this device compared to pressure-bag systems remain unclear. We hypothesize that there will be no laboratory-measured difference with the blood when infused through the LifeFlow versus the current standard pressure bag system.

METHODS

Two units of fresh whole blood were obtained from a sus scrofa model. One unit was "infused" using the LifeFlow with the other unit used as a control through a standard pressure bag system into an empty bag. The "before" measurements were obtained from blood samples from a standard fresh whole blood collection bag. The blood was "infused" into a whole blood bag devoid of storage solution from which the "after" measurements were obtained.

RESULTS

This study utilized 22 clinically healthy sus scrofa. Blood units were primarily obtained from a left subclavian central line (50.0%). The median time to acquire and administer a unit of blood was similar for both the LifeFlow device (8.4 min and 8.1 min) and the pressure bag (8.7 min and 7.4 min). No significant differences were found in the total time to acquire or administer blood between the two devices. The median volume of blood acquired was 500 mL for both groups. While no significant differences in blood parameters were observed between the two devices, significant differences were noted when comparing pre- and post-transfusion values within each device. For the LifeFlow device, an increase in hemoglobin and chloride levels and a decrease in thromboplastin time and glucose levels were observed. With the pressure bag, only a decrease in blood urea nitrogen was observed.

CONCLUSIONS

In comparing the LifeFlow to the pressure bag, there were no significant differences noted in the total time to acquire or administer a whole unit of blood. However, there were differences with several laboratory parameters of unclear clinical significance.

Commentary on gaps in prehospital trauma care: education and bioengineering innovations to improve outcomes in hemorrhage and traumatic brain injury

Hemorrhage remains the leading cause of preventable death on the battlefield and the civilian arena. Many of these deaths occur in the prehospital setting. Traumatic brain injury also represents a major source of early mortality and morbidity in military and civilian settings. The inaugural HERETIC (HEmostatic REsuscitation and Trauma Induced Coagulopathy) Symposium convened a multidisciplinary panel of experts in prehospital trauma care to discuss what education and bioengineering advancements in the prehospital space are necessary to improve outcomes in hemorrhagic shock and traumatic brain injury. The panel identified several promising technological breakthroughs, including field point-of-care diagnostics for hemorrhage and brain injury and unique hemorrhage control options for non-compressible torso hemorrhage. Many of these technologies exist but require further advancement to be feasibly and reliably deployed in a prehospital or combat environment. The panel discussed shifting educational and training paradigms to clinical immersion experiences, particularly for prehospital clinicians. The panel discussed an important balance between pushing traditionally hospital-based interventions into the field and developing novel intervention options specifically for the prehospital environment. Advancing prehospital diagnostics may be important not only to allow more targeted applications of therapeutic options, but also to identify patients with less urgent injuries that may not need more advanced diagnostics, interventions, or transfer to a higher level of care in resource-constrained environments. Academia and industry should partner and prioritize some of the promising advances identified with a goal to prepare them for clinical field deployment to optimize the care of patients near the point of injury.

Casualty evacuation in arctic and extreme cold environments: A paradigm shift for traumatic hypothermia management in tactical combat casualty care

In Arctic or extreme cold environments of Alaska, trauma care is complicated by large expanses of geography and lack of forward-positioned resources. This paper presents four hypothetical vignettes highlighting austere cold medical priorities: (1) traumatic hypothermia management as part of Tactical Combat Casualty Care (TCCC) is clinically and tactically important and hypothermia needs to be reprioritized in the MARCH algorithm to MhARCH; (2) at present it is unknown which TCCC recommended medical equipment/supplies will function as designed in the extreme cold; (3) ensuring advanced resuscitative care measures are available serves as a temporal bridge until casualties can receive damage control resuscitation (DCR); and (4) current systems for managing traumatic hypothermia in TCCC and casualty evacuation (CASEVAC) are insufficient. In conclusion, numerous assessments recognise the DoD's current solutions for employing medical forces in Arctic operations are not optimally postured to save lives. There should be a joint standard for fielding an arctic supplement to current medical equipment sets. A new way of thinking in terms of an "ecosystem" approach of immediate casualty protection and movement in CASEVAC doctrine is needed to optimise these "Golden Minutes."

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

BACKGROUND

Transfusion studies in civilian trauma patients have tried to identify a general futility threshold. We hypothesized that in combat settings there is no general threshold where blood product transfusion becomes unbeneficial to survival in hemorrhaging patients. We sought to assess the relationship between the number of units of blood products transfused and 24-hour mortality in combat casualties.

METHODS

A retrospective analysis of the Department of Defense Trauma Registry supplemented with data from the Armed Forces Medical Examiner. Combat casualties who received at least one unit of blood product at US military medical treatment facilities (MTFs) in combat settings (2002-2020) were included. The main intervention was the total units of any blood product transfused, which was measured from the point of injury until 24 hours after admission from the first deployed MTF. The primary outcome was discharge status (alive, dead) at 24 hours from time of injury.

RESULTS

Of 11,746 patients included, the median age was 24 years, and most patients were male (94.2%) with penetrating injury (84.7%). The median injury severity score was 17 and 783 (6.7%) patients died by 24 hours. Median units of blood products transfused was 8. Most blood products transfused were red blood cells (50.2%), followed by plasma (41.1%), platelets (5.5%), and whole blood (3.2%). Among the 10 patients who received the most units of blood product (164 units to 290 units), 7 survived to 24 hours. The maximum amount of total blood products transfused to a patient who survived was 276 units. Of the 58 patients who received over 100 units of blood product, 20.7% died by 24 hours.

CONCLUSION

While civilian trauma studies suggest the possibility of futility with ultra-massive transfusion, we report that the majority (79.3%) of combat casualties who received transfusions greater than 100 units survived to 24 hours. These results do not support a threshold for futility of blood product transfusion. Further analysis as to predictors for mortality will help in situations of blood product and resource constraints.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Whole blood transfusion in the treatment of acute hemorrhage, a systematic review and meta-analysis

BACKGROUND

Whole blood (WB) transfusion received renewed interest after recent armed conflicts. The effectiveness as compared with blood component transfusion (BCT) is, however, still topic of debate. Therefore, this study investigated the effect of WB ± BCT as compared with BCT transfusion on survival in trauma patients with acute hemorrhage.

METHODS

Studies published up to January 16, 2023, including patients with traumatic hemorrhage comparing WB ± BCT and BCT were included in meta-analysis. Subanalyses were performed on the effectiveness of WB in the treatment of civilian or military trauma patients, patients with massive hemorrhage and on platelet (PLT)/red blood cell (RBC), plasma/RBC and WB/RBC ratios. Methodological quality of studies was interpreted using the Cochrane risk of bias tool. The study protocol was registered in PROSPERO under number CRD42022296900.

RESULTS

Random effect pooled odds ratio (OR) for 24 hours mortality in civilian and military patients treated with WB as compared with BCT was 0.72 (95% confidence interval [CI], 0.53-0.97). In subanalysis of studies conducted in civilian setting (n = 20), early (4 hours, 6 hours, and emergency department) and 24 hours mortality was lower in WB groups compared with BCT groups (OR, 0.65; 95% CI, 0.44-0.96 and OR, 0.71; 95% CI, 0.52-0.98). No difference in late mortality (28 days, 30 days, in-hospital) was found. In military settings (n = 7), there was no difference in early, 24 hours, or late mortality between groups. The WB groups received significant higher PLT/RBC ( p = 0.030) during early treatment and significant higher PLT/RBC and plasma/RBC ratios during 24 hours of treatment ( p = 0.031 and p = 0.007). The overall risk of bias in the majority of studies was judged as serious due to serious risk on confounding and selection bias, and unclear information regarding cointerventions.

CONCLUSION

Civilian trauma patients with acute traumatic hemorrhage treated with WB ± BCT as compared to BCT had lower odds on early and 24-hour mortality. In addition, WB transfusion resulted in higher PLT/RBC and plasma/RBC ratios.

LEVEL OF EVIDENCE

Systematic Review and Meta-Analysis; Level III.

Advances in trauma care to save lives from traumatic injury: A narrative review

ABSTRACT

Recent advances on trauma management from the prehospital setting to in hospital care led to a better surviving severe trauma rate. Mortality from exsanguination remains the first preventable mortality. Damage-control resuscitation and surgery are evolving and thus some promising concepts are developing. Transfusion toolkit is brought on the prehospital scene while temporary bridge to hemostasis may be helpful. Panel transfusion products allow an individualized ratio assumed by fresh frozen or lyophilized plasma, fresh or cold-stored whole blood, fibrinogen, four-factor prothrombin complex concentrates. Growing interest is raising in whole blood transfusion, resuscitative endovascular balloon occlusion of the aorta use, hybrid emergency room, viscoelastic hemostatic assays to improve patient outcomes. Microcirculation, traumatic endotheliopathy, organ failures and secondary immunosuppression are point out since late deaths are increasing and may deserve specific treatment.As each trauma patient follows his own course over the following days after trauma, trauma management may be seen through successive, temporal, and individualized aims.

Time to Whole Blood Transfusion in Hemorrhaging Civilian Trauma Patients: There Is Always Room for Improvement

BACKGROUND

Whole blood (WB) is becoming the preferred product for the resuscitation of hemorrhaging trauma patients. However, there is a lack of data on the optimum timing of receiving WB. We aimed to assess the effect of time to WB transfusion on the outcomes of trauma patients.

STUDY DESIGN

The American College of Surgeons TQIP 2017 to 2019 database was analyzed. Adult trauma patients who received at least 1 unit of WB within the first 2 hours of admission were included. Patients were stratified by time to first unit of WB transfusion (first 30 minutes, second 30 minutes, and second hour). Primary outcomes were 24-hour and in-hospital mortality, adjusting for potential confounders.

RESULTS

A total of 1,952 patients were identified. Mean age and systolic blood pressure were 42 ± 18 years and 101 ± 35 mmHg, respectively. Median Injury Severity Score was 17 [10 to 26], and all groups had comparable injury severities (p = 0.27). Overall, 24-hour and in-hospital mortality rates were 14% and 19%, respectively. Transfusion of WB after 30 minutes was progressively associated with increased adjusted odds of 24-hour mortality (second 30 minutes: adjusted odds ratio [aOR] 2.07, p = 0.015; second hour: aOR 2.39, p = 0.010) and in-hospital mortality (second 30 minutes: aOR 1.79, p = 0.025; second hour: aOR 1.98, p = 0.018). On subanalysis of patients with an admission shock index >1, every 30-minute delay in WB transfusion was associated with higher odds of 24-hour (aOR 1.23, p = 0.019) and in-hospital (aOR 1.18, p = 0.033) mortality.

CONCLUSIONS

Every minute delay in WB transfusion is associated with a 2% increase in odds of 24-hour and in-hospital mortality among hemorrhaging trauma patients. WB should be readily available and easily accessible in the trauma bay for the early resuscitation of hemorrhaging patients.

An observational study of the blood use in combat casualties of the French Armed Forces, 2013-2021

BACKGROUND

The French Armed Forces conduct asymmetric warfare in the Sahara-Sahel Strip. Casualties are treated with damage control resuscitation to the extent possible. Questions remain about the feasibility and sustainability of using blood for wider use in austere environments.

METHODS

We performed a retrospective analysis of all French military trauma patients transfused after injury in overseas military operations in Sahel-Saharan Strip, from the point of injury, until day 7, between January 11, 2013 to December 31, 2021.

RESULTS

Forty-five patients were transfused. Twenty-three (51%) of them required four red blood cells units (RBC) or more in the first 24H defining a severe hemorrhage. The median blood product consumption within the first 48 h, was 8 (IQR [3; 18]) units of blood products (BP) for all study population but up to 17 units (IQR [10; 27.5]) for the trauma patients with severe hemorrhage. Transfusion started at prehospital stage for 20 patients (45%) and included several blood products: French lyophilized plasma, RBCs, and whole blood. Patients with severe hemorrhage required a median of 2 [IQR 0; 34] further units of BP from day 3 to day 7 after injury. Eight patients died in theater, 4 with severe hemorrhage and these 4 used an average of 12 products at Role 1 and 2.

CONCLUSION

The transfusion needs were predominant in the first 48 h after the injury but also continued throughout the first week for the most severe trauma patients. Importantly, our study involved a low-intensity conflict, with a small number of injured combatants.

Pediatric traumatic hemorrhagic shock consensus conference research priorities

BACKGROUND

Traumatic injury is the leading cause of death in children and adolescents. Hemorrhagic shock remains a common and preventable cause of death in the pediatric trauma patients. A paucity of high-quality evidence is available to guide specific aspects of hemorrhage control in this population. We sought to identify high-priority research topics for the care of pediatric trauma patients in hemorrhagic shock.

METHODS

A panel of 16 consensus multidisciplinary committee members from the Pediatric Traumatic Hemorrhagic Shock Consensus Conference developed research priorities for addressing knowledge gaps in the care of injured children and adolescents in hemorrhagic shock. These ideas were informed by a systematic review of topics in this area and a discussion of these areas in the consensus conference. Research priorities were synthesized along themes and prioritized by anonymous voting.

RESULTS

Eleven research priorities that warrant additional investigation were identified by the consensus committee. Areas of proposed study included well-designed clinical trials and evaluations, including increasing the speed and accuracy of identifying and treating hemorrhagic shock, defining the role of whole blood and tranexamic acid use, and assessment of the utility and appropriate use of viscoelastic techniques during early resuscitation. The committee recommended the need to standardize essential definitions, data elements, and data collection to facilitate research in this area.

CONCLUSION

Research gaps remain in many areas related to the care of hemorrhagic shock after pediatric injury. Addressing these gaps is needed to develop improved evidence-based recommendations for the care of pediatric trauma patients in hemorrhagic shock.

Use of Cold-Stored Whole Blood is Associated with Improved Mortality in Hemostatic Resuscitation of Major Bleeding: A Multicenter Study

OBJECTIVE

The aim of this study was to identify a mortality benefit with the use of whole blood as part of the resuscitation of bleeding trauma patients.

SUMMARY BACKGROUND DATA

Blood component therapy (BCT) is the current standard for resuscitating trauma patients, with whole blood (WB) emerging as the blood product of choice. We hypothesized that the use of WB versus BCT alone would result in decreased mortality.

METHODS

We performed a 14-center, prospective-observational study of trauma patients who received WB versus BCT during their resuscitation. We applied a generalized linear mixed-effects model with a random effect and controlled for age, sex, mechanism of injury (MOI), and injury severity score (ISS). All patients who received blood as part of their initial resuscitation were included. Primary outcome was mortality and secondary outcomes included AKI, DVT/PE, pulmonary complications, and bleeding complications.

RESULTS

A total of 1,623 (WB: 1,180(74%), BCT: 443(27%)) patients who sustained penetrating (53%) or blunt (47%) injury were included. Patients who received WB had a higher shock index (0.98 vs. 0.83), more comorbidities, and more blunt MOI (all P<0.05). After controlling for center, age, sex, MOI, and ISS, we found no differences in the rates of AKI, DVT/PE or pulmonary complications. WB patients were 9% less likely to experience bleeding complications and were 48% less likely to die than BCT patients (P<0.0001).

CONCLUSIONS

Compared with BCT, the use of WB was associated with a 48% reduction in mortality in trauma patients. Our study supports the use of WB use in the resuscitation of trauma patients.

Characterization of Humanitarian Trauma Care by US Military Facilities During Combat Operations in Afghanistan and Iraq

OBJECTIVE

To characterize humanitarian trauma care delivered by US military treatment facilities (MTFs) in Afghanistan and Iraq during combat operations.

BACKGROUND

International Humanitarian Law, which includes the Geneva Conventions, defines protections and standards of treatment to victims of armed conflicts. In 1949 these standards expanded to include injured civilians. In 2001, the Global War on Terror began in Afghanistan and expanded to Iraq in 2003. US MTFs provided care to all military forces, civilians, and enemy prisoners. A thorough understanding of the scope, epidemiology, resource requirements and outcomes of civilian trauma in combat zones has not been previously characterized.

METHODS

Retrospective cohort analysis of the Department of Defense Trauma Registry from 2005-2019. Inclusion criteria were civilians and non-NATO coalition personnel (NNCP) with traumatic injuries treated at MTFs in Afghanistan and Iraq. Patient demographics, mechanism of injury, resource requirements, procedures, and outcomes were categorized.

RESULTS

A total of 29,963 casualties were eligible from the Registry. There were 16,749 (55.9%) civilians and 13,214 (44.1%) NNCP. The majority of patients were age >13 years [26,853 (89.6%)] and male [28,000 (93.4%)]. Most injuries were battle-related: 12,740 (76.1%) civilians and 11,099 (84.0%) NNCP. Penetrating trauma was the most common cause of both battle and nonbattle injuries: 12,293 (73.4%) civilian and 10,029 (75.9%) NNCP. Median injury severity score (ISS) was 9 in each cohort with ISS scores ≥ 25 in 2,236 (13.4%) civilians and 1,398 (10.6%) NNCP. Blood products were transfused to 35% of each cohort: 5,850 civilians received a transfusion with 2,118 (12.6%) of them receiving ≥10 units; 4,590 NNCPs received a transfusion with 1,669 (12.6%) receiving ≥ 10 units. MTF mortality rates were civilians 1,263 (7.5%) and NNCP 776 (5.9%). Interventions, both operative and non-operative, were similar between both groups.

CONCLUSIONS

In accordance with International Humanitarian Law, as well as the US military's medical rules of eligibility, civilians injured in combat zones were provided the same level of care as non-NATO Coalition Personnel. Injured civilians and NNCP had similar mechanisms of injury, injury patterns, transfusion needs, and ISS. This analysis demonstrates resource equipoise in trauma care delivered to civilians and NNCP. Hospitals in combat zones must be prepared to manage large numbers of civilian casualties with significant human and material resources allocated to optimize survival. The provision of humanitarian trauma care is resource-intensive, and these data can be used to inform planning factors for current or future humanitarian care in combat zones.

The U.S. Armed Services Blood Program support to U.S. Central Command 2014-2021: Transformation of combat trauma resuscitation through blood product innovation and expansion of blood availability far forward

BACKGROUND

The United States Armed Services Blood Program (ASBP) faced complex blood supply challenges during two decades of military operations in the U.S. Central Command (CENTCOM) and through an adaptive, responsive, and agile system, gained valuable insights on blood product usage in combat casualty care.

STUDY DESIGN AND METHODS

A retrospective review of blood product introduction and utilization trends was compiled from ASBP data collected during CENTCOM operations from 2014 through 2021.

RESULTS

During the study period, several blood products were introduced to the CENTCOM area of operations including Low Titer O Whole Blood (LTOWB), Cold-Stored Platelets (CSP), Liquid Plasma (LP), and French Freeze Dried Plasma (FDP) manufactured from U.S. sourced donor plasma, all while expanding Walking Blood Bank capabilities. There was a gradual substitution of component therapy for whole blood; blood utilization peaked in 2017. Transfusion of Fresh Whole Blood (FWB) from Walking Blood Banks decreased as fully pre-tested LTOWB was supplied by the ASBP. LTOWB was initially supplied in citrate-phosphate-dextrose (CPD) anticoagulant (21-day shelf life) but was largely replaced with LTOWB in citrate-phosphate-dextrose-adenine (CPDA-1) anticoagulant (35-day shelf life) by 2019. Implementation of prehospital transfusion and expansion of surgical and resuscitation teams led to an increase in the number of sites receiving blood.

DISCUSSION

ASBP introduced new products to its inventory in order to meet changing blood product demands driven by changes in the Joint Trauma System Clinical Practice Guidelines and operational demands. These products were adopted into clinical practice with a resultant evolution in transfusion strategies.

Determining Resuscitation Outcomes in Combat Casualties: Design of the Deployed Hemostatic Emergency Resuscitation Of Traumatic Exsanguinating Shock (Deployed HEROES) Study

BACKGROUND

During the course of the recent conflicts, the recommendations for resuscitation practices have evolved, but there has been no comprehensive comparative effectiveness study of these resuscitation strategies. The objective of this study was to describe the development and study design of the Deployed Hemostatic Emergency Resuscitation Of Traumatic Exsanguinating Shock (Deployed HEROES) Study- the first comprehensive analysis of military resuscitation practices in the deployed environment from October 2001 to October 2019.

METHODS

This retrospective cohort study uses the DoD Trauma Registry, Armed Services Blood Program database, and Military Trauma Mortality Review, while abstractors will use Theater Medical Data Store and Web Interface Patient Records to collect transfusion timing data. This study includes patients, who received blood products or died before receiving blood, treated at US military medical treatment facilities. The primary endpoints are survival at 6 hours, 24 hours, and 30 days post-injury. Secondary outcomes include infection, renal dysfunction, pulmonary dysfunction, and thromboembolic event. Exposure will be defined by blood product transfusion. Study groups will be frequency-matched. Cox proportional hazards will compare patients who received WFWB, LTOWB, or only component therapy, while using adjustment for type of blood product transfused as a time-dependent covariate. Multilevel mixed-effects logistic regression will determine the effect of incompatible plasma in LTOWB.

RESULTS

An analysis plan for the Deployed HEROES study was developed with the aim of minimizing bias.

CONCLUSIONS

This study will inform the optimal resuscitation strategies, which will potentially have a substantial impact on combat mortality. If whole blood is found to be the optimal transfusion strategy, this finding will be crucial in future operating environments involving dispersed medical assets. These results will provide critical information necessary for combat casualty care guidelines.

LEVEL OF EVIDENCE

Level III.

The Role of Whole Blood Transfusions in Civilian Trauma: A Review of Literature in Military and Civilian Trauma

Resuscitation techniques for the management of adult trauma patients have evolved over the 20th century. Whole blood transfusions were previously used as the standard of care, whereas blood component therapy is the current method employed across most trauma centers across the United States. Prior to the transition, no studies were conducted to show improved efficacy of hemostatic potential in trauma patients. Recent conflicts in Iraq and Afghanistan have challenged the dogma that whole blood transfusions are not the standard of care and have shown potential as the superior transfusion product for adult trauma patients. The purpose of this review is to provide a comprehensive review and elucidate if whole blood transfusions have a role in civilian trauma patients based upon recent military medical literature and civilian pilot studies using whole blood transfusions.

The Story of Blood for Shock Resuscitation: How the Pendulum Swings

Whole blood transfusion (WBT) began in 1667 as a treatment for mental illness, with predictably poor results. Its therapeutic utility and widespread use were initially limited by deficiencies in transfusion science and antisepsis. James Blundell, a British obstetrician, was recognized for the first allotransfusion in 1825. However, WBT did not become safe and therapeutic until the early 20th century, with the advent of reliable equipment, sterilization, and blood typing. The discovery of citrate preservation in World War I allowed a separation of donor from recipient and introduced the practice of blood banking. During World War II, Elliott and Strumia were the first to separate whole blood into blood component therapy (BCT), producing dried plasma as a resuscitative product for "traumatic shock." During the 1970s, infectious disease, blood fractionation, and financial opportunities further drove the change from WBT to BCT, with few supporting data. Following a period of high-volume crystalloid and BCT resuscitation well into the early 2000s, measures to avoid the resulting iatrogenic resuscitation injury were developed under the concept of damage control resuscitation. Modern transfusion strategies for hemorrhagic shock target balanced BCT to reapproximate whole blood. Contemporary research has expanded the role of WBT to therapy for the acute coagulopathy of trauma and the damaged endothelium. Many US trauma centers are now using WBT as a front-line treatment in tandem with BCT for patients suffering hemorrhagic shock. Looking ahead, it is likely that WBT will once again be the resuscitative fluid of choice for patients in hemorrhagic shock.