Low titer group O whole blood resuscitation: Military experience from the point of injury

A Review of 75th Ranger Regiment Battle-Injured Fatalities Incurred During Combat Operations From 2001 to 2021

INTRODUCTION

The 75th Ranger Regiment is an elite U.S. military special operations unit that conducted over 20 years of sustained combat operations. The Regiment has a history of providing novel and cutting-edge prehospital trauma care, advancing and translating medical initiatives, and documenting and reporting casualty care performance improvement efforts.

MATERIALS AND METHODS

A retrospective case fatality rate (CFR) review, mortality review, and descriptive analysis of fatalities were conducted for battle-injured personnel assigned or attached to the 75th Ranger Regiment from 2001 to 2021 during combat operations primarily in Afghanistan and Iraq. Fatalities were evaluated for population characteristics, cause of death, mechanism of death, injury severity, injury survivability, and death preventability.

RESULTS

A total of 813 battle injury casualties, including 62 fatalities, were incurred over 20 years and 1 month of continuous combat operations. The Regiment maintained a zero rate of prehospital preventable combat death. Additionally, no fatalities had a mechanism of death because of isolated extremity hemorrhage, tension pneumothorax, or airway obstruction. When comparing the CFR of the Regiment to the U.S. military population as a whole, the Regiment had a significantly greater reduction in the cumulative CFR as measured by the difference in average annual percentage change.

CONCLUSIONS

Documentation and analysis of casualties and care, mortality and casualty reviews, and other performance improvement efforts can guide combatant commanders, medical directors, and fighting forces to reduce preventable combat deaths and the CFR. Early hemorrhage control, blood product resuscitation, and other lifesaving interventions should be established and maintained as a standard prehospital practice to mitigate fatalities with potentially survivable injuries.

Advanced Critical Care Techniques in the Field

Critical care principles and techniques continue to hold promise for improving patient outcomes in time-dependent diseases encountered by emergency medical services such as cardiac arrest, acute ischemic stroke, and hemorrhagic shock. In this review, the authors discuss several current and evolving advanced critical care modalities, including extracorporeal cardiopulmonary resuscitation, resuscitative endovascular occlusion of the aorta, prehospital thrombolytics for acute ischemic stroke, and low-titer group O whole blood for trauma patients. Two important critical care monitoring technologies-capnography and ultrasound-are also briefly discussed.

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.

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.

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.

Casualty care implications of large-scale combat operations

Analysis and review of combat casualty care challenges in future large-scale and medical multi-domain operations from the perspective of past, present, and potential future conflicts.

Adherence to a Balanced Approach to Massive Transfusion in Combat Casualties

BACKGROUND

Hemorrhage is the most common cause of potentially preventable death on the battlefield. Balanced resuscitation with plasma, platelets, and packed red blood cells (PRBCs) in a 1:1:1 ratio, if whole blood (WB) is not available, is associated with optimal outcomes among patients with hemorrhage. We describe the use of balanced resuscitation among combat casualties undergoing massive transfusion.

MATERIALS AND METHODS

We conducted a secondary analysis of data from the Department of Defense Trauma Registry (DODTR) spanning encounters from January 1, 2007, to March 17, 2020. We included all casualties who received at least 10 units of either PRBCs or WB. We categorized casualties as recipients of plasma-balanced resuscitation if the ratio of plasma to PRBC units was 0.8 or greater; similarly, we defined platelet-balanced resuscitation as a ratio of platelets to PRBC units of 0.8 or greater. We portrayed these populations using descriptive statistics and compared characteristics between non-balanced and balanced resuscitation recipients for both plasma and platelets.

RESULTS

We identified 28,950 encounters in the DODTR with documentation of prehospital activity. Massive transfusions occurred for 2,414 (8.3%) casualties, among whom 1,593 (66.0%) received a plasma-balanced resuscitation and 1,248 (51.7%) received a platelet-balanced resuscitation. During the study period, 962 (39.8%) of these patients received a fully balanced resuscitation with regard to both the plasma:PRBC and platelet:PRBC ratios. The remaining casualties did not undergo a balanced resuscitation.

CONCLUSIONS

While a majority of massive transfusion recipients received a plasma-balanced and/or platelet-balanced resuscitation, fewer patients received a platelet-balanced resuscitation. These findings suggest that more emphasis in training and supply may be necessary to optimize blood product resuscitation ratios.

Effects of hemodilution on coagulation function during prolonged hypotensive resuscitation in a porcine model of severe hemorrhagic shock

Background

Although hemorrhage remains the leading cause of survivable death in casualties, modern conflicts are becoming more austere limiting available resources to include resuscitation products. With limited resources also comes prolonged evacuation time, leaving suboptimal prehospital field care conditions. When blood products are limited or unavailable, crystalloid becomes the resuscitation fluid of choice. However, there is concern of continuous crystalloid infusion during a prolonged period to achieve hemodynamic stability for a patient. This study evaluates the effect of hemodilution from a 6-hour prehospital hypotensive phase on coagulation in a porcine model of severe hemorrhagic shock.

Methods

Adult male swine (n=5/group) were randomized into three experimental groups. Non-shock (NS)/normotensive did not undergo injury and were controls. NS/permissive hypotensive (PH) was bled to the PH target of systolic blood pressure (SBP) 85±5 mm Hg for 6 hours of prolonged field care (PFC) with SBP maintained via crystalloid, then recovered. Experimental group underwent controlled hemorrhage to mean arterial pressure 30 mm Hg until decompensation (Decomp/PH), followed by PH resuscitation with crystalloid for 6 hours. Hemorrhaged animals were then resuscitated with whole blood and recovered. Blood samples were collected at certain time points for analysis of complete blood counts, coagulation function, and inflammation.

Results

Throughout the 6-hour PFC, hematocrit, hemoglobin, and platelets showed significant decreases over time in the Decomp/PH group, indicating hemodilution, compared with the other groups. However, this was corrected with whole blood resuscitation. Despite the appearance of hemodilution, coagulation and perfusion parameters were not severely compromised.

Conclusions

Although significant hemodilution occurred, there was minimal impact on coagulation and endothelial function. This suggests that it is possible to maintain the SBP target to preserve perfusion of vital organs at a hemodilution threshold in resource-constrained environments. Future studies should address therapeutics that can mitigate potential hemodilutional effects such as lack of fibrinogen or platelets.

Level of evidence

Not applicable-Basic Animal Research.

Transfusion management in the trauma patient

PURPOSE OF REVIEW

Transfusion of blood products is lifesaving in the trauma ICU. Intensivists must be familiar with contemporary literature to develop the optimal transfusion strategy for each patient.

RECENT FINDINGS

A balanced ratio of red-blood cells to plasma and platelets is associated with improved mortality and has therefore become the standard of care for resuscitation. There is a dose-dependent relationship between units of product transfused and infections. Liquid and freeze-dried plasma are alternatives to fresh frozen plasma that can be administered immediately and may improve coagulation parameters more rapidly, though higher quality research is needed. Trauma induced coagulopathy can occur despite a balanced transfusion, and administration of prothrombin complex concentrate and cryoprecipitate may have a role in preventing this. In addition to balanced ratios, viscoelastic guidance is being increasingly utilized to individualize component transfusion. Alternatively, whole blood can be used, which has become the standard in military practice and is gaining popularity at civilian centers.

SUMMARY

Hemorrhagic shock is the leading cause of death in trauma. Improved resuscitation strategy has been one of the most important contemporary advancements in trauma care and continues to be a key area of clinical research.

Prehospital Use of Whole Blood for Ill and Injured Patients During Critical Care Transport

OBJECTIVE

Hemodynamic instability and hemorrhagic shock are frequently encountered by emergency medical services providers managing ill and injured patients during critical care transport. Although many critical care transport services commonly transfuse crystalloids and/or packed red blood cells (PRBCs), the administration of whole blood (WB) in prehospital care is currently limited. WB contains PRBCs, plasma, and platelets in a physiologic ratio to aid in oxygen delivery to tissue as well as hemostasis. This study describes a single critical care transport program's experience using WB for critically ill and injured patients and reports important clinical and safety outcomes.

METHODS

This study was a retrospective review of patients who were transported by a single rotor wing-based critical care transport service to 1 of 2 tertiary care receiving hospitals within a single health system. Patients who were transported between November 1, 2018, and November 30, 2019, and who received at least 1 unit of low-titer group O WB during critical care transport were included. The primary outcomes of interest included 24-hour mortality and the total 24-hour transfusion requirement. The safety outcomes included transfusion reactions, acute lung injury, acute kidney injury, and the incidence of venous thromboembolism.

RESULTS

During the study period, there were 3,084 total patients transported by our critical care transport service. There were 71 patients who received prehospital WB, 64 of whom met the inclusion criteria. The top 3 indications for WB administration included blunt trauma (n = 27, 42.2%), gastrointestinal hemorrhage (n = 15, 23.4%), and penetrating trauma (n = 11, 17.2%). The median total number of blood components transfused within 24 hours was 4.0 (interquartile range, 2.0-9.5), and the overall 24-hour mortality rate was 21.9%.

CONCLUSIONS

The administration of WB by emergency medical services providers to critically ill and injured patients in the prehospital setting is feasible and is associated with low incidences of adverse events and transfusion reactions. Further research is needed to elucidate the benefits of WB relative to current prehospital standards of care.

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.

The Use of Whole Blood Transfusion in Trauma

Purpose of Review

This review illustrates the current benefits, limitations, ongoing research, and future paths for Low Titer O Whole Blood compared to Component Therapy in massive transfusion for trauma patients.

Recent Findings

Many studies show that compared to Component Therapy, Low Titer O Whole Blood transfusion is associated with better patient outcomes and simplified transfusion logistics among others. There are, however, issues with cost, supply/demand and handling of Whole Blood that limit its use, but experience in the military setting has shown that these limitations can be easily overcome.

Summary

The use of Whole Blood has increased in the civilian trauma population and there is a growing body of evidence to support its current use. More research looking at Whole Blood in females of child-bearing age, pediatric populations, and cold-stored platelets is underway.

Hemorrhagic Resuscitation Guided by Viscoelastography in Far-Forward Combat and Austere Civilian Environments: Goal-Directed Whole-Blood and Blood-Component Therapy Far from the Trauma Center

Modern approaches to resuscitation seek to bring patient interventions as close as possible to the initial trauma. In recent decades, fresh or cold-stored whole blood has gained widespread support in multiple settings as the best first agent in resuscitation after massive blood loss. However, whole blood is not a panacea, and while current guidelines promote continued resuscitation with fixed ratios of blood products, the debate about the optimal resuscitation strategy-especially in austere or challenging environments-is by no means settled. In this narrative review, we give a brief history of military resuscitation and how whole blood became the mainstay of initial resuscitation. We then outline the principles of viscoelastic hemostatic assays as well as their adoption for providing goal-directed blood-component therapy in trauma centers. After summarizing the nascent research on the strengths and limitations of viscoelastic platforms in challenging environmental conditions, we conclude with our vision of how these platforms can be deployed in far-forward combat and austere civilian environments to maximize survival.

Pathophysiology of Hemorrhage as It Relates to the Warfighter

Saving lives of wounded military Warfighters often depends on the ability to resolve or mitigate the pathophysiology of hemorrhage, specifically diminished oxygen delivery to vital organs that leads to multi-organ failure and death. However, caring for hemorrhaging patients on the battlefield presents unique challenges that extend beyond applying a tourniquet and giving a blood transfusion, especially when battlefield care must be provided for a prolonged period. This review will describe these challenges and potential strategies for treating hemorrhage on the battlefield in a prolonged casualty care situation.

Prehospital whole blood reduces early mortality in patients with hemorrhagic shock

BACKGROUND

Low titer O+ whole blood (LTOWB) is being increasingly used for resuscitation of hemorrhagic shock in military and civilian settings. The objective of this study was to identify the impact of prehospital LTOWB on survival for patients in shock receiving prehospital LTOWB transfusion.

STUDY DESIGN AND METHODS

A single institutional trauma registry was queried for patients undergoing prehospital transfusion between 2015 and 2019. Patients were stratified based on prehospital LTOWB transfusion (PHT) or no prehospital transfusion (NT). Outcomes measured included emergency department (ED), 6-h and hospital mortality, change in shock index (SI), and incidence of massive transfusion. Statistical analyses were performed.

RESULTS

A total of 538 patients met inclusion criteria. Patients undergoing PHT had worse shock physiology (median SI 1.25 vs. 0.95, p < .001) with greater reversal of shock upon arrival (-0.28 vs. -0.002, p < .001). In a propensity-matched group of 214 patients with prehospital shock, 58 patients underwent PHT and 156 did not. Demographics were similar between the groups. Mean improvement in SI between scene and ED was greatest for patients in the PHT group with a lower trauma bay mortality (0% vs. 7%, p = .04). No survival benefit for patients in prehospital cardiac arrest receiving LTOWB was found (p > .05).

DISCUSSION

This study demonstrated that trauma patients who received prehospital LTOWB transfusion had a greater improvement in SI and a reduction in early mortality. Patient with prehospital cardiac arrest did not have an improvement in survival. These findings support LTOWB use in the prehospital setting. Further multi-institutional prospective studies are needed.

Hemorrhagic shock and hemostatic resuscitation in canine trauma

Hemorrhage is a significant cause of death among military working dogs and in civilian canine trauma. While research specifically aimed at canine trauma is limited, many principles from human trauma resuscitation apply. Trauma with significant hemorrhage results in shock and inadequate oxygen delivery to tissues. This leads to aberrations in cellular metabolism, including anaerobic metabolism, decreased energy production, acidosis, cell swelling, and eventual cell death. Considering blood and endothelium as a single organ system, blood failure is a syndrome of endotheliopathy, coagulopathy, and platelet dysfunction. In severe cases following injury, blood failure develops and is induced by inadequate oxygen delivery in the presence of hemorrhage, tissue injury, and acute stress from trauma. Severe hemorrhagic shock is best treated with hemostatic resuscitation, wherein blood products are used to restore effective circulating volume and increase oxygen delivery to tissues without exacerbating blood failure. The principles of hemostatic resuscitation have been demonstrated in severely injured people and the authors propose an algorithm for applying this to canine patients. The use of plasma and whole blood to resuscitate severely injured canines while minimizing the use of crystalloids and colloids could prove instrumental in improving both mortality and morbidity. More work is needed to understand the canine patient that would benefit from hemostatic resuscitation, as well as to determine the optimal resuscitation strategy for these patients.

An analysis of outcomes for pediatric trauma warm fresh whole blood recipients in Iraq and Afghanistan

BACKGROUND

Whole blood therapy-which contains the ideal balance of components, and particularly fresh whole blood-has been shown to be beneficial in adult trauma. It remains unclear whether there is potential benefit in the pediatric population.

STUDY DESIGN AND METHODS

This is a secondary analysis of previously published data analyzing pediatric casualties undergoing massive transfusion in the Department of Defense Trauma Registry. Pediatric patients with traumatic injury who were transfused at least one blood product were included in the analysis. We compared children who received component therapy exclusively to those who received any amount of warm fresh whole blood.

RESULTS

Of the 3439 pediatric casualties within our dataset, 1244 were transfused at least one blood product within the first 24 h. There were 848 patients without severe head injury. Within this cohort, 23 children received warm fresh whole blood overall, 20 of whom did not have severe head injury. In an adjusted analysis, the odds ratio (95% confidence interval [CI]) for survival for warm fresh whole blood recipients was 2.86 (0.40-20.45). After removing children with severe brain injury, there was an independent association with improved survival for warm fresh whole blood recipients with an odds ratio (95% CI) of 58.63 (2.70-1272.67).

DISCUSSION

Our data suggest that warm fresh whole blood may be associated with improved survival in children without severe head injury. Larger prospective studies are needed to assess the efficacy and safety of whole blood in children with severe traumatic bleeding.

Variation of anti-A and anti-B titers in group O potential blood donors: A pilot study

BACKGROUND

Resuscitation with fresh whole blood is vital to preserving life on the battlefield. Transfusing low titer O whole blood (LTOWB), defined as anti-A and anti-B titer levels of <1:256, is safe because LTOWB alleviates the risk for hemolytic transfusion reactions. Because of possible variations in titer levels over time, a study was needed using US Navy and Marine Corps personnel to assess how these titers change across two assessments.

METHODS

Retrospective data from group O marines and sailors (M = 25 years of age; range, 19-35 years) stationed in the San Diego region were acquired from the Armed Services Blood Program and the Composite Health Care System. Of 972 group O donors between January 2016 and November 2019, 55 donors with 2 samples were identified (N = 55). Analysis included contrasting rates of high (≥1:256) and low (<1:256) anti-A and anti-B titers on the initial and second blood tests, along with the time between testings.

RESULTS

The average time between testing was 332 days (range, 35-1,121 days), which far exceeded the recommended 90-day interval (p < 0.00001). Only 45% met the 90-day recommendation. Titer status changed frequently, from low to high (anti-A, 18%; anti-B, 13%; LTOWB to not LTOWB, 21%) or from high to low (anti-A, 62%; anti-B, 78%; not LTOWB to LTOWB, 62%).

CONCLUSIONS

Anti-A and anti-B titers change frequently enough to warrant testing immediately before deployment and even during deployment. The observed time elapsed between testing is unacceptably long. The present pilot study provides a foundation for a larger formal study to more fully characterize titer changes over repeated testing.

LEVEL OF EVIDENCE

Diagnostic test, level IV.

Safety and efficacy of low-titer O whole blood resuscitation in a civilian level I trauma center

BACKGROUND

Military experience has shown low-titer O whole blood (LTOWB) to be safe and beneficial in the resuscitation of hemorrhaging trauma patients. However, few civilian centers use LTOWB for trauma resuscitation. We evaluated the early experience and safety of a LTOWB program at a level 1 civilian trauma center.

METHODS

We retrospectively reviewed our trauma registry from January 2018 to June 2020 for patients admitted in shock (defined as ≥1 of the following: heart rate, >120 beats per minute; systolic blood pressure, <90 mm Hg; or shock index, >0.9) who received blood products within 24 hours. Patients were grouped by resuscitation provided: LTOWB (group 1), component therapy (CT; group 2), and LTOWB-CT (group 3). Safety, outcomes, and variables associated with LTOWB transfusion and mortality were analyzed.

RESULTS

216 patients were included: 34 in Group 1, 95 in Group 2, and 87 in Group 3. Patientsreceiving LTOWB were more commonly male (p<0.001) and had a penetrating injury (p=0.005). Groups 1 and 3 had higher median ISS scores compared to Group 2 (19 and 20 vs 17; p=0.01). Group 3 received more median units of blood product in the first 4h (p<0.001) and in the first 24h (p<0.001). There was no difference between groups in 24h mortality or transfusion-related complications (all p>0.05). Arrival ED SBP was associated with LTOWB transfusion (odds ratio [OR] 0.98, 95% confidence interval [CI] 0.95-1.00, p=0.03). ED lactate was independently associated with 24h mortality. (OR 1.27, CI 1.02-1.58, p=0.03). LTOWB transfusion was not associated with mortality (p=0.49). Abstract.

CONCLUSION

Severely injured patients received LTOWB-CT and more overall product units but had similar 24 h mortality when compared with the LTOWB or CT groups. No increase in transfusion-related complications was seen after LTOWB transfusion. Low-titer O whole blood should be strongly considered in the resuscitation of trauma patients at civilian centers.

LEVEL OF EVIDENCE

Retrospective, therapeutic, level IV.

Blood transfusions in gunshot-wound-related emergency department visits and hospitalizations in the United States

BACKGROUND

The United States (US) leads all high-income countries in gunshot wound (GSW) deaths. However, previous US studies have not evaluated the national blood transfusion utilization patterns in hospitalized GSW patients.

METHODS

Data from 2016 to 2017 were analyzed from the Nationwide Emergency Department Sample (NEDS) and Nationwide Inpatient Sample (NIS), the largest all-payer emergency department (ED) and inpatient databases, respectively. Using stratified probability sampling, weights were applied to generate nationally representative estimates. Multivariable Poisson-regression models were used to estimate prevalence ratios (PR) of blood transfusion.

RESULTS

There were 168,315 ED visits and 58,815 hospitalizations (age = 18-90 years) following a GSW. The majority of hospitalizations were men (88.5%), age 18-24 years (31.8%), and assault-related GSW (51.3%). Blacks had the largest proportion (48.7%) overall of all GSW hospitalizations; Whites accounted for the highest proportion of intentional self-harm injuries (72.4%). Blood transfusions occurred in 12.7% of hospitalizations (12.0% red blood cell [RBC], 4.9% plasma, and 2.5% platelet transfusions). Only 1.9% of cases were associated with transfusion of all three blood components. Hospitalizations with major/extreme severity of illness had significantly higher prevalence of transfusion versus those with mild/moderate severity [crude PR = 4.79 (95%CI:4.15-5.33, p < .001)]. Overall, 8.2% of hospitalizations with GSW died, of whom 26.8% required blood transfusions, which was significantly higher than survivors [crude PR = 2.34 (95%CI:2.10-2.61, p < .001)]. The vast majority (95%) of the transfusions among those who died were within 48 h since admission.

CONCLUSIONS

Gun-related violence is a public health emergency in the US, and GSWs are a source of significant mortality, blood utilization, and health care costs.

Prehospital resuscitation

Traumatic injury is the leading cause of death in young people in the USA. Our knowledge of prehospital resuscitation is constantly evolving and is often informed by research based on military experience. A move toward balanced blood product resuscitation and away from excessive crystalloid use has led to improvements in outcomes for trauma patients. This has been facilitated by new technologies allowing more front-line use of blood products as well as use of tranexamic acid in the prehospital setting. In this article, we review current practices in prehospital resuscitation and the studies that have informed these practices.

Blood Product Administration During the Role 1 Phase of Care: The Prehospital Trauma Registry Experience

BACKGROUND

The majority of combat deaths occur in the prehospital setting. Efforts to increase survival including blood transfusions are made in the prehospital setting. The blood products available in the Role 1 setting include whole blood (WB), red blood cells (RBCs), fresh frozen plasma (FFP), and lyophilized (freeze-dried) plasma (FDP).

METHODS

This is a secondary analysis of a previously published dataset within the Prehospital Trauma Registry (PHTR) from 2003 through May 2019. Deterministic linking was used when possible with the DoD Trauma Registry for outcome data. Descriptive statistics were used to analyze the data.

RESULTS

We identified 1,357 patient encounters in the PHTR. Within that group, 28 patients received a prehospital blood product, with 41 total administrations: WB (18), RBCs (12), FFP (6), FDP (3), and blood not otherwise specified (2). Outcome data were available for 17 of the 28 patients. The median injury severity score was 20, with the thorax being the most frequent seriously injured body region. Most (94%) patients survived to discharge. The median ICU days was 11 (Interquartile Range [IQR] 3-19), and the median hospital days was 19 (IQR 8-29). The average volume (units) of RBCs was 6.0 (95% CI 1.9-10.1), WB 2.8 (95% CI 0.0-5.6), platelets 0.7 (95% CI 0.0-1.4), and FFP 5.0 (95% CI 1.2-8.8).

CONCLUSIONS

The use of prehospital blood products is uncommon in U.S. combat settings. Patients who received blood products sustained severe injuries but had a high survival rate. Given the infrequent but critical use and potentially increased need for adequate prolonged casualty care in future near-peer conflicts, optimizing logistical chain circulation is required.