A Conceptual Framework for Non-Military Investigators to Understand the Joint Roles of Medical Care in the Setting of Future Large Scale Combat Operations

A Narrative Review of Existing and Developing Biomarkers in Acute Traumatic Brain Injury for Potential Military Deployed Use

INTRODUCTION

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in both adult civilian and military populations. Currently, diagnostic and prognostic methods are limited to imaging and clinical findings. Biomarker measurements offer a potential method to assess head injuries and help predict outcomes, which has a potential benefit to the military, particularly in the deployed setting where imaging modalities are limited. We determine how biomarkers such as ubiquitin C-terminal hydrolase-L1 (UCH-L1), glial fibrillary acidic protein (GFAP), S100B, neurofilament light chain (NFL), and tau proteins can offer important information to guide the diagnosis, acute management, and prognosis of TBI, specifically in military personnel.

MATERIALS AND METHODS

We performed a narrative review of peer-reviewed literature using online databases of Google Scholar and PubMed. We included articles published between 1988 and 2022.

RESULTS

We screened a total of 73 sources finding a total of 39 original research studies that met inclusion for this review. We found five studies that focused on GFAP, four studies that focused on UCH-L1, eight studies that focused on tau proteins, six studies that focused on NFL, and eight studies that focused on S100B. The remainder of the studies included more than one of the biomarkers of interest.

CONCLUSIONS

TBI occurs frequently in the military and civilian settings with limited methods to diagnose and prognosticate outcomes. We highlighted several promising biomarkers for these purposes including S100B, UCH-L1, NFL, GFAP, and tau proteins. S100B and UCH-L1 appear to have the strongest data to date, but further research is necessary. The robust data that explain the optimal timing and, more importantly, trending of these biomarker measurements are necessary before widespread application.

Management of Combat Casualties during Aeromedical Evacuation from a Role 2 to a Role 3 Medical Facility

INTRODUCTION

Emergent clinical care and patient movements through the military evacuation system improves survival. Patient management differs when transporting from the point-of-injury (POI) to the first medical treatment facility (MTF) versus transporting from the Role 2 to the Role 3 MTF secondary to care rendered within the MTF, including surgery and advanced resuscitation. The objective of this study was to describe care provided to patients during theater inter-facility transports and compare with pre-hospital transports (POI to first MTF).

MATERIALS AND METHODS

We performed a retrospective chart review of patients with the Role 2 to the Role 3 transports in Afghanistan and Iraq from 2007 to 2016. Data collected included procedures and events at the MTF and during transport. We compared the intra-theater transport data (Role 2 to Role 3) to data from a previous study evaluating pre-hospiital transports (POI to first MTF).

RESULTS

We reviewed the records of 869 Role 2 to Role 3 transport patients. Role 2 to Role 3 transports were longer in duration compared to POI transports (39 minutes vs. 23 minutes) and were more likely to be staffed by advanced personnel (nurses, physician assistants, and physicians) (57% vs. 3%). The sample primarily consisted of military-aged males (mean age 27 years) who suffered from explosive or blunt force injuries. Procedures performed during each phase of care reflected the capabilities of the teams and locations. Pain and cardiac events were more common in POI evacuations compared to the Role 2 to Role 3 transports, but documentation of respiratory events, hemodynamic events, neurologic events, and equipment failure was more common during the Role 2 to Role 3 transports. Survival rates were slightly higher among the Role 2 to Role 3 cohort (98% vs. 95%, difference 3% [95% confidence interval of the difference 1-5%]).

CONCLUSIONS

Inter-facility transports (Role 2 to Role 3) are longer in duration, transport more complex patients, and are staffed by more advanced level provider types compared to transports from POI.

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.

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.

Effectiveness of Mobile Applications for Trauma Care in Combat Casualty Simulations Throughout the Continuum

INTRODUCTION

The U.S. Military uses handwritten documentation throughout the continuum of combat casualty care to document from point-of-injury, during transport and at facilities that provide damage control resuscitation and surgery. Proven impractical due to lack of durability and legibility in arduous tactical environments, we hypothesized that mobile applications would increase accuracy and completeness of documentation in combat casualty simulations.

METHODS

We conducted simulations across this continuum utilizing 10 two-person teams consisting of a Medic and an Emergency or Critical Care Nurse. Participants were randomized to either the paper group or BATDOK and T6 Health Systems mobile application group. Simulations were completed in both the classroom and simulated field environments. All documentation was assessed for speed, completeness, and accuracy.

RESULTS

Participant demographics averaged 10.8 ± 5.2 y of military service and 3.9 ± 0.6 h of training on both platforms. Classroom testing showed a significant increase in completeness (84.2 ± 8.1% versus 77.2 ± 6.9%; P = 0.02) and accuracy (77.6 ± 8.1% versus 68.9 ± 7.5%; P = 0.01) for mobile applications versus paper with no significant difference in overall time to completion (P = 0.19). Field testing again showed a significant increase in completeness (91.6 ± 5.8 % versus 70.0 ± 14.1%; P < 0.01) and accuracy (87.7 ± 7.6% versus 64.1 ± 14.4%; P < 0.01) with no significant difference in overall time to completion (P = 0.44).

CONCLUSIONS

In deployed environments, mobile applications have the potential to improve casualty care documentation completeness and accuracy with minimal additional training. These efforts will assist in meeting an urgent operational need to enable our providers.

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.

Retrospective analysis of tranexamic acid administration in French war-wounded between October 2016 and September 2020

INTRODUCTION

Since 2013, the French Army Health Service, in agreement with international experts, has recommended the administration of 1 g of tranexamic acid (TXA) in trauma patients in haemorrhagic shock or at risk of bleeding within 3 hours of the trauma.

METHODS

The aim of this analysis was to describe the administration of TXA in French military personnel wounded during military operations in the Sahelo-Sahelian band between October 2016 and September 2020. Data were collected from forward health records and hospital data from the French hospital where the casualty was finally evacuated. Underuse of TXA was defined as the lack of administration in casualties who had received a blood transfusion with one or more of red blood cells, low-titre whole blood or French lyophilised plasma within the first 24 hours of injury and overuse as its administration in the non-transfused casualty.

RESULTS

Of the 76 patients included, 75 were men with an average age of 28 years. Five patients died during their management. 19 patients received TXA (25%) and 16 patients were transfused (21%). Underuse of TXA occurred in 3 of the 16 patients (18.8%) transfused. Overuse occurred in 6 of 60 (10%) non-transfused patients.

CONCLUSION

The analysis found an important underuse of TXA (almost 20%) and highlighted the need for optimising the prehospital clinical practice guidelines to aid prehospital medical practitioners more accurately in administering TXA to casualties that will require blood products.

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.

Hypothermia in the Combat Trauma Population

BACKGROUND

The MARCH (Massive hemorrhage, Airway, Respirations, Circulation, and Hypothermia/Head injuries) algorithm taught to military medics includes interventions to prevent hypothermia. As possible sequelae from major trauma, hypothermia is associated with coagulopathy and lower survival. This paper sought to define hypothermia within our combat trauma population using an outcomes-based method, and determine clinical variables associated with hypothermia.

METHODS

This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry focused on casualties who received prehospital care. A receiver operating curve was constructed and Youden's index was used to define hypothermia within the predetermined population based on mortality risk. A multivariable regression model was used to identify associations.

RESULTS

There were 23,243 encounters that met the inclusion criteria for this study with patients having received prehospital care and documentation of at least one emergency department temperature. An optimal threshold of 36.2° C was found to predict mortality; 3,159 casualties had temperatures below this threshold (14%). Survival to discharge was lower among casualties with hypothermia (91% versus 98%). Hypothermic casualties were less likely to undergo blanket application (38% versus 40%). However, they had higher proportions with Hypothermia Prevention and Management Kit application (11% versus 7%) and radiant warming (2% versus 1%). On multivariable regression modeling, none of the hypothermia interventions were associated with a decreased likelihood of hypothermia. Non-hypothermia interventions associated with hypothermia included prehospital intubation (OR 1.57, 95% CI 1.45-1.69) and blood product administration.

CONCLUSIONS

Hypothermia, including a single recorded low temperature in the patient care record, was associated with worse outcomes in this combat trauma population. Prehospital intubation was most strongly associated with developing hypothermia. Prehospital warming interventions were not associated with a reduction in hypothermia risk. Our dataset suggests that current methods for prehospital warming are inadequate.

Navy En-Route Care in future Distributed Maritime Operations: A review of clinician capabilities and roles of care

OBJECTIVE

As the United States Navy transitions from Operation Iraqi Freedom/Operation Enduring Freedom to preparing for a near-peer competition, an increasing focus of wartime strategy relies upon a network of distributed naval assets for total sea control, known as Distributed Maritime Operations (DMO). Historically, embedded medical personnel have provided care at sea in times of war. Recent reviews of shipboard and evacuated mass casualty incidents have alluded to weaknesses in the existing Navy Medicine approach that will require advances in care provision to sustain high-quality care that would benefit from industry and civilian academic collaboration. To gain input from civilian prehospital expertise and insight, the current DMO and Navy En-Route Care (ERC) systems must be plainly described for non-Navy military and civilian leaders, clinicians, and researchers to understand (1).

METHODS

N/AResults: In this review, we translate US Navy structure and vernacular into common civilian and non-Navy language, describe the maritime role-tiered ERC system, elucidate the medical assets on each naval warship, and discuss clinician levels and capabilities while deployed to help communicate the inherent challenges of US Navy maritime medical care during routine operations, casualty treatment, stabilization, and evacuation.

CONCLUSIONS

We describe the roles of care, clinician levels, and medical assets within the Navy ERC system for researchers and military leaders who aim to mitigate the inherent challenges of future maritime trauma care in the age of Distributed Maritime Operations. This paper lays the framework for the Navy deployed medical system to enable research in maritime en-route care, and prompt inclusion of identified solutions into common use in the US Navy.