An analysis of casualties presenting to military emergency departments in Iraq and Afghanistan

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 employment of resuscitative endovascular balloon occlusion of the aorta in deployed settings

BACKGROUND

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been often used in place of open aortic occlusion for management of hemorrhagic shock in trauma. There is a paucity of data evaluating REBOA usage in military settings.

STUDY DESIGN AND METHODS

We queried the Department of Defense Trauma Registry (DODTR) for all cases with at least one intervention or assessment available within the first 72 h after injury between 2007 and 2023. We used relevant procedural codes to identify the use of REBOA within the DODTR, and we used descriptive statistics to characterize its use.

RESULTS

We identified 17 cases of REBOA placed in combat settings from 2017 to 2019. The majority of these were placed in the operating room (76%) and in civilian patients (70%). A penetrating mechanism caused the injury in 94% of cases with predominantly the abdomen and extremities having serious injuries. All patients subsequently underwent an exploratory laparotomy after REBOA placement, with moderate numbers of patients having spleen, liver, and small bowel injuries. The majority (82%) of included patients survived to hospital discharge.

DISCUSSION

We describe 17 cases of REBOA within the DODTR from 2007 to 2023, adding to the limited documentation of patients undergoing REBOA in military settings. We identified patterns of injury in line with previous studies of patients undergoing REBOA in military settings. In this small sample of military casualties, we observed a high survival rate.

Interventions associated with survival after prehospital intubation in the deployed combat setting

INTRODUCTION

Airway compromise is the second leading cause of potentially preventable death on the battlefield. Prehospital airway management is often unavoidable in a kinetic combat environment and expected to increase in future wars where timely evacuation will be unreliable and air superiority not guaranteed. We compared characteristics of survivors to non-survivors among combat casualties undergoing prehospital airway intubation.

MATERIALS AND METHODS

We requested all Department of Defense Trauma Registry (DODTR) encounters during 2007-2023 with documentation of any airway intervention or assessment within the first 72-h after injury. We conducted a retrospective cohort study of all casualties with intubation documented in the prehospital setting. We used descriptive and inferential statistical analysis to compare survivors through 7 days post injury versus non-survivors. We constructed 3 multivariable logistic regression models to test for associations between interventions and 7-day survival after adjusting for injury severity score, mechanism of injury, and receipt of sedatives, paralytics, and blood products.

RESULTS

There were 1377 of 48,301 patients with documentation of prehospital intubation in a combat setting. Of these, 1028 (75%) survived through 7 days post injury. Higher proportions of survivors received ketamine, paralytic agents, parenteral opioids, and parenteral benzodiazepines; there was no difference in the proportions of survivors versus non-survivors receiving etomidate. The multivariable models consistently demonstrated positive associations between 7-day survival and receipt of non-depolarizing paralytics and opioid analgesics.

CONCLUSIONS

We found an association between non-depolarizing paralytic and opioid receipt with 7-day survival among patients undergoing prehospital intubation. The literature would benefit from future multi-center randomized controlled trials to establish optimal pharmacologic strategies for trauma patients undergoing prehospital intubation.

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.

Associations with Prehospital Antibiotic Receipt among Combat Casualties with Open Wounds: A Department of Defense Trauma Registry Study

INTRODUCTION

Current Tactical Combat Casualty Care (TCCC) guidelines recommend antibiotic administration for all open wounds to prevent infection. We identified associations between demographics, procedures, and medicines with the receipt of prehospital antibiotics among combat casualties.

MATERIALS AND METHODS

We used a series of emergency department procedure codes to identify adult subjects within the Department of Defense Trauma Registry from January 2007 to August 2016 who sustained open wounds. We compared demographics, procedures, and medicines administered among casualties receiving prehospital wound prophylaxis versus casualties not receiving antibiotic prophylaxis. We controlled for confounders with multivariable logistical regression.

RESULTS

We identified 18,366 encounters meeting inclusion criteria. Antibiotic recipients (n = 2384) were comparable to nonrecipients (n = 15,982) with regard to age and sex. Antibiotic recipients were more likely to sustain injuries from firearms and undergo all procedures examined related to hemorrhage control, airway management, pneumothorax treatment, and volume replacement except for intraosseous access. Antibiotic recipients were less likely to sustain injuries from explosives. Antibiotic recipients had a modestly higher survival than nonrecipients (97.4% versus 96.0%). Associations with prehospital antibiotic receipt in multivariable logistic regression included non-North Atlantic Treaty Organization military force affiliation (odds ratio (OR) 4.65, 95% CI, 1.0-20.8), tachycardia (OR 3.4, 95% CI, 1.1-10.5), intubation (OR 2.0, 95% CI, 1.1-3.8), and administration of tranexamic acid (OR 5.6, 95% CI, 1.2-26.5).

CONCLUSIONS

The proportion of combat casualties with open wounds receiving prehospital antibiotics was low despite published recommendations for early antibiotics in patients with open wounds. These findings highlight the ongoing need for additional educational and quality assurance initiatives to continue improving adherence to TCCC guidelines with regard to prehospital antibiotic administration. Future studies are necessary to determine reasons for suboptimal TCCC guideline compliance.

An Assessment of Clinical Accuracy of Vital Sign-based Triage Tools Among U.S. and Coalition Forces

INTRODUCTION

Early appropriate allocation of resources for critically injured combat casualties is essential. This is especially important when inundated with an overwhelming number of casualties where limited resources must be efficiently allocated, such as during mass casualty events. There are multiple scoring systems utilized in the prehospital combat setting, including the shock index (SI), modified shock index (MSI), simple triage and rapid treatment (START), revised trauma score (RTS), new trauma score (NTS), Glasgow Coma Scale + age + pressure (GAP), and the mechanism + GAP (MGAP) score. The optimal score for application to the combat trauma population remains unclear.

MATERIALS AND METHODS

This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry from January 1, 2007 through March 17, 2020. We constructed univariable analyses to determine the area under the receiving operator characteristic (AUROC) for the scoring systems of interest. Our primary outcomes were early death (within 24 hours) or early massive transfusion, as defined by ≥3 units.

RESULTS

There were 12,268 casualties that met inclusion criteria. There were 168 (1%) who died within the first 24 hours and 2082 (17%) that underwent significant transfusion within the first 24 hours. When assessing the predictive capabilities for death within 24 hours, the AUROCs were 0.72 (SI), 0.69 (MSI), 0.89 (START), 0.90 (RTS), 0.83 (NTS), 0.90 (GAP), and 0.91 (MGAP). The AUROCs for massive transfusion were 0.89 (SI), 0.89 (MSI), 0.82 (START), 0.81 (RTS), 0.83 (NTS), 0.85 (MGAP), and 0.86 (GAP).

CONCLUSIONS

This study retrospectively applied seven triage tools to a database of 12,268 cases from the Department of Defense Trauma Registry to evaluate their performance in predicting early death or massive transfusion in combat. All scoring systems performed well with an AUROC >0.8 for both outcomes. Although the SI and MSI performed best for predicting massive transfusion (both had an AUROC of 0.89), they ranked last for assessment of mortality within 24 hours, with the other tools performing well. START, RTS, NTS, MGAP and GAP reliably identified early death and need for massive transfusion, with MGAP and GAP performing the best overall. These findings highlight the importance of assessing triage tools to best manage resources and ultimately preserve lives of traumatically wounded warfighters. Further studies are needed to explain the surprising performance discrepancy of the SI and MSI in predicting early death and massive transfusion.

Seasonal Association With Hypothermia in Combat Trauma

INTRODUCTION

Hypothermia increases mortality in trauma populations and frequently occurs in military casualties due to the nature of combat environments. The association between hypothermia and the time of year when injured remains unclear. We sought to determine the association between seasonal changes in temperature and hypothermia among combat casualties.

MATERIALS AND METHODS

This observational study was a secondary analysis of a previously described Department of Defense Trauma Registry dataset which included U.S. military and Coalition casualties who received prehospital care from January 2007 to March 2020 in Afghanistan and Iraq. We tested for associations between hypothermia (<36.2°C) and seasonal ambient temperatures by constructing multivariable logistic regression models. Summer was defined as June through August and winter as December through February. We assumed that the combat operations occurred in the area near the point of first contact with the deployed military treatment facilities. This study was determined to be exempt from Institutional Review Board oversight.

RESULTS

There were 5,821 that met inclusion for this study. Within the multivariable logistic regression model, we adjusted for injury severity score, mechanism of injury, and imputed transport time, finding that combat casualties were 2.28 (odds ratio, 95% confidence interval 1.93-2.69) times more likely to develop hypothermia in the winter versus summer. When using temperature as a continuous outcome, casualties had a lower emergency department temperature during the winter (parameter estimate -0.133°C, P < 0.001) after adjusting for confounders. In casualties experiencing hypothermia, mortality was higher (4% versus 1%, P < 0.001), and composite median injury severity score values were higher (10 versus 5, P < 0.001). Among hypothermic casualties, serious injuries were significantly more common (all P < 0.001) to the head (15% versus 7%), thorax (15% versus 7%), abdomen (9% versus 6%), extremities (35% versus 22%), and skin (4% versus 2%).

CONCLUSIONS

We found a seasonal variation in the occurrence of hypothermia in a large cohort of trauma casualties. Despite adjustment for multiple known confounders, our findings substantiate probable ambient temperature variations to trauma-induced hypothermia. Furthermore, our findings, when taken in the context of other studies on the efficacy of current hypothermia prevention and treatment strategies, support the need for better methods to mitigate hypothermia in future cold-weather operations.

Association of Prehospital Neck Wound Survivability and Battlefield Medical Evacuation Time in Afghanistan

INTRODUCTION

The U.S. Military's Golden Hour policy led to improved warfighter survivability during the Global War on Terror. The policy's success is well-documented, but a categorical evaluation and stratification of medical evacuation (MEDEVAC) times based on combat injury is lacking.

METHODS

We queried the Department of Defense Joint Trauma System Prehospital Trauma Registry for casualties with documented penetrating neck trauma in Afghanistan requiring battlefield MEDEVAC from June 15, 2009, through February 1, 2021. Casualties were excluded if the time from the point of injury to reach higher level medical care was not documented, listed as zero, or exceeded 4 hours. They were also excluded if demographic data were incomplete or deemed unreliable or if their injuries occurred outside of Afghanistan.We designed a logistic regression model to test for associations in survivability, adjusting for composite injury severity score, patient age group, and type of next higher level of care reached. We then used our model to interpolate MEDEVAC times associated with 0.1%, 1%, and 10% increased risk of death for an incapacitated casualty with penetrating neck trauma.

RESULTS

Of 1,147 encounters, 444 casualties met inclusion criteria. Of these casualties, 430 (96.9%) survived to discharge. Interpolative analysis of our multivariable logistic regression model showed that MEDEVAC times ≥8 minutes, ≥53 minutes, and ≥196 minutes are associated with a 0.1%, 1%, and 10% increased risk of mortality from baseline, respectively.

CONCLUSIONS

Our data characterize the maximum MEDEVAC times associated with 0.1%, 1%, and 10% increased risk of death from baseline survivability for penetrating battlefield neck trauma in Afghanistan.

Exploring the competencies of operating room nurses in mobile surgical teams based on the Onion Model: a qualitative study

BACKGROUND

With the frequent occurrence of public health emergencies, conflicts and natural disasters around the world, mobile surgical teams are becoming more crucial. The competency of the operating room (OR) nurse has a substantial impact on the effectiveness and quality of the surgical team's treatment, still there is limited knowledge about OR nurse competencies in mobile surgical teams. This study aimed to explore the competencies of OR nurses in mobile surgical teams based on the Onion Model.

METHODS

We conducted a qualitative descriptive study of participants from 10 mobile surgical teams in 2022. Twenty-one surgical team members were interviewed, including 15 OR nurses, four surgeons, and two anesthesiologists. Data were collected through semi-structured interviews. The data were analyzed using Mayring's content analysis.

RESULTS

Twenty-eight competencies were found in the data analysis, which were grouped into four major domains using the Onion Model. From the outer layer to the inner layer were knowledge and skills, professional abilities, professional quality, and personal traits. The qualitative data revealed several novel competencies, including triage knowledge, self and mutual medical aid, outdoor survival skills, and sense of discipline.

CONCLUSIONS

The application of the Onion Model promotes the understanding of competency and strengthens the theoretical foundations of this study. New competencies can enrich the content of the competencies of OR nurses. The results of this study can be used for clinical recruitment, evaluation and training of OR nurses in mobile surgical teams. This study encourages further research to develop competency assessment tools and training programs for OR nurses.

Local Effect of Ballistic Fragments Embedded Along the Carotid Sheath of a Porcine Animal Model

INTRODUCTION

Energized ballistic fragments from improvised explosive devices were the most common cause of injury to coalition service personnel during conflicts in Iraq and Afghanistan. Surgical excision of retained fragments is not routinely performed unless there is a concern for injury to vital structures. However, no clear guidelines dictate when or if a fragment should be removed, reflecting a lack of objective evidence of their long-term effects. Using a porcine model, we aimed to evaluate changes to the carotid artery produced by retained fragments over time.

MATERIALS AND METHODS

Institutional Animal Care and Use Committee approval for all experiments was obtained before commencement of the study. Eighteen female swine (mean mass 62.0 ± 3.4 kg) were randomized into three study groups corresponding to the time of survival after implantation of ballistic fragments: 1, 6, and 12 weeks. Two animals from each group were randomly assigned to have one of the three different fragments implanted within the right carotid sheath in zones 1-3 of the neck. The left carotid served as the control. The vascular flow rate and arterial diameter were measured at each level before implantation and again after the survival interval. Baseline and interval angiograms were performed to identify gross vascular changes.

RESULTS

No abnormalities were identified on baseline or interval angiograms. No significant difference was found when the baseline was compared to interval measurements or when compared to the control side for all gross and physiological measures at 1 and 6 weeks (P = .053-.855). After 12 weeks, the flow and diameter changed significantly (P < .001-.03), but this significant change was found in both the control and affected carotid.

CONCLUSIONS

The lack of significant gross anatomical and physiological changes at 6 weeks postimplantation lends evidence toward the current policy that early removal of retained ballistic fragments around cervical vessels is not required. Changes were significant after 12 weeks which suggest that surveillance may be required; however, such changes could be explained by physiological animal growth.

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.

A Retrospective Analysis of Combat Injury Patterns and Prehospital Interventions Associated with the Development of Sepsis

BACKGROUND

Combat injury related wound infections are common. Untreated, these wound infections may progress to sepsis and septic shock leading to increased morbidity and mortality rates. Understanding infectious complications, patterns, progression, and correlated prehospital interventions are vital to understand the development of sepsis. We aim to analyze demographics, injury patterns, and interventions associated with sepsis in battlefield settings.

MATERIALS AND METHODS

This is a secondary analysis of previously published data from the Department of Defense Trauma Registry (DoDTR) from 2007 to 2020. We searched for casualties diagnosed with sepsis (excluding line-sepsis) throughout their initial hospitalization. Regression models were used to seek associations.

RESULTS

Our initial request yielded 28,950 encounters, of which 25,654 (88.6%) were adults that met inclusion, including 243 patients (0.9%) diagnosed with sepsis. Patients included US military (34%), non-North Atlantic Treaty Organization (NATO) military (33%) and humanitarian (30%) groups. Patients diagnosed with sepsis had a significantly lower survival rate than non-septic patients (78.1% vs. 95.7%, p < 0.001). There was no significant difference in administration of prehospital antibiotics between septic and the general populations (10.6% vs. 12.3%, p = 0.395). Prehospital intraosseous access (OR 1.56, 95% CI 1.27-1.91, p = 0.207) and packed red cell administration (1.63, 1.24-2.15, 0.029) were the interventions most associated with sepsis.

CONCLUSIONS

Sepsis occurred infrequently in the DoDTR when evacuation from battlefield is not delayed, but despite increased intervention frequency, developing sepsis demonstrates a significant drop in survival rates. Future research would benefit from the development of risk mitigation measures.

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

As the wars in Iraq and Afghanistan end, the US military has begun to transition to the multi-domain operations concept with preparation for large scale combat operations against a near-peer adversary. In large scale combat operations, the deployed trauma system will likely see challenges not experienced during the Global War on Terrorism. The development of science and technology will be critical to close existing capability gaps and optimize casualty survival. This review comprises a framework of deployed trauma care to provide nonmilitary investigators a general understanding of our deployed trauma care system. Trauma care begins at the Role 1 which encompasses all care from the point of injury and the battalion aid station, through transport to the Role 2 or forward staged mobile surgical team such as a Forward Resuscitative Surgical Detachment. Role 1 point of injury care approximates the care delivered by Emergency Medical Services (EMS) personnel. The Battalion Aid Station approximates the care available at a freestanding emergency center with significant differences in training level of the providers, number of beds, and diagnostic capabilities. Role 2 medical care is part of an area support medical company with surgical capabilities. The Role 2 represents the first role of care which provides damage control surgery. This capability approximates a small community hospital with the primary difference being limited patient holding capacity and reduced diagnostic equipment. The Role 3 field hospital is the largest military treatment facility in the deployed setting. The Role 3 approximates a civilian level 2 trauma center with smaller holding capabilities and diagnostic abilities limited to that of a computed tomography (CT) scanner and less.

The effectiveness of simulation-based training on the competency of military nurses: A systematic review

BACKGROUND

Simulation is an integral component of healthcare education and military training. There is substantial evidence demonstrating the effectiveness of simulation-based training in nursing and the military; however, its effectiveness for military nurses has not been established in systematic reviews.

OBJECTIVE

To evaluate the effectiveness of simulation-based training on the competency of military nurses and provide guidance for future research on the training of military nurses.

DESIGN

A scoping literature review of PRISMA was used to guide the review.

METHODS

Six databases (PubMed, CINAHL, EMBASE, PsycINFO, Embase, and the Cochrane Library) were searched for English articles. The following search terms were used in different combinations: simulation, simulate, military, army, nurses, competency, training, and education. Our database search began in 2000 and ended in February 2022. Additionally, we conducted a manual search of the references of the identified studies.

RESULTS

In this review, ten studies published between 2008 and 2021 were included, nine were from the United States and one was from the United Kingdom. The results showed that simulation-based interventions were effective in military nurse competency training, including individual knowledge, skills, abilities and thinking, team communication and collaboration abilities, competency enhancement and maintenance. Simulations can effectively train the competencies of newly graduated military nurses, nurses during daily work, and in preparing nurses during deployment.

CONCLUSION

Existing studies on simulation-based training of military nurses are limited. Additional research is needed to assess other competency training for military nurses, pre-deployment training, and training using other simulation methods. It is important to find suitable simulation training methods for the different competencies required of military nurses.

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.

An analysis of early volume resuscitation and the association with prolonged mechanical ventilation

BACKGROUND

Previous studies have found that intravenous fluid administration within the first 24 h may be associated with prolonged mechanical ventilation (PMV). We examined the association between initial 24 h fluids and PMV in combat casualties.

METHODS

This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry (DODTR). We included casualties with at least 24 h on the ventilator and no significant traumatic brain injury. The definition of PMV and associations were constructed using univariable and multivariable logistic regression models.

RESULTS

We identified 1508 casualties available for analysis for this study - 1275 in the non-PMV cohort (<9 days on ventilator vs. 233 in the PMV cohort (≥9 days on ventilator). Explosives comprised the most common mechanism of injury for both groups (72% vs. 75%) followed by firearms (21% vs. 16%). The composite injury severity score (ISS) was lower in the non-PMV cohort (18 vs. 30, p < .001). There were lower volumes of all resuscitation fluid within the first 24 h in the non-PMV cohort. When adjusting for composite ISS and mechanism of injury in a multivariable logistic regression model with PMV as the outcome, crystalloid volume (unit odds ratio [UOR] 1.07) and colloid volume (UOR 1.03) were both associated with PMV.

CONCLUSIONS

We found that volume of resuscitation fluids were substantially higher in the PMV cohort. Our findings suggest the need for caution with the routine use of crystalloid and colloid in the first 24 h of resuscitation.

Injury mechanisms and injury severity scores as determinants of urban terrorism-related thoracoabdominal injuries

Objective: Improving the care of injuries resulting from terrorist attacks requires understanding injury mechanisms in armed conflicts. The aim of this study was to identify injury characteristics in military personnel with thoracoabdominal combat injuries resulting from terrorist attacks in urban settings.

Material and Methods: A retrospective study of military personnel with thoracoabdominal injuries who were referred to a tertiary center after treating and stabilizing at a primary healthcare organization due to terror-related injuries in various urban regions of Turkey between June 2015 and December 2016 was performed.

Results: A total of 70 patients were included in this study, of whom 87.1% were injured by explosives and 12.9% (n= 9) had gunshot wounds (GSWs). Mean injury severity score (ISS) was 21, blood transfusion amount was 3.7 units, and mortality rate was 8.5%. Patients injured by explosives had most commonly abdominal and extremity injuries (31.1%), whereas isolated abdominal injuries (55.6%) were observed among patients with GSWs. There were no significant differences between the mechanisms of injuries and the ISS, blood transfusion, and mortality (p= 0.635, p= 0.634, and p= 0.770, respectively). A significant correlation was observed between the ISS and transfusion amounts (r= 0.548, p< 0.001). Mortality was significantly higher in those with a high ISS and those undergoing massive blood transfusions (p= 0.004 and p< 0.001, respectively).

Conclusion: Explosive injuries, concomitant vascular injuries, high ISS, and the need for massive transfusions increased the mortality rate in urban combat injuries. To quickly identify high-risk patients and improve the care of injuries, it is essential to use predictive models or scoring systems.

An Analysis of Ketamine Doses Administrated to Nonintubated Casualties Prehospital

INTRODUCTION

Previous studies demonstrate that a significant proportion of casualties do not receive pain medication prehospital after traumatic injuries. To address possible reasons, the U.S. Military has sought to develop novel delivery methods to aid in administration of pain medications prehospital. We sought to describe the dose and route of ketamine administered prehospital to help inform materiel solutions.

MATERIALS AND METHODS

This is a secondary analysis of a previously described dataset focused on prehospital data within the Department of Defense Trauma Registry from 2007 to 2020. We isolated encounters in which ketamine was administered along with the amount dosed and the route of administration in nonintubated patients.

RESULTS

Within our dataset, 862 casualties met inclusion for this analysis. The median age was 28 and nearly all (98%) were male. Most were battle injuries (88%) caused by explosives (54%). The median injury severity score was 10 with the extremities accounting to the most frequent seriously injured body region (38%). The mean dose via intravenous route was 50.4 mg (n = 743, 95% CI 46.5-54.3), intramuscular was 66.7 mg (n = 234, 95% CI 60.3-73.1), intranasal was 56.5 mg (n = 10, 39.1-73.8), and intraosseous was 83.3 mg (n = 34, 66.3-100.4). Most had a medic or CLS in their chain of care (87%) with air evacuation as the primary mechanism of evacuation (86%).

CONCLUSIONS

The average doses administered were generally larger than the doses recommended by Tactical Combat Casualty Care guidelines. Currently, guidelines may underdose analgesia. Our data will help inform materiel solutions based on end-user requirements.

A Descriptive Analysis of Supermassive Transfusion Recipients Among US and Coalition Forces During Combat Operations in Afghanistan and Iraq

INTRODUCTION

Hemorrhage is the leading cause of potentially preventable death on the battlefield. Resuscitation with blood products is essential to restore circulating volume, repay the oxygen debt, and prevent coagulopathy. Massive transfusion (MT) occurs frequently after major trauma; a subset of casualties requires a supermassive transfusion (SMT), and thus, mobilization of additional resources remains unclear.

MATERIALS AND METHODS

This is a secondary analysis of a previously described dataset from the Department of Defense Trauma Registry. In this analysis, we isolated U.S. and Coalition casualties that received at least 1 unit of packed red blood cells (PRBCs) or whole blood (WB). Given a lack of consensus on the definition of SMT recipients, we included those patients receiving the top quartile of PRBC and WB administered within the first 24 hours following arrival to a military treatment facility.

RESULTS

We identified 25,897 adult casualties from January 1, 2007 to March 17, 2020. Within this dataset, 2,608 (9.0%) met inclusion for this analysis. The median number of total products administered within the first 24 hours was 8 units of PRBC or WB. The upper quartile was 18 units (n = 666). Compared to all other blood product recipients, patients in the SMT cohort had a higher median injury severity score (27 vs 18, P < 0.001), were most frequently injured by explosives (84.9% vs 68.6%, P < 0.001), had a higher mean emergency department (ED) pulse (128 vs 111, P < 0.001), a lower mean systolic blood pressure (122 vs 132 mm Hg, P < 0.001), and a higher mean international normalized ratio (1.68 vs 1.38, P < 0.001). SMT patients experienced lower survival to hospital discharge (85.8% vs 93.3%, P < 0.001).

CONCLUSIONS

Compared to all other PRBC and WB recipients, SMT patients experienced more injury by explosives, severe injury patterns, ED vital sign derangements, and mortality. These findings may help identify those casualties who may require earlier aggressive resuscitation. However, more data is needed to define this population early in their clinical course for early identification to facilitate rapid resource mobilization. Identifying casualties who are likely to die within 24 hours compared to those who are likely to survive, may assist in determining a threshold for a SMT.

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.

Efficacy of the compensatory reserve measurement in an emergency department trauma population

BACKGROUND

The Compensatory Reserve Measurement (CRM) is a novel method used to provide early assessment of shock based on arterial wave form morphology changes. We hypothesized that (1) CRM would be significantly lower in those trauma patients who received life-saving interventions compared with those not receiving interventions, and (2) CRM in patients who received interventions would recover after the intervention was performed.

STUDY DESIGN AND METHODS

We captured vital signs along with analog arterial waveform data from trauma patients meeting major activation criteria using a prospective study design. Study team members tracked interventions throughout their emergency department stay.

RESULTS

Ninety subjects met inclusion with 13 receiving a blood product and 10 a major airway intervention. Most trauma was blunt (69%) with motor vehicle collisions making up the largest proportion (37%) of injury mechanism. Patients receiving blood products had lower CRM values just prior to administration versus those who did not (50% versus 58%, p = .045), and lower systolic pressure (SBP; 95 versus 123 mmHg, p = .005), diastolic (DBP; 62 versus 79, p = .007), and mean arterial pressure (MAP; 75 versus 95, p = .006), and a higher pulse rate (HR; 101 versus 89 bpm, p = .039). Patients receiving an airway intervention had lower CRM values just prior to administration versus those who did not (48% versus 58%, p = .062); however, SBP, DBP, MAP, and HR were not statistically distinguishable (p ≥ .645).

CONCLUSIONS

Our results support our hypotheses that the CRM distinguished those patients who received blood or an airway intervention from those who did not, and increased appropriately after interventions were performed.

An Analysis of Intracranial Hemorrhage in Wartime Pediatric Casualties

BACKGROUND

Children make up a significant cohort of patients treated at combat support hospitals. Where traumatic head injury, including intracranial hemorrhage (ICH), is well studied in military adults, such research is lacking regarding pediatric patients. We seek to describe the incidence and outcomes of ICH within this population.

METHODS

This is a secondary analysis of a previously published dataset from the Department of Defense Trauma Registry for all pediatric casualties in Iraq and Afghanistan from January 2007 to January 2016. Within our dataset, we searched for casualties with an ICH.

RESULTS

Of the 3439 pediatric encounters in our dataset, we identified 495 (14%) casualties that had at least 1 type of ICH. Most were between 5 and 12 years of age, male (74%), and injured by an explosive (42%). Of the casualties with ICHs, 82 had epidural (16.6%), 237 had subdural (47.9%), 153 had subarachnoid (30.9%), 157 had parenchymal bleeds (31.7%), and 239 had ICHs not otherwise specified (48.3%). In the hospital setting, the epidural group was more frequently treated with skull decompression (41%) and craniotomy with skull elevation (28%). The subdural group was more frequently treated with a craniectomy (17%) and the parenchymal group had more frequent intracranial pressure monitoring (18%). In our dataset, 22 received ketamine prehospital (4.4%) and most were discharged alive from the hospital (79%).

CONCLUSIONS

Within our dataset, we identified 495 cases of ICH in pediatric patients. Most survived to hospital discharge despite less than half undergoing a decompression procedure.

An Analysis of Airway Interventions in the Setting of Smoke Inhalation Injury on the Battlefield

INTRODUCTION

The Committee on Tactical Combat Casualty Care and Capabilities Development and Integration Directorate cite airway burn injuries as an indication for prehospital cricothyrotomy. We sought to build on previously published data by describing for the first time the incidence of prehospital airway interventions in combat casualties who received airway management in the setting of inhalational injuries.15,26 We hypothesized that (1) airway interventions in combat casualties who suffered inhalational injury would have a higher mortality rate than those without airway intervention and (2) prehospital cricothyrotomy was used with greater incidence than endotracheal intubation.

MATERIALS AND METHODS

Using a previously described Department of Defense Trauma Registry dataset from January 2007 to August 2016, unique casualties with documented inhalational injury were identified.

RESULTS

Our predefined search codes captured 28,222 (72.8% of all encounters in the registry) of those subjects. A total of 347 (1.2%) casualties had a documented inhalational injury, 27 (7.8%) of those with at least 1 prehospital airway intervention inhalational injuries (0.09% of our dataset [n = 28,222]). Within the subset of patients with an inhalation injury, 23 underwent intubation, 2 underwent cricothyrotomy, 3 had placement of an airway adjunct not otherwise specifically listed, and 1 casualty had both a cricothyrotomy and intubation documented. No casualties had a supraglottic, nasopharyngeal, or oropharyngeal airway listed. Contrary to our hypotheses, of those with an airway intervention, 74.0% survived to hospital discharge. In multivariable regression models, when adjusting for confounders, there was no difference in survival to discharge in those with an airway intervention compared to those without.

CONCLUSIONS

Casualties undergoing airway intervention for inhalation injuries had similar survival adjusting for injury severity, supporting its role when indicated. Without case-specific data on airway status and interventions, it is challenging to determine if the low rate of cricothyrotomy in this population was a result of rapid transport to a more advanced provider capable of performing intubation or cricothyrotomy may not be meeting the needs of the medics.

An Analysis of 13 Years of Prehospital Combat Casualty Care: Implications for Maintaining a Ready Medical Force

Background: Most potentially preventable deaths occur in the prehospital setting before reaching a military treatment facility with surgical capabilities. Thus, optimizing the care we deliver in the prehospital combat setting represents a ripe target for reducing mortality. We sought to analyze prehospital data within the Department of Defense Trauma Registry (DODTR). Materials and methods: We requested all encounters with any prehospital activity (e.g., interventions, transportation, vital signs) documented within the DODTR from January 2007 to March 2020 along with all hospital-based data that was available. We excluded from our search casualties that had no prehospital activity documented. Results: There were 28,950 encounters that met inclusion criteria. Of these, 25,897 (89.5%) were adults and 3053 were children (10.5%). There was a steady decline in the number of casualties encountered with the most notable decline occurring in 2014. U.S. military casualties comprised the largest proportion (n = 10,182) of subjects followed by host nation civilians (n = 9637). The median age was 24 years (interquartile range/IQR 21-29). Most were battle injuries (78.6%) and part of Operation ENDURING FREEDOM (61.8%) and Operation IRAQI FREEDOM (24.4%). Most sustained injuries from explosives (52.1%) followed by firearms (28.1%), with serious injury to the extremities (24.9%) occurring most frequently. The median injury severity score was 9 (IQR 4-16) with most surviving to discharge (95.0%). A minority had a documented medic or combat lifesaver (27.9%) in their chain of care, nor did they pass through an aid station (3.0%). Air evacuation predominated (77.9%). Conclusions: Within our dataset, the deployed U.S. military medical system provided prehospital medical care to at least 28,950 combat casualties consisting mostly of U.S. military personnel and host nation civilian care. There was a rapid decline in combat casualty volumes since 2014, however, on a per-encounter basis there was no apparent drop in procedural volume.

High crystalloid volumes negate benefit of hemostatic resuscitation in pediatric wartime trauma casualties

BACKGROUND

Recent data for adult trauma patients suggest improved survival when using hemostatic resuscitation, which includes limiting crystalloids and using closer to 1:1 ratios for both fresh frozen plasma (FFP) and platelets (PLTs) relative to packed red blood cells (PRBCs). Pediatric studies have shown similar but mixed results and often lack measuring crystalloids. We seek to evaluate in-hospital survival based on crystalloid administration and different blood product ratios in pediatric casualties during the recent conflicts.

METHODS

We queried the Department of Defense Trauma Registry for all pediatric encounters in Iraq and Afghanistan from January 2007 to January 2016 and included those with at least 40 mL/kg of total blood products administered provided that they received at least 1 U of PRBC. We grouped children as younger (0-7 years) and older (8-17 years). We grouped low versus high ratios for FFP/PRBC (≤1:2 vs. >1:2) and PLT/PRBC (≤1:6 vs. >1.6). We used a threshold of 40 mL/kg to for high versus low crystalloid resuscitation.

RESULTS

During this time, there were 3,439 encounters in the registry with 521 (15.1%) that met the inclusion criteria. The median age of casualties that met the inclusion was 10 years (interquartile range, 5-13), most were male (73.5%), with a moderate median injury severity score (17; interquartile range, 13-25). We performed regression modeling with adjustments for mechanism of injury, composite injury severity score, and total blood product volume (mL/kg based), grouping children based on high versus low fluid resuscitation. In the low-volume crystalloid group, we found that higher (>1:2) FFP/PRBC was associated with improved survival (odds ratio [OR], 3.42). However, in the high fluid crystalloid resuscitation group, we found that that higher ratios for PLT/PRBC (>1:6) overall (OR, 0.46) and the FFP/PRBC (>1:2) in younger children (OR, 0.28) was associated with worse survival. The remaining associations were not statistically significant.

CONCLUSION

We found an association with survival in massively transfused pediatric trauma patients who received both a high FFP/PRBC ratio and low crystalloid administration. The benefit of this high ratio is negated, in patients receiving high crystalloid volumes, particularly among smaller children. Future studies on hemostatic resuscitation evaluating blood product ratios should also account for crystalloid and colloid administration.

LEVEL OF EVIDENCE

Retrospective, comparative, level III.

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

INTRODUCTION

In the far forward combat environment, the use of whole blood is recommended for the treatment of hemorrhagic shock after injury. In 2016, US military special operations teams began receiving low titer group O whole blood (LTOWB) for use at the point of injury (POI). This is a case series of the initial 15 patients who received LTOWB on the battlefield.

METHODS

Patients were identified in the Department of Defense Trauma Registry, and charts were abstracted for age, sex, nationality, mechanism of injury, injuries and physiologic criteria that triggered the transfusion, treatments at the POI, blood products received at the POI and the damage-control procedures done by the first surgical team, next level of care, initial interventions by the second surgical team, Injury Severity Score, and 30-day survival. Descriptive statistics were used to characterize the clinical data when appropriate.

RESULTS

Of the 15 casualties, the mean age was 28, 50% were US military, and 63% were gunshot wounds. Thirteen patients survived to discharge, one died of wounds after arrival at the initial resuscitative surgical care, and two died prehospital. The mean Injury Severity Score was 21.31 (SD, 18.93). Eleven (68%) of the causalities received additional blood products during evacuation/role 2 and/or role 3. Vital signs were available for 10 patients from the prehospital setting and 9 patients upon arrival at the first surgical capable facility. The mean systolic blood pressure was 80.5 prehospital and 117 mm Hg (p = 0.0002) at the first surgical facility. The mean heart rate was 105 beats per minute prehospital and 87.4 beats per minute (p = 0.075) at the first surgical facility. The mean hospital stay was 24 days.

CONCLUSION

The use of cold-stored LTOWB at POI is feasible during combat operations. Further data are needed to validate and inform best practice for POI transfusion.

LEVEL OF EVIDENCE

Therapeutic study, level V.

An analysis of radial pulse strength to recorded blood pressure in the Department of Defense Trauma Registry

Introduction

Hemorrhage is the leading cause of potentially preventable death on the battlefield. The tactical combat casualty care guidelines recommend the use of the radial pulse strength to guide the administration of blood products or intravenous fluids when equipment for blood pressure monitoring is not available. Data supporting this measurement tool are limited. We sought to validate this method in a deployed trauma population.

Materials and Methods

This is a secondary analysis of a previously published dataset from the Department of Defense Trauma Registry. In this subanalysis, we focused on emergency department radial pulse strength documented in conjunction with systolic blood pressure readings.

Results

Our predefined search codes captured 28,222 Department of Defense Trauma Registry casualties. Of those, 22,192 casualties had at least 1 radial pulse strength documented, with a total of 27,366 documented measurements total among the 22,192. The median age of casualties was 25 years, most were male (96.8%), U.S. military made up the largest proportion (44.2%), most were injured by explosive (55.8%), and most were in Afghanistan (67.0%) with a median injury severity score of 9. Mean systolic blood pressures were significantly different based on radial pulse strength: strong (129.6), weak (107.5), and absent (85.1). However, when using a binary threshold of 80 mmHg, there were 615 documented instances of hypotension. Within that 615, 55.6% had a strong radial pulse, 29.3% had a weak radial pulse, and 15.1% had an absent radial pulse (P &lt; .001).

Conclusions

Although mean systolic blood pressure was associated with radial pulse quality, when using a binary measurement of hypotension (systolic &lt; 80 mmHg) characterization of the radial pulse was not a reliable indicator of hypotension. Better methods for casualty monitoring must be employed to avoid missing opportunities for intervention.

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.

Wearable Sensors Incorporating Compensatory Reserve Measurement for Advancing Physiological Monitoring in Critically Injured Trauma Patients

Vital signs historically served as the primary method to triage patients and resources for trauma and emergency care, but have failed to provide clinically-meaningful predictive information about patient clinical status. In this review, a framework is presented that focuses on potential wearable sensor technologies that can harness necessary electronic physiological signal integration with a current state-of-the-art predictive machine-learning algorithm that provides early clinical assessment of hypovolemia status to impact patient outcome. The ability to study the physiology of hemorrhage using a human model of progressive central hypovolemia led to the development of a novel machine-learning algorithm known as the compensatory reserve measurement (CRM). Greater sensitivity, specificity, and diagnostic accuracy to detect hemorrhage and onset of decompensated shock has been demonstrated by the CRM when compared to all standard vital signs and hemodynamic variables. The development of CRM revealed that continuous measurements of changes in arterial waveform features represented the most integrated signal of physiological compensation for conditions of reduced systemic oxygen delivery. In this review, detailed analysis of sensor technologies that include photoplethysmography, tonometry, ultrasound-based blood pressure, and cardiogenic vibration are identified as potential candidates for harnessing arterial waveform analog features required for real-time calculation of CRM. The integration of wearable sensors with the CRM algorithm provides a potentially powerful medical monitoring advancement to save civilian and military lives in emergency medical settings.

Level 1 Trauma Centers and OEF/OIF Emergency Departments: Comparison of Trauma Patient Populations

INTRODUCTION

Brooke Army Medical Center (BAMC), the largest military hospital and the only level 1 trauma center in the DoD, cares for active duty, retired uniformed services personnel, and beneficiaries. In addition, BAMC works in collaboration with the Southwest Texas Regional Advisory Council (STRAC) and University Hospital (UH), San Antonio's other level 1 trauma center, to provide trauma care to residents of the city and 22 counties in southwest Texas from San Antonio to Mexico (26,000 square mile area). Civilian-military partnerships are shown to benefit the training of military medical personnel; however, to date, there are no published reports specific to military personnel experiences within emergency care. The purpose of the current study was to describe and compare the emergency department trauma patient populations of two level 1 trauma centers in one metropolitan city (BAMC and UH) as well as determine if DoD level 1 trauma cases were representative of patients treated in OEF/OIF emergency department settings.

MATERIALS AND METHODS

We obtained a nonhuman subjects research determination for de-identified data from the US Air Force 59th Medical Wing and the University of Texas Health Science Center at San Antonio Institutional Review Boards. Data on emergency department patients treated between the years 2015 and 2017 were obtained from the two level 1 trauma centers (BAMC and UH, located in San Antonio, Texas); data included injury descriptors, ICU and hospital days, and department procedures.

RESULTS

Two-proportion Z-tests indicated that trauma patients were similar across trauma centers on injury type, injury severity, and discharge status; yet trauma patients differed significantly in terms of mechanism of injury and regions of injury. BAMC received significantly greater proportions of patients injured from falls, firearms and with facial and head injuries than UH, which received significantly greater proportion of patients with thorax and abdominal injuries. In addition, a significantly greater proportion of patients spent more than 2 days in the ICU and greater than two total hospital days at BAMC than in UH. In comparison to military emergency departments in combat zones, BAMC had significantly lower rates of blood product administration and endotracheal intubations.

CONCLUSIONS

The trauma patients treated at a military level 1 trauma center were similar to those treated in the civilian level 1 trauma center in the same city, indicating the effectiveness of the only DoD Level 1 trauma center to provide experience comparable to that provided in civilian trauma centers. However, further research is needed to determine if the exposure rates to specific procedures are adequate to meet predeployment readiness requirements.

Analysis of Prehospital Administration of Blood Products to Pediatric Casualties in Iraq and Afghanistan

BACKGROUND

Hemorrhage is one of the leading causes of preventable death in both military and civilian trauma. Implementation of items such as tourniquets and hemostatic dressings are helpful in controlling hemorrhage and increasing the survival rate of casualties when such injuries occur. Prehospital blood transfusions are used to treat patients with severe injuries where the standard methods of hemorrhage control are not an effective form of treatment. There is limited research and no widely accepted protocol on pediatric prehospital blood transfusions.

METHODS

We queried the Department of Defense Trauma Registry (DODTR) for all pediatric subjects admitted to U.S. and Coalition fixed-facility hospitals in Iraq and Afghanistan from January 2007 to January 2016. This is a secondary analysis of casualties that received blood products prehospital.

RESULTS

From January 2007 through January 2016 there were 3439 pediatric casualties within the registry. Within this group, 22 casualties that received one or more blood product prehospital were identified. Children in the 10-14 years age (40%) group made up the largest proportion, 86% were male, almost all were injured by explosive (63%) or firearm (27%), and 77% survived to hospital discharge. The most frequently administered blood product was packed red cells (n = 17). Of the 22, 15 underwent massive transfusion within the first 24 hours of admission.

CONCLUSIONS

Prehospital administration of blood products occurred infrequently within this pediatric dataset, but those that received blood were critically injured with most receiving a massive transfusion. Given the frequency with which medical personnel are carrying blood products in the prehospital, combat setting, guidelines specific to pediatric administration would be beneficial.

Ketamine Administration in Prehospital Combat Injured Patients With Traumatic Brain Injury: A 10-Year Report of Survival

Background

The Tactical Combat Casualty Care (TCCC) guidelines recommend ketamine as the primary battlefield analgesic in the setting of moderate-to-severe pain and hemodynamic compromise. However, despite recent studies failing to support the association between ketamine and worse outcomes in head trauma, TCCC guidelines state that ketamine may worsen severe traumatic brain injury. We compared mortality outcomes following head trauma sustained in a combat setting between ketamine recipients and non-recipients.

Methods

This is a secondary analysis of previously published data in the Department of Defense Trauma Registry from January 2007 to August 2016. We isolated patients with an abbreviated injury scale of 3 or greater for the head body region. We compared mortality between prehospital ketamine recipients and non-recipients.

Results

Our initial search yielded 28,222 patients, of which 4,183 met the inclusion criteria: 209 were ketamine-recipients and 3,974 were non-recipients. The ketamine group had a higher percentage injured by explosives (59.81% vs. 53.57%, p<0.001) and gunshot wounds (28.71% vs. 22.07%, p<0.001) and were more frequently located in Afghanistan (100% vs. 68.0%, p<0.001). The ketamine group had higher rates of tourniquet application (24.4% vs. 8.5%, p<0.001) and had lower survival proportion (75.1% alive vs. 83.0%, p=0.003). All differences were significant. On univariable analysis, the ketamine group had worse odds of survival with (OR: 0.62; 95%CI: 0.45-0.86). When controlling for the presence of an airway intervention and mechanism of injury, the finding was non-significant (OR: 1.09; 95% CI: 0.76-1.55).

Conclusions

In our prehospital combat study, after controlling for confounders, we found no association between administration of prehospital ketamine and worse survival outcomes for casualties with head injuries. However, despite the lack of difference in overall survival noted, those who received ketamine and died had a higher risk ratio for time to death.

Validation of the age-adjusted shock index for pediatric casualties in Iraq and Afghanistan

BACKGROUND

Pediatric casualties account for a notable proportion of encounters in the deployed setting based on the humanitarian medical care mission. Previously published data demonstrates that an age-adjust shock index may be a useful tool in predicting massive transfusion and death in children. We seek to determine if those previous findings are applicable to the deployed, combat trauma setting.

METHODS

We queried the Department of Defense Trauma Registry (DODTR) for all pediatric subjects admitted to US and Coalition fixed-facility hospitals in Iraq and Afghanistan from January 2007 to January 2016. This is a secondary analysis of casualties seeking to validate previously published data using the shock index, pediatric age-adjusted. We then used previously published thresholds to determine patients outcome for validation by age grouping, 1-3 years (1.2), 4-6 years (1.2), 7-12 years (1.0), 13-17 years (0.9).

RESULTS

From January 2007 through January 2016 there were 3439 pediatric casualties of which 3145 had a documented heart rate and systolic pressure. Of those 502 (16.0%) underwent massive transfusion and 226 (7.2%) died prior to hospital discharge. Receiver operating characteristic (ROC) thresholds were inconsistent across age groups ranging from 1.0 to 1.9 with generally limited area under the curve (AUC) values for both massive transfusion and death prediction characteristics. Using the previously defined thresholds for validation, we report sensitivity and specificity for the massive transfusion by age-group: 1-3 (0.73, 0.35), 4-6 (0.63, 0.60), 7-12 (0.80, 0.57), 13-17 (0.77, 0.62). For death, 1-3 (0.75, 0.34), 4-6 (0.66-0.59), 7-12 (0.64, 0.52), 13-17 (0.70, 0.57). However, negative predictive values (NPV) were generally high with all greater than 0.87.

CONCLUSIONS

Within the combat setting, the age-adjusted pediatric shock index had moderate sensitivity and relatively poor specificity for predicting massive transfusion and death. Better scoring systems are needed to predict resource needs prior to arrival, that perhaps include other physiologic metrics. We were unable to validate the previously published findings within the combat trauma population.

Development of prehospital assessment findings associated with massive transfusion

BACKGROUND

Massive transfusion is frequently a component of the resuscitation of combat casualties. Because blood supplies may be limited, activation of a walking blood bank and mobilization of necessary resources must occur in a timely fashion. The development of a risk prediction model to guide clinicians for early transfusion in the prehospital setting was sought.

STUDY DESIGN AND METHODS

This is a secondary analysis of a previously described data set from the Department of Defense Trauma Registry from January 2007 to August 2016 focusing on casualties undergoing massive transfusion. Serious injury was defined based on an Abbreviated Injury Scale score of 3 or greater by body region. The authors constructed multiple imputations of the model for risk prediction development. Efforts were made to internally validate the model.

RESULTS

Within the data set, there were 15540 patients, of which 1238 (7.9%) underwent massive transfusion. In the body region injury scale model, explosive injuries (odds ratio [OR], 3.78), serious extremity injuries (OR, 6.59), and tachycardia >120/min (OR, 5.61) were most strongly associated with receiving a massive transfusion. In the simplified model, major amputations (OR, 17.02), tourniquet application (OR, 6.66), and tachycardia >120 beats/min (OR, 8.72) were associated with massive transfusion. Both models had area under the curve receiver operating characteristic values of greater than 0.9 for the model and bootstrap forest analysis.

CONCLUSION

In the body region injury scale model, explosive mechanisms, serious extremity injuries, and tachycardia were most strongly associated with massive transfusion. In the simplified model, major amputations, tourniquet application, and tachycardia were most strongly associated.

Vital sign thresholds predictive of death in the combat setting

INTRODUCTION

Identifying patients at imminent risk of death is a paramount priority in combat casualty care. This study measures the vital sign values predictive of mortality among combat casualties in Iraq and Afghanistan.

METHODS

We used data from the Department of Defense Trauma Registry from January 2007 to August 2016. We used the highest documented heart rate and the lowest documented systolic pressure in the emergency department for each casualty. We constructed receiver operator curves (ROCs) to assess the accuracy of these variables for predicting survival to hospital discharge.

RESULTS

There were 38,769 encounters of which our dataset included 15,540 (40.1%). The median age of these patients was 25 years and 97.5% were male. The most common mechanisms of injury were explosives (n = 9481, 61.0%) followed by gunshot wounds (n = 2393, 15.3%). The survival rate to hospital discharge was 97.5%. The median heart rate was 94 beats per minute (bpm) with area under the ROC of 0.631 with an optimal threshold to predict mortality of 110 bpm (sensitivity 52.2%, specificity 79.2%). The median systolic blood pressure was 128 mmHg with area under the ROC of 0.790 with an optimal threshold to predict mortality of 112 mmHg (sensitivity 68.5%, specificity 81.5%).

CONCLUSIONS

Casualties with a systolic blood pressure <112 mmHg, are at high risk of mortality, a value significantly higher than the traditional 90 mmHg threshold. Our dataset highlights the need for better methods to guide resuscitation as vital sign measurements have limited accuracy in predicting mortality.

U.S. Military Medical Evacuation and Prehospital Care of Pediatric Trauma Casualties in Iraq and Afghanistan

Background: Traumatic injuries were the most common reason for pediatric admission to military hospitals during the recent wars in the Middle East. We describe injury characteristics and prehospital interventions performed on wartime pediatric trauma casualties in Afghanistan and Iraq, stratified by medical evacuation platform. Methods: We queried the Department of Defense Trauma Registry (DODTR) for all pediatric (age < 18 years) encounters from January 2007 to January 2016. The DODTR is the data repository for all trauma-related injuries managed by deployed US military medical treatment facilities with surgical capabilities. We requested all documented prehospital care, which may have been delivered anywhere from the point-of-injury until a fixed-facility with surgical capabilities. We stratified subjects according to Centers for Disease Control age groupings: <1 year, 1-4 years, 5-9 years, 10-14 years, and 15-17 years. Results: Of the 3,493 pediatric encounters in the DODTR, 1,004 underwent military evacuation from the point of injury: 911 (90.7%) by standard medical evacuation platforms and 93 (9.3%) by nonstandard, improvised evacuation assets. Six hundred seventy-five of the 1004 pediatric trauma casualties were between 5 and 14 years of age. Over 75% were male, over 80% were in Afghanistan, and most were injured by explosives. Across all age groups, serious injuries to the head/neck and extremities were most common. Subjects transported by standard evacuation platforms underwent tourniquet application (12.2% vs 5.3%, p < 0.05) and intraosseous access (12.2% vs 4.3%; p = 0.02) more frequently than those on nonstandard platforms. Casualties evacuated by nonstandard platforms underwent airway adjunct emplacement more frequently those on standard evacuation assets (3.2% vs 0.3%; p = 0.01). IV access and opiate administration were the most commonly performed interventions on both standard and nonstandard assets. Subject survival to hospital discharge was 88.1% on standard platforms and 89.2% on nonstandard platforms (p = 0.75). Conclusions: Approximately 30% of pediatric trauma casualties in Afghanistan and Iraq underwent medical evacuation from the point of injury directly to a military treatment facility with surgical capabilities. Most of those children did not undergo the prehospital interventions studied. Future investigations evaluating pediatric medical evacuation and prehospital care, medical staffing, pediatric-specific training, and equipping of pediatric-specific materials may be beneficial.

The US military experience with THAM

BACKGROUND

Acidosis, a part of the lethal trauma triad, occurs frequently after major combat trauma. Tris-hydroxymethyl aminomethane (THAM) has been used to effectively treat acidosis in injured casualties. No research has been conducted assessing the safety of THAM in the military combat setting. We sought to describe the US military experience with THAM administration to battlefield injury subjects.

METHODS

We conducted a retrospective descriptive cohort study reviewing the trauma data from the Department of Defense Trauma Registry. US military personnel with an injury severity score greater than 15, between September 2001 and December 2014, were analyzed. Our primary outcome was the 30-day all-cause mortality among cohort treated with THAM versus those who were not. Differences between the cohort were examined using a student t-test (continuous variables), Wilcoxon Rank Sum test (ordinal variables), and chi-squared test (nominal variables).

RESULTS

4558 subjects met the inclusion criteria. 69 received THAM and 4489 did not. Casualties receiving THAM had higher mean ISS scores (33 vs. 27, p < 0.001), and required significantly higher amounts of packed red blood cells (RBCs, 37 vs. 10, p < 0.001). THAM cohort had longer ventilator and intensive care unit (ICU) days with an overall lower survival to hospital discharge. On univariable analysis, THAM was associated with lower odds of survival (OR 0.18, 95% CI 0.11-0.31) but on multivariable analysis, when controlling for confounders, THAM use was not associated with a worse odds of survival (OR 0.83, 95% CI 0.21-3.24).

CONCLUSIONS

Within our combat trauma population, we were unable to detect worse 30 day mortality associated with THAM administration. Prospective investigations are needed to validate its use in critically injured combat casualties.

An analysis of the incidence of hypothermia in casualties presenting to emergency departments in Iraq and Afghanistan

INTRODUCTION

Hypothermia on the battlefield has been shown to be associated with severe injury and higher mortality. The incidence of battlefield casualties presenting with hypothermia are described.

METHODS

The Department of Defense Trauma Registry (DoDTR) was queried from January 2007 to August 2016. We identified casualties with a documented temperature of <32°Celsius (C) (severe), 32-33.9 °C (moderate), 34-36 °C (mild). We defined serious injuries as those resulting in an AIS of ≥3 by body region.

RESULTS

There were 25,484 records with at least one documented temperature and 2501 (9.8%) casualties with hypothermia within our range. Nineteen (0.75%) casualties presented with severe hypothermia, 225 (9%) with moderate, and 2257 (90%) with mild. The mean injury severity score (ISS) for non-hypothermic, mild, moderate, and severe hypothermic casualties was 8 [4-14], 14 [6-24], 21 [13-29], and 21 [9-25], (p <0.001), respectively. Survival for casualties with severe hypothermia was 57.8%, moderate 80.9%, mild hypothermia 90.9%, and non-hypothermic group 97.6%, p<0.001. When adjusting for composite injury score, patient category, mechanism of injury, and location, this finding remained significant (OR 0.27, 0.21-0.34, p<0.001). Massive transfusion was more common in hypothermia casualties n = 566 (19%) versus non-hypothermic recipients n = 1734 (6.9%), p <0.001.

CONCLUSIONS

Though the number of casualties that presented hypothermic was small, their injuries were more severe, and were more likely to receive massive blood transfusions. This cohort also had a higher mortality rate, a finding which held when adjusting for confounders. There appears to be an opportunity to improve hypothermia prevention for combat.

Pediatric Trauma Patient Intensive Care Resource Utilization in U.S. Military Operations in Iraq and Afghanistan

Children represent a unique patient population treated by military personnel during wartime, as seen in the recent conflicts in Iraq and Afghanistan. We sought to describe ICU resource utilization by U.S. military personnel treating pediatric trauma patients in Iraq and Afghanistan.

Incidence of Hyperoxia in Combat Wounded in Iraq and Afghanistan: A Potential Opportunity for Oxygen Conservation

INTRODUCTION

Oxygen supplementation is frequently used in critically injured trauma casualties in the combat setting. Oxygen supplies in the deployed setting are limited so excessive use of oxygen may unnecessarily consume this limited resource. We describe the incidence of supraphysiologic oxygenation (hyperoxia) within casualties in the Department of Defense Trauma Registry (DoDTR).

METHODS

This is a subanalysis of previously published data from the DoDTR - we isolated casualties with a documented arterial blood gas (ABG) and categorized hyperoxia as an arterial oxygen >100 mmHg and extreme hyperoxia > 300 mmHg (a subset of hyperoxia). We defined serious injuries as those with an Abbreviated Injury Score (AIS) of 3 or greater. We defined a probable moderate traumatic brain injury of those with an AIS of 3 or greater for the head region and at least one Glasgow Coma Scale at 8 or less.

RESULTS

Our initial search yielded 28,222 casualties, of which 10,969 had at least one ABG available. Within the 10,969, the proportion of casualties experiencing hyperoxia in this population was 20.6% (2,269) with a subset of 4.1% (452) meeting criteria for extreme hyperoxia. Among those with hyperoxia, the median age was 25 years (IQR 21-30), most were male (96.8%), most frequently US forces (41.4%), injured in Afghanistan (68.3%), injured by explosive (61.1%), with moderate injury scores (median 17, IQR 10-26), and most (93.8%) survived to hospital discharge. A total of 17.8% (1,954) of the casualties underwent endotracheal intubation: 27.5% (538 of 1,954) prior to emergency department (ED) arrival and 72.5% (1,416 of 1,954) within the ED. Among those intubated in the prehospital setting, upon ED arrival 35.1% (189) were hyperoxic, and a subset of 5.6% (30) that were extremely hyperoxic. Among those intubated in the ED, 35.4% (502) were hyperoxic, 7.9% (112) were extremely hyperoxic. Within the 1,277 with a probable TBI, 44.2% (565) experienced hyperoxia and 9.5% (122) met criteria for extreme hyperoxia.

CONCLUSIONS

In our dataset, more than 1 in 5 casualties overall had documented hyperoxia on ABG measurement, 1 in 3 intubated casualties, and almost 1 in 2 TBI casualties. With limited oxygen supplies in theater and logistical challenges with oxygen resupply, efforts to avoid unnecessary oxygen supplementation may have material impact on preserving this scarce resource and avoid potential detrimental clinical effects from supraphysiologic oxygen concentrations.

An Analysis of Adherence to Tactical Combat Casualty Care Guidelines for the Administration of Tranexamic Acid

BACKGROUND

Hemorrhage is the leading cause of potentially survivable deaths in combat. Previous research demonstrated that tranexamic acid (TXA) administration decreased mortality among casualties. For casualties expected to receive a transfusion, the Committee on Tactical Combat Casualty Care (TCCC) recommends TXA. Despite this, the use and adherence of TXA in the military prehospital combat setting, in accordance with TCCC guidelines, is low.

OBJECTIVES

We sought to analyze TXA administration and use among combat casualties reasonably expected to require blood transfusion, casualties with tourniquet placement, amputations, and gunshot wounds.

METHODS

Based on TCCC guidelines, we measured proportions of patients receiving prehospital TXA: casualties undergoing tourniquet placement, casualties sustaining amputation proximal to the phalanges, patients sustaining gunshot wounds, and patients receiving ≥10 units of blood products within 24 h of injury. Univariable and multivariable analyses were also completed.

RESULTS

Within our dataset, 255 subjects received TXA. Four thousand seventy-one subjects had a tourniquet placed, of whom 135 (3.3%) received prehospital TXA; 1899 subjects had an amputation proximal to the digit with 106 (5.6%) receiving prehospital TXA; and 6660 subjects had a gunshot wound with 88 (1.3%) receiving prehospital TXA. Of 4246 subjects who received ≥10 units of blood products within the first 24 h, 177 (4.2%) received prehospital TXA.

CONCLUSIONS

We identified low TXA administration despite TCCC recommendations. Future studies should seek to both identify reasons for limited TXA administration and methods to increase future utilization.

Damage control resuscitation and surgery for indigenous combat casualties: a prospective observational study

INTRODUCTION

Specialist units that assist indigenous forces (IF) in their strategic aims are supported by medical teams providing point of injury emergency care for casualties, including IF and civilians (Civ). We investigated the activities of a Coalition Forces far-forward medical facility, in order to inform medical providers about the facilities and resources required for medical support to IF and Civ during such operations.

METHODS

A prospective observational study (June to August 2017) undertaken at a far-forward Coalition Forces medical support unit (12 rotating personnel) recorded patient details (IF or Civ), mechanism of injury (MOI), number of blood products used, damage control resuscitation (DCR) and damage control surgery (DCS), number of mass casualty (MASCAL) scenarios, resuscitative thoracotomy, resuscitative endovascular balloon occlusion of the aorta (REBOA) and whole blood emergency donor panels (EDP).

RESULTS

680 casualties included 478 IF and 202 Civ (45.5% of the Civ were paediatric). Most common MOIs were blast (n=425; 62.5%) and gunshot wound (n=200; 29.4%). Fifteen (2.2%) casualties died; 627 (92.2%) were transferred to local hospitals. DCR was used for 203 (29.9%), and DCS for 182 (26.8%) casualties. There were 23 MASCAL scenarios, 1220 transfusions and 32 EDPs. REBOA was performed eight times, and thoracotomy was performed 27 times.

CONCLUSIONS

A small medical team provided high-tempo emergency resuscitative care for hundreds of IF and Civ casualties within a short space of time using state-of-the-art resuscitative modalities. DCR and DCS were undertaken with a large number of EDPs, and a high survival-to-transfer rate.

Thoracic trauma in military settings: a review of current practices and recommendations

PURPOSE OF REVIEW

To examine current literature on thoracic trauma related to military combat and to explore its relevance to the civilian population.

RECENT FINDINGS

Damage control resuscitation (DCR) has improved the management of hemorrhaging trauma patients. Permissive hypotension below 110 mmHg and antifibrinolytic use during DCR is widely accepted, whereas the use of freeze-dried plasma and whole blood is gaining popularity. The Modified Physiologic Triaging Tool can be used for primary triage and it may have applications in civilian trauma systems. Although Tactical Combat Casualty Care protocol recommends the Cric-Key device for surgical cricothyroidotomies, other devices may offer comparable performance. Recommendations for regional anesthesia after blunt trauma are not well defined. Increasing amounts of evidence favor the use of extracorporeal membrane oxygenation for refractory hypoxemia and resuscitative endovascular balloon occlusion of the aorta (REBOA) for severe hemorrhage. REBOA outcomes are potentially improved by partial occlusion and small 7 Fr catheters.

SUMMARY

The Global War on Terror has provided opportunities to better understand and treat thoracic trauma in military settings. Trauma registries and other data sources have contributed to significant advancements in the management of thoracic trauma in military and civilian populations.