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.

Prospective Randomized Trial of Standard Left Anterolateral Thoracotomy Versus Modified Bilateral Clamshell Thoracotomy Performed by Emergency Physicians.

STUDY OBJECTIVE: Resuscitative thoracotomy is a time-sensitive, lifesaving procedure that may be performed by emergency physicians. The left anterolateral thoracotomy (LAT) is the standard technique commonly used in the United States to gain rapid access to critical intrathoracic structures. However, the smaller incision and subsequent limited exposure may not be optimal for the nonsurgical specialist to complete time-sensitive interventions. The modified bilateral anterior clamshell thoracotomy (MCT) developed by Barts Health NHS Trust clinicians at London's Air Ambulance overcomes these inherent difficulties, maximizes thoracic cavity visualization, and may be the ideal technique for the nonsurgical specialist. The aim of this study is to identify the optimal technique for the nonsurgical-specialist-performed resuscitative thoracotomy. Secondary aims of the study are to identify technical difficulties, procedural concerns, and physician preferences. METHODS: Emergency medicine staff and senior resident physicians were recruited from an academic Level I trauma center. Subjects underwent novel standardized didactic and skills-specific training on both the MCT and LAT techniques. Later, subjects were randomized to the order of intervention and performed both techniques on separate fresh, nonfrozen human cadaver specimens. Success was determined by a board-certified surgeon and defined as complete delivery of the heart from the pericardial sac and subsequent 100% occlusion of the descending thoracic aorta with a vascular clamp. The primary outcome was time to successful completion of the resuscitative thoracotomy technique. Secondary outcomes included successful exposure of the heart, successful descending thoracic aortic cross clamping, successful procedural completion, time to exposure of the heart, time to descending thoracic aortic cross-clamp placement, number and type of iatrogenic injuries, correct anatomic structure identification, and poststudy participant questionnaire. RESULTS: Sixteen emergency physicians were recruited; 15 met inclusion criteria. All participants were either emergency medicine resident (47%) or emergency medicine staff (53%). The median number of previously performed training LATs was 12 (interquartile range 6 to 15) and the median number of previously performed MCTs was 1 (interquartile range 1 to 1). The success rates of our study population for the MCT and LAT techniques were not statistically different (67% versus 40%; difference 27%; 95% confidence interval -61% to 8%). However, staff emergency physicians were significantly more successful with the MCT compared with the LAT (88% versus 25%; difference 63%; 95% CI 9% to 92%). Overall, the MCT also had a significantly higher proportion of injury-free trials compared with the LAT technique (33% versus 0%; difference 33%; 95% CI 57% to 9%). Physician procedure preference favored the MCT over the LAT (87% versus 13%; difference 74%; 95% CI 23% to 97%). CONCLUSION: Resuscitative thoracotomy success rates were lower than expected in this capable subject population. Success rates and procedural time for the MCT and LAT were similar. However, the MCT had a higher success rate when performed by staff emergency physicians, resulted in less periprocedural iatrogenic injuries, and was the preferred technique by most subjects. The MCT is a potentially feasible alternative resuscitative thoracotomy technique that requires further investigation.

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.

A systematic review of penetrating extracranial vertebral artery injuries.

BACKGROUND: Penetrating vertebral artery injuries (VAIs) are rare. Because of their rarity, complex anatomy, and difficult surgical exposures, few surgeons and trauma centers have developed significant experience with their management. The objectives of this study were to review their incidence, clinical presentation, radiologic identification, management, complications, and outcomes and to provide a review of anatomic exposures and surgical techniques for their management. METHODS: A literature search on MEDLINE Complete-PubMed, Cochrane, Ovid, and Embase for the period of 1893 to 2018 was conducted. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used. Our literature search yielded a total of 181 potentially eligible articles with 71 confirmed articles, consisting of 21 penetrating neck injury series, 13 VAI-specific series, and 37 case reports. Operative procedures and outcomes were recorded along with methods of angiographic imaging and operative management. All articles were reviewed by at least two independent authors, and data were analyzed collectively. RESULTS: There were a total of 462 patients with penetrating VAIs. The incidence of VAI in the civilian population was 3.1% vs 0.3% in the military population. More complete data were available from 13 collected VAI-specific series and 37 case reports for a total of 362 patients. Mechanism of injury data were available for 341 patients (94.2%). There were gunshot wounds (178 patients [49.2%]), stab wounds (131 [73.6%]), and miscellaneous mechanisms of injury (32 [8.8%]). Anatomic site of injury data were available for 177 (49%) patients: 92 (25.4%) left, 84 (23.2%) right, and 1 (0.3%) bilateral. Anatomic segment of injury data were available for 204 patients (56.4%): 28 (7.7%) V1, 125 (34.5%) V2, and 51 (14.1%) V3. Treatment data were available for 212 patients. Computed tomography angiography was the most common imaging modality (163 patients [77%]). Injuries were addressed by operative management (94 [44.3%]), angiography and angioembolization (72 [34%]), combined approaches (11 [5.2%]), and observation (58 [27.4%]). Stenting and repair were less frequently employed (10 [4.7%]). The incidence of aneurysms or pseudoaneurysms was 18.5% (67); the incidence of arteriovenous fistula was 16.9% (61). The calculated mortality in VAI-specific series was 15.1%; in the individual case report group, it was 10.5%. CONCLUSIONS: The majority of VAIs present without neurologic symptoms, although some may present with exsanguinating hemorrhage. Computed tomography angiography should be considered first line to establish diagnosis. Gunshot wounds account for most injuries. The most frequently injured segment is V2. Surgical ligation is the most common intervention, followed by angioembolization, both of which constitute important management approaches.

An analysis of the pediatric casualties undergoing massive transfusion in Iraq and Afghanistan.

BACKGROUND: Existing data on pediatric massive transfusion as part of trauma resuscitation is limited. We report the characteristics of pediatric casualties associated with undergoing massive transfusion at US military treatment facilities during combat operations in Iraq and Afghanistan. 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. We stratified subjects by Centers for Disease Control age groupings: <1, 1-4, 5-9, 10-14, and 15-17 years. We defined a massive transfusion as 40 mL/kg of total blood products or more. RESULTS: From January 2007 through January 2016 there were 3439 pediatric casualties within the registry, of which 543 (15.7%) met criteria for receiving a massive transfusion. The median age of children undergoing massive transfusion was 9 years (IQR 5-12), male (73.4%), injured in Afghanistan (69.9%) and injured by explosives (60.4%). Compared to other pediatric casualties, subjects undergoing massive transfusion had higher composite injury severity scores (median 17 versus 9), higher incidence of tachycardia (86.8% versus 70.9%), increased incidence of hypotension (31.2% versus 7.5%), and decreased survival to hospital discharge (82.6% versus 91.6%). Specific to body regions, casualties undergoing massive transfusion more frequently had serious injuries to the head/neck (30.0% versus 22.8%), the thorax (22.8% versus 9.9%), abdomen (26.8% versus 6.9%), the extremities (42.1% versus 14.6%), while less frequently had serious injuries to the skin (5.3% versus 8.4%). All findings were significant. CONCLUSIONS: Further research is needed to better translate the lessons learned from pediatric trauma care in the combat setting into the civilian setting in developed countries. LEVEL OF EVIDENCE: 3.

Incidence of Pediatric Cervical Spine Injuries in Iraq and Afghanistan.

OBJECTIVE: Military providers frequently treat civilians, including pediatric patients. Cervical spine injuries in pediatric trauma patients occur infrequently, with limited data on the incidence. The aim of this study was to describe the incidence of cervical spine injuries in pediatric patients in Iraq and Afghanistan. METHODS: We queried the Department of Defense Trauma Registry for all pediatric encounters from January 2007 to January 2016. We searched within that dataset for all cervical spine fractures. RESULTS: From January 2007 through January 2016 there were 3439 pediatric encounters. There were 36 subjects identified (1.0%) with a cervical spine fracture. Of those with a cervical spine fracture, 6 (17%) had a prehospital cervical collar placed, which did not improve survival to hospital discharge (collar, 66.7% vs no collar, 83.3%, P = 0.573). Of those with a cervical spine fracture, 6 (17%) had a documented spinal cord injury. The median age of subjects with a cervical spine fracture was 9.5 years and the majority (63.9%) were male. Most were injured by explosion (41.7%). The median composite injury score was higher in subjects with a cervical spine fracture compared with those without one (16.5 vs 10, P < 0.001). Subjects with a cervical spine fracture had longer lengths of stay in the intensive care unit (median 3 days vs 1, P = 0.012) and a trend toward worse survival to hospital discharge (80.6%, n = 29, vs 90.3%, n = 3074, P = 0.079). CONCLUSIONS: Cervical spine injuries occurred infrequently in pediatric patients in Iraq and Afghanistan. When a fracture was present, almost one in five patients had spinal cord involvement. The pediatric prehospital literature would benefit from the development of a clinical decision tool to guide prehospital personnel as to when a cervical collar is indicated. Moreover, appropriate size equipment should be available when caring for host national civilians.

Association of time to craniectomy with survival in patients with severe combat-related brain injury.

OBJECTIVEIn combat and austere environments, evacuation to a location with neurosurgery capability is challenging. A planning target in terms of time to neurosurgery is paramount to inform prepositioning of neurosurgical and transport resources to support a population at risk. This study sought to examine the association of wait time to craniectomy with mortality in patients with severe combat-related brain injury who received decompressive craniectomy.METHODSPatients with combat-related brain injury sustained between 2005 and 2015 who underwent craniectomy at deployed surgical facilities were identified from the Department of Defense Trauma Registry and Joint Trauma System Role 2 Registry. Eligible patients survived transport to a hospital capable of diagnosing the need for craniectomy and performing surgery. Statistical analyses included unadjusted comparisons of postoperative mortality by elapsed time from injury to start of craniectomy, and Cox proportional hazards modeling adjusting for potential confounders. Time from injury to craniectomy was divided into quintiles, and explored in Cox models as a binary variable comparing early versus delayed craniectomy with cutoffs determined by the maximum value of each quintile (quintile 1 vs 2-5, quintiles 1-2 vs 3-5, etc.). Covariates included location of the facility at which the craniectomy was performed (limited-resource role 2 facility vs neurosurgically capable role 3 facility), use of head CT scan, US military status, age, head Abbreviated Injury Scale score, Injury Severity Score, and injury year. To reduce immortal time bias, time from injury to hospital arrival was included as a covariate, entry into the survival analysis cohort was defined as hospital arrival time, and early versus delayed craniectomy was modeled as a time-dependent covariate. Follow-up for survival ended at death, hospital discharge, or hospital day 16, whichever occurred first.RESULTSOf 486 patients identified as having undergone craniectomy, 213 (44%) had complete date/time values. Unadjusted postoperative mortality was 23% for quintile 1 (n = 43, time from injury to start of craniectomy 30-152 minutes); 7% for quintile 2 (n = 42, 154-210 minutes); 7% for quintile 3 (n = 43, 212-320 minutes); 19% for quintile 4 (n = 42, 325-639 minutes); and 14% for quintile 5 (n = 43, 665-3885 minutes). In Cox models adjusted for potential confounders and immortal time bias, postoperative mortality was significantly lower when time to craniectomy was within 5.33 hours of injury (quintiles 1-3) relative to longer delays (quintiles 4-5), with an adjusted hazard ratio of 0.28, 95% CI 0.10-0.76 (p = 0.012).CONCLUSIONSPostoperative mortality was significantly lower when craniectomy was initiated within 5.33 hours of injury. Further research to optimize craniectomy timing and mitigate delays is needed. Functional outcomes should also be evaluated.

A Descriptive Analysis of Blood Products Utilized by a Forward Deployed Surgical Team in Syria.

INTRODUCTION: Traumatically injured combat casualties urgently need both blood and surgery. Forward Surgical Teams (FSTs) or Role 2 (R2) surgical teams were created to minimize the time-space distance from point of injury to damage control surgery. Our goal is to describe the use of blood products from a Split FST deployed to Green Village from July 2018 to April 2019. MATERIALS AND METHODS: A retrospective review of a collection of patients treated by a single R2 was conducted following institutional regulatory approval. De-identified data were input into the study database and were then retrospectively reviewed for patients who presented to and received treatment at the R2 facility. RESULTS: Of the 470 total patients treated in 10 months: 226 (48%) received blood products and 132 (28%) underwent operative procedures. The patients were 98% male; 74% Host Nationals (HN), 24% North American Treaty Organization members. Mechanism of injury was 75% explosive and 98% penetrating. Documented Injury Severity Scores (n = 214) were: <9 (n = 57/27%), 9 to 15 (n = 34/16%), 16 to 25 (n = 64/30%), and >25 (n = 59/28%). In total 1,052 units of blood products were administered: whole blood (n = 495), red blood cells (n = 200), fresh frozen plasma (n = 109), and liquid plasma (n = 248). HN whole blood used was 337/495 (68%) units for 78 patients; walking blood bank was mobilized six times for HN patients. Of the patients seen, >99% who arrived with a pulse survived to be discharged to a higher level of care. CONCLUSIONS: This analysis describes blood usage associated with one high volume forward deployed operative team and demonstrates the vital importance of the R2 split FST to provide coalition forces with surgical care in proximity to the point of injury. Over time, the supply chain has improved with more component therapy available at R2s; however, the need for walking blood bank and innovative solutions to care for all casualties must be part of small team capabilities. Liquid plasma use should be expanded as soon as it is feasible.

Incidence of Airway Interventions in the Setting of Serious Facial Trauma.

BACKGROUND: Airway obstruction is the second leading cause of preventable death on the battlefield. Most airway obstruction occurs secondary to traumatic disruptions of the airway anatomical structures. Facial trauma is frequently cited as rationale for maintaining cricothyrotomy in the medics' skill set over the supraglottic airways more commonly used in the civilian setting. METHODS: We used a series of emergency department procedure codes to identify patients within the Department of Defense Trauma Registry (DoDTR) from January 2007 to August 2016. This is a sub-group analysis of casualties with documented serious facial trauma based on an abbreviated injury scale of 3 or greater for the facial body region. RESULTS: Our predefined search codes captured 28,222 DoDTR casualties, of which we identified 136 (0.5%) casualties with serious facial trauma, of which 19 of the 136 had documentation of an airway intervention (13.9%). No casualties with serious facial trauma underwent nasopharyngeal airway (NPA) placement, 0.04% underwent cricothyrotomy (n = 10), 0.03% underwent intubation (n = 9), and a single subject underwent supraglottic airway (SGA) placement (<0.01%). We only identified four casualties (0.01% of total dataset) with an isolated injury to the face. CONCLUSIONS: Serious injury to the face rarely occurred among trauma casualties within the DoDTR. In this subgroup analysis of casualties with serious facial trauma, the incidence of airway interventions to include cricothyrotomy was exceedingly low. However, within this small subset the mortality rate is high and thus better methods for airway management need to be developed.

Prolonged casualty care: Extrapolating civilian data to the military context.

BACKGROUND: Civilian and military populations alike are increasingly faced with undesirable situations in which prehospital and definitive care times will be delayed. The Western Cape of South Africa has some similarities in capabilities, injury profiles, resource limitations, and system configuration to US military prolonged casualty care (PCC) settings. This study provides an initial description of civilians in the Western Cape who experience PCC and compares the PCC and non-PCC populations. METHODS: We conducted a 6-month analysis of an ongoing, prospective, large-scale epidemiologic study of prolonged trauma care in the Western Cape (Epidemiology and Outcomes of Prolonged Trauma Care [EpiC]). We define PCC as ≥10 hours from injury to arrival at definitive care. We describe patient characteristics, critical interventions, key times, and outcomes as they may relate to military PCC and compare these using χ 2 and Wilcoxon tests. We estimated the associations between PCC status and the primary and secondary outcomes using logistic regression models. RESULTS: Of 995 patients, 146 experienced PCC. The PCC group, compared with non-PCC, were more critically injured (66% vs. 51%), received more critical interventions (36% vs. 29%), and had a greater proportionate mortality (5% vs. 3%), longer hospital stays (3 vs. 1 day), and higher Sequential Organ Failure Assessment scores (5 vs. 3). The odds of 7-day mortality and a Sequential Organ Failure Assessment score of ≥5 were 1.6 (odds ratio, 1.59; 95% confidence interval, 0.68-3.74) and 3.6 (odds ratio, 3.69; 95% confidence interval, 2.11-6.42) times higher, respectively, in PCC versus non-PCC patients. CONCLUSION: The EpiC study enrolled critically injured patients with PCC who received resuscitative interventions. Prolonged casualty care patients had worse outcomes than non-PCC. The EpiC study will be a useful platform to provide ongoing data for PCC relevant analyses, for future PCC-focused interventional studies, and to develop PCC protocols and algorithms. Findings will be relevant to the Western Cape, South Africa, other LMICs, and military populations experiencing prolonged care. LEVEL OF EVIDENCE: Therapeutic/care management; Level IV.

The epidemiology and outcomes of prolonged trauma care (EpiC) study: methodology of a prospective multicenter observational study in the Western Cape of South Africa.

BACKGROUND: Deaths due to injuries exceed 4.4 million annually, with over 90% occurring in low-and middle-income countries. A key contributor to high trauma mortality is prolonged trauma-to-treatment time. Earlier receipt of medical care following an injury is critical to better patient outcomes. Trauma epidemiological studies can identify gaps and opportunities to help strengthen emergency care systems globally, especially in lower income countries, and among military personnel wounded in combat. This paper describes the methodology of the "Epidemiology and Outcomes of Prolonged Trauma Care (EpiC)" study, which aims to investigate how the delivery of resuscitative interventions and their timeliness impacts the morbidity and mortality outcomes of patients with critical injuries in South Africa. METHODS: The EpiC study is a prospective, multicenter cohort study that will be implemented over a 6-year period in the Western Cape, South Africa. Data collected will link pre- and in-hospital care with mortuary reports through standardized clinical chart abstraction and will provide longitudinal documentation of the patient's clinical course after injury. The study will enroll an anticipated sample of 14,400 injured adults. Survival and regression analysis will be used to assess the effects of critical early resuscitative interventions (airway, breathing, circulatory, and neurologic) and trauma-to-treatment time on the primary 7-day mortality outcome and secondary mortality (24-h, 30-day) and morbidity outcomes (need for operative interventions, secondary infections, and organ failure). DISCUSSION: This study is the first effort in the Western Cape of South Africa to build a standardized, high-quality, multicenter epidemiologic trauma dataset that links pre- and in-hospital care with mortuary data. In high-income countries and the U.S. military, the introduction of trauma databases and registries has led to interventions that significantly reduce post-injury death and disability. The EpiC study will describe epidemiology trends over time, and it will enable assessments of how trauma care and system processes directly impact trauma outcomes to ultimately improve the overall emergency care system. TRIAL REGISTRATION: Not applicable as this study is not a clinical trial.

A Novel Use of the Erector Spinae Block in the Austere Environment.

A 25 year-old male presented with penetrating chest trauma to a split forward surgical team located in an austere setting. Due to limited resources and a minimal monitoring in-transit a regional anesthetic was placed for pain control. This is the first description of an Erector Spinae Block utilized in a far forward combat setting.

Rare Use of Posterolateral Thoracotomy in an Austere Environment.

A 25-year-old local national male presented to a split Forward Surgical Team after impalement of the posterior chest with a metal fragment. The patient was hemodynamically normal, but no imaging was available to determine the depth of penetration or the size of the internal portion of the fragment. This case represents a rare indication for posterolateral thoracotomy in an austere trauma setting.

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.

Airway Management in the Prehospital, Combat Environment: Analysis of After-Action Reviews and Lessons Learned.

INTRODUCTION: Airway compromise is the second leading cause of potentially survivable death on the battlefield. Studies show that airway management is a challenge in prehospital combat care with high error and missed opportunity rates. Lacking is user information on the perceived reasons for the challenges. The US military uses several performance improvement and field feedback systems to solicit feedback regarding deployed experiences. We seek to review feedback and after-action reviews (AARs) from end-users with specific regard to airway challenges noted. METHODS: We queried the Center for Army Lessons Learned (CALL), the Army Medical Department Lessons Learned (AMEDDLL), and the Joint Lessons Learned Information System (JLLIS).Our queries comprised a series of search terms with a focus on airway management. Three military emergency medicine expert reviewers performed the primary analysis for lessons learned specific to deployment and predeployment training lessons learned. Upon narrowing the scope of entries to those relevant to deployment and predeployment training, a panel of eight experts performed reviews. The varied nature of the sources lent itself to an unstructured qualitative approach with results tabulated into thematic categories. RESULTS: Our initial search yielded 611 nonduplicate entries. The primary reviewers then analyzed these entries to determine relevance to the project-this resulted in 70 deployment- based lessons learned and four training-based lessons learned. The panel of eight experts then reviewed the 74 lessons learned. We categorized 37 AARs as equipment challenges/malfunctions, 28 as training/education challenges, and 9 as other. Several lessons learned specifically stated that units failed to prioritize medic training; multiple comments suggested that units should consider sending their medics to civilian training centers. Other comments highlighted equipment shortages and equipment malfunctions specific to certain mission types (e.g., pediatric casualties, extreme weather). CONCLUSIONS: In this review of military lessons learned systems, most of the feedback referenced equipment malfunctions and gaps in initial and maintenance training.This review of AARs provides guidance for targeted research efforts based the needs of the end-users.

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.

The First 30 Months Experience in the Non-Doctrinal Operation Inherent Resolve Medical Theater.

INTRODUCTION: U.S. military forces were redeployed in 2014 in support of Operation Inherent Resolve (OIR), operating in an austere theater without the benefit of an established medical system. We seek to describe the prehospital and hospital-based care delivered in this medically immature, non-doctrinal theater. MATERIALS AND METHODS: We queried the Department of Defense Trauma Registry (DODTR) for all encounters associated with OIR from August 2014 through June 2017. We sought all available prehospital and hospital-based data. RESULTS: There were a total of 826 adults that met inclusion; 816 were from Iraq and the remaining 10 were from Syria. The median age was 21 years and the most frequent mechanism of injury was explosives (47.7%). Median composite injury severity scores were low (9, IQR 2.75-14) and the most frequent seriously injured body region was the extremities (23.0%). Most subjects (94.9%) survived to hospital discharge. Open fractures were the most frequent major injury (26.0%). In the prehospital setting, opioids were the most frequently administered medication (9.3%) and warming blanket application (48.7%) and intravenous line placement (24.8%) were the most frequent interventions. In the emergency department, Focused Assessment with Sonography in Trauma exams (64.3%) was the most frequently performed study and endotracheal intubations were the most frequent (29.9%) procedure. In the operating room, the most frequently performed procedure was exploratory laparotomy (12.3%). CONCLUSIONS: Host nation military males injured by explosion comprised the majority of casualties. Open fracture was the most common major injury. Hence, future research should focus upon the unique challenges of delivering care to members of partner forces with particular focus upon interventions to optimize outcomes among patients sustaining open fractures.

A descriptive analysis of casualties evacuated from the Africa area of operations.

INTRODUCTION: The United States (US) military has expanded its area of operations into Africa. This medically immature theater is spread across a large region where prolonged field care (PFC) events are likely to occur. We describe trauma cases reported in the Africa Command (AFRICOM) area of operations to date within the Department of Defense Trauma Registry (DODTR). METHODS: We queried the DODTR for all subjects evacuated from the AFRICOM area of operations from January 2002 to June 2017. RESULTS: There were 49 subjects in the registry during our time frame from AFRICOM. Most of the evacuations came from Djibouti (53%). The median age was 29 years, most evacuees being male (92%). Non-battle injuries accounted for most of the injuries (82%), and most were US military (90%). All battle injuries were gunshot wounds (GSW). Composite injury scores were low (median 4, IQR 4-9.5). All subjects survived to hospital discharge. GSWs (22%) and sports injuries (24%) accounted for most evacuations. Serious injuries most frequently involved the extremities (18%) and the thorax (12%). The most frequent major injuries were open fractures (22%) and abdominal injuries (10%). The most frequent facility-based interventions performed were wound debridement (29%) and fracture/joint dislocation reduction (22%). DISCUSSION: Based on this dataset, most of the injuries from AFRICOM were non-battle injuries. All battle injuries were GSWs. Our study highlights the differences in casualty care needs in this region which contrast the primary explosive-based injuries seen within United States Central Command (CENTCOM) operations. The limitations of this dataset highlight the potential value of a Joint Trauma Service (JTS) data collection mandate and resource support for units within this region to facilitate targeted improvements in medical care.

The genomic heritage of lymph node metastases: implications for clinical management of patients with breast cancer.

BACKGROUND: Metastatic breast cancer is an aggressive disease associated with recurrence and decreased survival. To improve outcomes and develop more effective treatment strategies for patients with breast cancer, it is important to understand the molecular mechanisms underlying metastasis. METHODS: We used allelic imbalance (AI) to determine the molecular heritage of primary breast tumors and corresponding metastases to the axillary lymph nodes. Paraffin-embedded samples from primary breast tumors and matched metastases (n = 146) were collected from 26 patients with node-positive breast cancer involving multiple axillary nodes. Hierarchical clustering was used to assess overall differences in the patterns of AI, and phylogenetic analysis inferred the molecular heritage of axillary lymph node metastases. RESULTS: Overall frequencies of AI were significantly higher (P < 0.01) in primary breast tumors (23%) than in lymph node metastases (15%), and there was a high degree of discordance in patterns of AI between primary breast carcinomas and the metastases. Metastatic tumors in the axillary nodes showed different patterns of chromosomal changes, suggesting that multiple molecular mechanisms may govern the process of metastasis in individual patients. Some metastases progressed with few genomic alterations, while others harbored many chromosomal alterations present in the primary tumor. CONCLUSIONS: The extent of genomic heterogeneity in axillary lymph node metastases differs markedly among individual patients. Genomic diversity may be associated with response to adjuvant therapy, recurrence, and survival, and thus may be important in improving clinical management of breast cancer patients.

Genomic instability and the development of metastatic lymph node tumors.

BACKGROUND: Although recent data suggest that cells with metastatic potential disseminate from the primary breast tumor early in tumor development, the mechanism by which disseminated breast cancer cells proliferate within foreign tissues is not well understood. Here, we examined levels and patterns of allelic imbalance (AI) in metastatic lymph node (LN) tumors to identify molecular signals that promote the survival and growth of disseminated breast tumor cells. METHODS: DNA from 106 metastatic LN tumors from 25 patients was isolated after laser microdissection of pure tumor cell populations. AI was assessed at 26 chromosomal regions frequently altered in breast cancer. Tumor burden was calculated by dividing the area of the metastatic tumor in the node by the area of the entire LN. RESULTS: Metastatic tumor burden ranged from focal to complete replacement of the LN with tumor. Grouping the nodes as < 25% tumor, 25-50% tumor, 50-75% tumor, and > or = 75% tumor replacement revealed the average frequency of AI ranged from 0.13 (+/-0.11) in the < 25% group to 0.17 (+/-0.13) in LNs with > or = 75% tumor burden. The range of AI in both the < 25% and > 75% replacement group was 0.00-0.48. Allelic losses at chromosomal regions 1p36.1-36.2, 5q21.1-21.3, 6q15, 10q23.31-23.33, and 17p13.1 were significantly higher in metastatic LNs with > 75% compared with < 25% tumor burden. CONCLUSIONS: In metastatic LNs, levels of AI were not associated with tumor burden, suggesting that accumulation of genetic changes is not coincidental with tumor growth; rather the accumulation of specific genetic changes is a prerequisite to the transformation of disseminated breast cells into metastatic LN tumors.