Casualty Lessons Learned, Trends, and Statistics

#### COMBAT CASUALTY CARE LESSONS LEARNED / CASE REPORTS

Ann Surg. 2018 Epub ahead of print

# Vascular surgery in the Pacific theaters of World War II: the persistence of ligation amid unique military medical conditions.

Barr J, Cherry K, Rich N

Although multiple sources chronicle the practice of vascular surgery in the North African, Mediterranean, and European theaters of World War II, that of the Pacific campaign remains undescribed. Relying on primary source documents from the war, this article provides the first discussion of the management of vascular injuries in the island-hopping battles of the Pacific. It explains how the particular military, logistic, and geographic conditions of this theater influenced medical and surgical care, prompting a continued emphasis on ligation when surgeons in Europe had already transitioned to repairing arteries.

Emerg Med Australas. 2018 Oct;30(5):722-724. doi: 10.1111/1742-6723.13091. Epub 2018 May 9.

# Preparedness for treating victims of terrorist attacks in Australia: learning from recent military experience.

Rosenfeld J, Mitra B, Smit V, Fitzgerald M, Butson B, Stephenson M, Reade M

The Australian health system is generally well prepared for mass casualty events. Fortunately, there have been very few terrorist attacks and these have involved low numbers of casualties compared with events overseas. Nevertheless, Australian health professionals need to be prepared to treat mass casualties with blast and ballistic trauma. The US military and its allies including Australia have had extensive experience with mass casualty management in the Middle East and Afghanistan wars for more than a decade. To define their experience, they developed the Tactical Combat Casualty Care Guidelines that have saved many lives. It is now prudent to incorporate this knowledge and experience into civilian practice in Australia.

#### CASUALTY TRENDS & STATISTICS

J Trauma Acute Care Surg. 2018 Jun;84(6):893-899

# The contemporary timing of trauma deaths.

Bardes J, Inaba K, Schellenberg M, Grabo D, Strumwasser A, Matsushima K, Clark D, Brown N, Demetriades D.

BACKGROUND: The distribution of trauma deaths was classically described as trimodal. With advances in both technology and trauma systems, this was reevaluated and found to be bimodal in the early 2000s. Over the last decade there have been continued improvements in trauma and intensive care unit (ICU) care, related to damage control techniques and evidence based ICU pathways. A better understanding of the distribution of trauma deaths may be used to improve trauma systems. This study aimed to evaluate the contemporary distribution of trauma deaths after the widespread implementation of modern trauma and critical care principles.

METHODS: This study included patients entered in the NTDB from 2008 to 2014. For dead patients, hospital length of stay was equated to time until death. Additional data was collected to include demographics, mechanism of injury, Injury Severity Score, and Abbreviated Injury Scale score. Histograms were plotted to demonstrate peaks in deaths. Survival analysis was performed with Kaplan-Meier curves and Gehan-Breslow generalized Wilcoxon tests.

RESULTS: 4,185,009 patients were analyzed. Thirty-four percent of all deaths occurred within the first 24 hours of admission. The factors most associated with death in the first 24 hours were severe abdominal trauma (73%), penetrating trauma (55%), and severe extremity trauma (58%). Among patients with penetrating trauma and an abdominal Abbreviated Injury Scale score of 4 or higher, 83% of deaths occurred within 24 hours. When plotted, the distribution of deaths was seen to fall rapidly after the first 24 hours and continued to be flat for 30 days in all subgroups analyzed.

CONCLUSION: In this study, the distribution of trauma deaths no longer appears to be trimodal. This may reflect advances in trauma and ICU care, and the widespread adaption of damage control principles. Early deaths, however, remains a significant challenge, specifically from non-compressible abdominal hemorrhage and extremity trauma. Primary prevention and early hemorrhage control must continue to be a focus of research and trauma systems.

LEVEL OF EVIDENCE: Epidemiologic, level IV.

Ann Surg. 2018 Jul 31. doi: 10.1097/SLA.0000000000002999. [Epub ahead of print]

# Establishing a regional trauma preventable/potentially preventable death rate.

Drake S, Holcomb J, Yang Y, Thetford C, Myers L, Brock M, Wolf D, Cron S, Persse D, McCarthy J, Kao L, Todd S, Naik-Mathuria B, Cox C, Kitagawa R, Sandberg G, Wade C

OBJECTIVE: To establish a trauma preventable/potentially preventable death rate (PPPDR) within a heavily populated county in Texas.

SUMMARY: The National Academies of Sciences estimated the trauma preventable death rate in the United States to be 20%, issued a call for zero preventable deaths, while acknowledging that an accurate preventable death rate was lacking. In this absence, effective strategies to improve quality of care across trauma systems will remain difficult.

METHODS: A retrospective review of death-related records that occurred during 2014 in Harris County, TX, a diverse population of 4.4 million. Patient demographics, mechanism of injury, cause, timing, and location of deaths were assessed. Deaths were categorized using uniform criteria and recorded as preventable, potentially preventable or nonpreventable.

RESULTS: Of 1848 deaths, 85% had an autopsy and 99.7% were assigned a level of preventability, resulting in a trauma PPPDR of 36.2%. Sex, age, and race/ethnicity varied across preventability categories (P < 0.01). Of 847 prehospital deaths, 758 (89.5%) were nonpreventable. Among 89 prehospital preventable/potentially preventable (P/PP) deaths, hemorrhage accounted for 55.1%. Of the 657 initial acute care setting deaths, 292 (44.4%) were P/PP; of these, hemorrhage, sepsis, and traumatic brain injury accounted for 73.3%. Of 339 deaths occurring after initial hospitalization, 287 (84.7%) were P/PP, of these 117 resulted from sepsis and 31 from pulmonary thromboembolism, accounted for 51.6%.

CONCLUSIONS: The trauma PPPDR was almost double that estimated by the National Academies of Sciences. Data regarding P/PP deaths offers opportunity to target research, prevention, intervention, and treatment corresponding to all phases of the trauma system.

Trauma Surg Acute Care Open. 2017 May 31;2(1):e000106. doi: 10.1136/tsaco-2017-000106. eCollection 2017.

# Methodology to reliably preventable trauma measure death rate.

Drake S, Wolf D, Meininger J, Cron S, Reynold T, Wade C, Holcomb J.

This article describes a methodology to establish a trauma preventable death rate(PDR) in a densely populated county in the USA. Harris County has >4 million residents, encompasses a geographic area of 1777 square miles and includes the City of Houston, Texas. Although attempts have been made to address a national PDR, these studies had significant methodological flaws. There is no national consensus among varying groups of clinicians for defining preventability or documenting methods by which preventability is determined. Furthermore, although trauma centers routinely evaluate deaths within their hospital for preventability, few centers compare across regions, within the prehospital arena and even fewer have evaluated trauma deaths at non-trauma centers. Comprehensive population-based data on all trauma deaths within a defined region would provide a framework for effective prevention and intervention efforts at the regional and national levels. The authors adapted a military method recently used in Southwest Asia to determine the potential preventability of civilian trauma deaths occurring across a large and diverse population. The project design will allow a data-driven approach to improve services across the entire spectrum of trauma care, from prevention through rehabilitation.

Injury. 2018 May 22. pii: S0020-1383(18)30257-2

# A preliminary study into injuries due to non-perforating ballistic impacts into soft body armour over the spine.

Jennings R, Malbon C, Brock F, Harrisson S, Carr D

The UK Home Office test method for ballistic protective police body armours considers anterior torso impacts to be the worst-case scenario and tests rear armour panels to the same standards as front panels. The aim of this paper was to examine the injuries from spinal behind armour blunt trauma (BABT) impacts. This study used a cadaveric 65 kg, female pig barrel and 9 mm Luger ammunition (9 × 19 mm, FMJ Nammo Lapur Oy) into HG1/A + KR1 soft armour panels over the spine. Injuries were inspected and sections removed for x-radiography and micro-CT assessment. All shots over the spine resulted in deep soft tissue injuries from pencilling of the armour and the shirt worn under the armour. The wounds had embedded fabric debris which would require surgery to remove resulting in increased recovery time over injuries usually seen in anterior torso BABT impacts, which are typically haematoma and fractured ribs. The shot with the deepest soft tissue wound (41 mm) also resulted in a fractured spinous process. Shots were also fired at the posterior and anterior rib area of the pig barrel, for comparison to the spine. Similar wounds were seen on the shots to the posterior rib area while shallower, smaller wounds were seen on the anterior and one anterior rib shot resulted in a single, un-displaced rib fracture. The anatomical differences between pigs and humans would most likely mean that injury to a human from these impacts would be more serious.

J Trauma Acute Care Surg. 2018 Jul;85(1S Suppl 2):S112-S121

# The effect of prehospital transport time, injury severity, and blood transfusion on survival of US military casualties in Iraq.

Kotwal R, Scott L, Janak J, Tarpey B, Howard J, Mazuchowski E, Butler F, Shackelford S, Gurney J, Stockinger Z

BACKGROUND: Reducing time from injury to care can optimize trauma patient outcomes. A previous study of prehospital transport of US military casualties during the Afghanistan conflict demonstrated the importance of time and treatment capability for combat casualty survival.

METHODS: A retrospective descriptive analysis was conducted to analyze battlefield data collected on US military combat casualties during the Iraq conflict from March 19, 2003, to August 31, 2010. All casualties were analyzed by mortality outcome (killed in action, died of wounds, case fatality rate) and compared with Afghanistan conflict. Detailed data for those who underwent prehospital transport were analyzed for effects of transport time, injury severity, and blood transfusion on survival.

RESULTS: For the total population, percent killed in action (16.6% vs. 11.1%), percent died of wounds (5.9% vs. 4.3%), and case fatality rate (10.0 vs. 8.6) were higher for Iraq versus Afghanistan (p < 0.001). Among 1,692 casualties (mean New Injury Severity Score, 22.5; mortality, 17.6%) with detailed data, the injury mechanism included 77.7% from explosions and 22.1% from gunshot wounds. For prehospital transport, 67.6% of casualties were transported within 60 minutes, and 32.4% of casualties were transported in greater than 60 minutes. Although 97.0% of deaths occurred in critical casualties (New Injury Severity Score, 25-75), 52.7% of critical casualties survived. Critical casualties were transported more rapidly (p < 0.01) and more frequently within 60 minutes (p < 0.01) than other casualties. Critical casualties had lower mortality when blood was received (p < 0.01). Among critical casualties, blood transfusion was associated with survival irrespective of transport time within or greater than 60 minutes (p < 0.01).

CONCLUSION: Although data were limited, early blood transfusion was associated with battlefield survival in Iraq as it was in Afghanistan.

LEVEL OF EVIDENCE: Performance improvement and epidemiological, level IV.

J Trauma Acute Care Surg. 2018 Sep;85(3):603-612

# A US military role 2 forward surgical team database study of combat mortality in Afghanistan.

Kotwal R, Staudt A, Mazuchowski E, Gurney J, Shackelford S, Butler F, Stockinger Z, Holcomb J, Nessen S, Mann-Salinas E

BACKGROUND: Timely and optimal care can reduce mortality among critically injured combat casualties. US military Role 2 surgical teams were deployed to forward positions in Afghanistan on behalf of the battlefield trauma system. They received prehospital casualties, provided early damage control resuscitation and surgery, and rapidly transferred casualties to Role 3 hospitals for definitive care. A database was developed to capture Role 2 data.

METHODS: A retrospective review and descriptive analysis were conducted of battle-injured casualties transported to US Role 2 surgical facilities in Afghanistan from February 2008 to September 2014. Casualties were analyzed by mortality status and location of death (pretransport, intratransport, or posttransport), military affiliation, transport time, injury type and mechanism, combat mortality index-prehospital (CMI-PH), and documented prehospital treatment.

RESULTS: Of 9,557 casualties (median age, 25.0 years; male, 97.4%), most (95.1%) survived to transfer from Role 2 facility care. Military affiliation included US coalition forces (37.4%), Afghanistan National Security Forces (23.8%), civilian/other forces (21.3%), Afghanistan National Police (13.5%), and non-US coalition forces (4.0%). Mortality differed by military affiliation (p < 0.001). Among fatalities, most were Afghanistan National Security Forces (30.5%) civilian/other forces (26.0%), or US coalition forces (25.2%). Of those categorized by CMI-PH, 40.0% of critical, 11.2% of severe, 0.8% of moderate, and less than 0.1% of mild casualties died. Most fatalities with CMI-PH were categorized as critical (66.3%) or severe (25.9%), whereas most who lived were mild (56.9%) or moderate (25.4%). Of all fatalities, 14.0% died prehospital (pretransport, 5.8%; intratransport, 8.2%), and 86.0% died at a Role 2 facility (posttransport). Of fatalities with documented transport times (median, 53.0 minutes), most (61.7%) were evacuated within 60 minutes.

CONCLUSIONS: Role 2 surgical team care has been an important early component of the battlefield trauma system in Afghanistan. Combat casualty care must be documented, collected, and analyzed for outcomes and trends to improve performance.

LEVEL OF EVIDENCE: Therapeutic/Care Management, level IV.

Wilderness Environ Med. 2018 Jun;29(2):266-274

# Challenges of military health service support in mountain warfare.

Lechner R, Küpper T, Tannheimer M

INTRODUCTION: History is full of examples of the influence of the mountain environment on warfare. The aim of this article is to identify the main environmental hazards and summarize countermeasures to mitigate the impact of this unique environment.

METHODS: A selective PubMed and Internet search was conducted. Additionally, we searched bibliographies for useful supplemental literature and included the recommendations of the leading mountain medicine and wilderness medicine societies.

RESULTS: A definition of mountain warfare mainly derived from environmental influences on body functions is introduced to help identify the main environmental hazards. Cold, rugged terrain, hypoxic exposure, and often a combination and mutual aggravation of these factors are the most important environmental factors of mountain environment. Underestimating this environmental influence has decreased combat strength and caused thousands of casualties during past conflicts. Some marked differences between military and civilian mountaineering further complicate mission planning and operational sustainability.

CONCLUSIONS: To overcome the restrictions of mountain environments, proper planning and preparation, including sustained mountain mobility training, in-depth mountain medicine training with a special emphasize on prolonged field care, knowledge of acclimatization strategies, adapted time calculations, mountain-specific equipment, air rescue strategies and makeshift evacuation strategies, and thorough personnel selection, are vital to guarantee the best possible medical support. The specifics of managing risks in mountain environments are also critical for civilian rescue missions and humanitarian aid.

J Trauma Acute Care Surg. 2018 Jul;85(1S Suppl 2):S4-S12

# Unrealized potential of the US Military Battlefield Trauma System: DOW rate is higher in Iraq and Afghanistan that in Vietnam, but CFR and KIA rate are lower.

Nessen S, Gurney J, Rasmussen T, Cap A, Mann-Salinas E, Le T, Shackelford S, Remick K, Akers K, Eastridge B, Jenkins D, Stockinger Z, Murray C, Gross K, Seery J, Mabry R, Holcomb J

J Vasc Surg. 2018 Jun 11. pii: S0741-5214(18)30997-2. doi: 10.1016/j.jvs.2018.04.038. [Epub ahead of print]

# A contemporary, 7-year analysis of vascular injury from the war in Afghanistan.

Patel J, White J, White P, Rich N, Rasmussen T

OBJECTIVE: Vascular injury is a leading cause of death and disability in military and civilian trauma. Although a previous interim study defined the distribution of vascular injury during the wars in Iraq and Afghanistan, a contemporary epidemiologic assessment has not been performed. The objective of this study was to provide a current analysis of vascular injury during the final 7 years of the war in Afghanistan, including characterization of anatomic injury patterns, mechanisms of injury, and methods of acute management.

METHODS: The Department of Defense Trauma Registry was analyzed to identify U.S. military service members who sustained a battle-related vascular injury and survived to be treated at a surgical facility in Afghanistan between January 1, 2009, and December 31, 2015. All battle-related injuries (nonreturn to duty) were used as a denominator to establish the injury rate. Mechanism and anatomic distribution of injury as well as the acute management strategies of revascularization, ligation, and use of endovascular techniques were defined.

RESULTS: Of 3900 service members who sustained a battle-related injury, 685 patients (17.6%) had 1105 vascular injuries (1.6 vascular injuries per patient). Extremity trauma accounted for 72% (n = 796) of vascular injuries, followed by the torso (17%; n = 188) and cervical (11%; n = 118) regions. Lower extremity vascular injury was the most prevalent anatomic location (45%; 501/1105). Explosion with fragment penetration accounted for 70% (477/685) of injuries, whereas gunshot wounds accounted for 30% (205/685). Open repair was performed in 559 cases (57%; 554/981), whereas ligation was the initial management strategy in 40% (395/981) of cases. In addition, 374 diagnostic endovascular procedures were completed, 27 therapeutic endovascular interventions to include stent placement and angioplasty were performed and 55 inferior vena cava filters were placed. Mortality of the vascular injury cohort was 5%.

CONCLUSIONS: The rate of vascular injury in modern combat is higher than that reported in previous wars. Open reconstruction is performed in half of cases, although ligation is an important damage control option, especially for minor or distal vessel injuries. Angiographic techniques are increasingly being used and documented within wartime registries more than ever. Proficiency with open and endovascular methods of vascular injury management remains a critical need for the U.S. military and will require partnership with civilian institutions to attain and maintain.

Trauma Surg Acute Care Open. 2018 Jun 27;3(1):e000193. doi:10.1136/tsaco-2018-000193. eCollection 2018.

# Launch of the National Trauma Research Repository coincides with new data sharing requirements.

Price M, Bixby P, Phillips M, Beilman G, Bulger E, Davis M, McAuliffe M, Rasmussen T, Salinas J, Smith S, Spott M, Weireter L, Jenkins D

Previous analyses of research data have shown that many trauma studies cannot be replicated or validated due to a variety of factors, including lack of access to study data, lack of access to protocol information, and inability to replicate procedures used in the study. New data sharing rules for federally funded studies have been put in place to address factors associated with this issue.

To address these new data sharing requirements, beginning this month, investigators conducting research on trauma and critical care will be able to maximize the utility of the data they produce with the launch of the National Trauma Research Repository (NTRR). The system was developed as a resource to support new and emerging data sharing needs within the trauma research community and is envisioned to be a key piece of the national trauma research infrastructure. It is funded by the Department of Defense (DoD) and developed by the National Trauma Institute (NTI) to promote collaboration, accelerate research, and advance knowledge on the treatment of trauma. When it becomes fully functional, the NTRR will be a comprehensive repository offering thousands of data points from hundreds of studies, enabling investigators to query across studies for their own research objectives.

Am J Emerg Med. 2018 May 2. pii: S0735-6757(18)30363-2. doi: 10.1016/j.ajem.2018.04.068. [Epub ahead of print]

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

Schauer S, Naylor J, Oliver J, Maddry J, April M

BACKGROUND: During the past 17 years of conflict the deployed US military health care system has found new and innovative ways to reduce combat mortality down to the lowest case fatality rate in US history. There is currently a data dearth of emergency department (ED) care delivered in this setting. We seek to describe ED interventions in this setting.

METHODS: We used a series of ED procedure codes to identify subjects within the Department of Defense Trauma Registry from January 2007 to August 2016.

RESULTS: During this time, 28,222 met inclusion criteria. The median age of causalities in this dataset was 25 years and most (96.9%) were male, US military (41.3%), and part of Operation Enduring Freedom (66.9%). The majority survived to hospital discharge (95.5%). Most subjects sustained injuries by explosives (55.3%) and gunshot wound (GSW). The majority of subjects had an injury severity score that was considered minor (74.1%), while the preponderance of critically injured casualties sustained injuries by explosive (0.7%). Based on AIS, the most frequently seriously injured body region was the extremities (23.9%). The bulk of administered blood products were packed red blood cells (PRBC, 26.4%). Endotracheal intubation was the most commonly performed critical procedure (11.9%). X-ray (79.9%) was the most frequently performed imaging study.

CONCLUSIONS: US military personnel comprised the largest proportion of combat casualties and most were injured by explosive. Within this dataset, ED providers most frequently performed endotracheal intubation, administered blood products, and obtained diagnostic imaging studies.