OpMed Journal Watch December 2019

Photo by Aaron Burden
Photo by Aaron Burden

Outcomes of Casualties Without Airway Trauma Undergoing Prehospital Airway Interventions: A Department of Defense Trauma Registry Study

Steven G Schauer, DO, MS, Jason F Naylor, PA-C, Joseph K Maddry, MD, et al. Military Medicine, Dec 2019, doi: 10.1093/milmed/usz349

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. However, casualties may require airway interventions for other indications (e.g., depressed mental status). We describe casualties undergoing airway intervention in the prehospital, combat setting without apparent upper airway trauma. In this subgroup analysis of casualties without apparent upper airway trauma, survival rates were lower when compared to our previous report. Higher quality data are necessary to better understand the resuscitation needs of this critically ill subset of combat casualties.

Safety profile and impact of low-titer group O whole blood for emergency use in trauma.

Williams J, Merutka N, Meyer D, et al. J Trauma Acute Care Surg. 2020 Jan;88(1):87-93. doi: 10.1097/TA.0000000000002498.

Following US military implementation of a cold-stored whole blood program, several US trauma centers have begun incorporating uncrossmatched, group O cold-stored whole blood into civilian trauma resuscitation. We set out to evaluate the safety profile, transfusion reactions events, and impact of low-titer group O whole blood (LTO-WB) at our center. One hundred ninety-eight patients received LTO-WB and 152 patients received COMP. There were no differences in age, sex, or mechanism. The LTO-WB patients had higher chest Abbreviated Injury Scale scores (median, 3 vs. 2; p = 0.027), as well as worse arrival base excess (median, -7 vs. -5; p = 0.014) and lactate (5.1 vs. 3.5; p < 0.001). The LTO-WB patients received less post-ED blood products than the COMP patients (median, 0 vs. 3; p = 0.001). There was no difference in survival (LTO-WB, 73%; COMP, 74%; p = 0.805). There were only two suspected transfusion reactions, both in the COMP group (p = 0.061). There was no difference in hemolysis panel values. Controlling for age, severity of injury, and prehospital physiology, LTO-WB was associated with a 53% reduction in post-ED blood product transfusion (odds ratio, 0.47; 0.23-0.94 95% CI; p = 0.033) and two-fold increase in likelihood of survival (odds ratio, 2.19; 1.01-4.76 95% CI; p = 0.047).

Low-titer group O whole blood has similar evidence of laboratory hemolysis, similar transfusion reaction rates, and is associated with a reduction in post-ED transfusions and increase likelihood of survival.

Use of ketamine for prehospital pain control on the battlefield

de Rocquigny, Gaël MD; Dubecq, Christophe MD; Martinez, Thibault MD et al. Journal of Trauma and Acute Care Surgery: January 2020 – Volume 88 – Issue 1 – p 180-185doi: 10.1097/TA.0000000000002522

Intravenous ketamine is commonly used for pain management in the civilian prehospital setting. Several studies have evaluated its effectiveness in the military setting. To date, there has been no report reviewing the published data on the use of ketamine in this context. The objective of this systematic review was to analyze the content and quality of published data on the use of ketamine for prehospital pain management in military trauma. Ketamine use rose from 3.9% during the period preceding its addition to the Tactical Combat Casualty Care guidelines in 2012 to 19.8% thereafter. It was the most common analgesic administered (up to 52% of casualties) in one of the studies. Ketamine was more likely given during tactical medical evacuation when no analgesic was provided at the point of injury. The median total intravenous dose was 50 mg. Pain intensity decreased from moderate or severe to mild or none, sometimes after only one dose. In one study, ketamine administration during tactical evacuation was associated with increased systolic blood pressure as opposed to morphine. Incoherent speech, extremity movements, and hallucinations were the main adverse events reported.

Published data on ketamine use in military trauma are rare and heterogeneous. Though, all studies tend to strengthen the belief in the efficacy and safety of ketamine when given at 50-mg to 100-mg intravenous for prehospital analgesia in combat casualties.

Getting Our Money’s Worth From Clinical Care Studies of Prehospital Trauma Care

Todd E. Rasmussen, MD; Laura R. Brosch, RN, PhD. JAMA Surg. Published online December 18, 2019. doi:10.1001/jamasurg.2019.5086

Getting the most information in the most ethical manner from investments in medical research is a primary goal for all who manage this type of financial appropriation, whether at the National Institutes of Health, the Department of Defense, or elsewhere. Clinical studies of prehospital trauma care, such as that published by Pusateri et al1 in this issue of JAMA Surgery, are particularly challenging (and expensive) because they require enrollment of patients with a waiver of informed consent and data that are difficult to collect and analyze. Several important features of the study by Pusateri et al1 should assure US taxpayers that, in this case, they got their money’s worth.

Epidemiological and Accounting Analysis of Ground Ambulance Whole Blood Transfusion

Prehospital and Disaster Medicine Volume 35Issue 1 February 2020 , pp. 98-103 DOI: https://doi.org/10.1017/S1049023X1900517X

In October 2017, the American Association of Blood Bankers (AABB; Bethesda, Maryland USA) approved a petition to allow low-titer group O whole blood as a standard product without the need for a waiver. Around that time, a few Texas, USA-based Emergency Medical Services (EMS) systems incorporated whole blood into their ground ambulances. The purpose of this project was to describe the epidemiology of ground ambulance patients that received a prehospital whole blood transfusion. The secondary aim of this project was to report an accounting analysis of these ground ambulance prehospital whole blood programs.

Of 58 consecutive prehospital whole blood administrations, the team included all 58 cases. Hemorrhagic shock from a non-traumatic etiology accounted for 46.5% (95% CI, 34.3%-59.2%) of prehospital whole blood recipients. In the non-traumatic hemorrhagic shock cohort, gastrointestinal hemorrhage was the underlying etiology of hemorrhagic shock in 66.7% (95% CI, 47.8%-81.4%) of prehospital whole blood transfusion recipients. The projected average cost to save a life in Year 10 was US$5,136.51 for the combined cohort, US$4,512.69 for HCESD 48, and US$5,243.72 for SAFD EMS.

This retrospective analysis of ground ambulance patients that receive prehospital whole blood transfusion found that non-traumatic etiology accounted for 46.5% (95% CI, 34.3%-59.2%) of prehospital whole blood recipients. Additionally, the accounting analysis suggests that by Year 10 of a ground ambulance whole blood transfusion program, the average cost to save a life will be approximately US$5,136.51.

Serious Altitude Illness at the South Pole

Rose, John S.; Law, Jennifer; Scheuring, Richard; Ramage, Matthew H.; McKeith, James J. Aerospace Medicine and Human Performance. 91(1) pp. 46-50(5) doi: 10.3357/AMHP.5467.2020

Gradual ascent is impractical for personnel deploying to the South Pole due to logistical challenges. Prevention of altitude illness relies on prophylactic medications such as acetazolamide and behavioral modifications including hydration and avoidance of overexertion. We present three recent cases of altitude illness that occurred in previously healthy individuals at the South Pole. These patients illustrate that altitude illness may develop despite medical screening, participant education, and availability of prophylactic medications based on published guidelines. These cases could be attributed to noncompliance and misinformation, bringing to light some of the challenges with managing more diverse populations that deploy to remote environments.

Association of Prehospital Plasma Transfusion With Survival in Trauma Patients With Hemorrhagic Shock When Transport Times Are Longer Than 20 Minutes

Anthony E. Pusateri, PhD; Ernest E. Moore, MD; Hunter B. Moore, MD, PhD; et al. JAMA Surg. Published online Dec, 2019. doi:10.1001/jamasurg.2019.5085

Question  Is prehospital plasma administration more beneficial when patient transport times are longer? Findings  This post hoc analysis was performed using harmonized data from 2 randomized clinical trials, Control of Major Bleeding After Trauma and Prehospital Air Medical Plasma, which included 626 patients with trauma and hemorrhagic shock. Patients who received prehospital plasma transfusion had significantly reduced 28-day mortality compared with standard care when prehospital transport times were longer than 20 minutes. Meaning  Prehospital plasma administration is associated with reduced mortality in patients with trauma and significant hemorrhage when transport times are prolonged.

Retention of Tourniquet Application Skills Following Participation in a Bleeding Control Course

Steve Weinman MSc, RN. Journal of Emergency Nursing. Dec 2019. doi: 10.1016/j.jen.2019.10.020

The American College of Surgeons’ Stop the Bleed program has trained more than 1 million individuals to recognize and treat external hemorrhage. Central to this training is tourniquet application. No published studies review the retention of this skill after initial class participation. At 6 months, 39% of participants were unable to successfully apply a tourniquet, and 26% were unable to control life-threatening bleeding. This study demonstrates that refresher training is needed within 6 months of initial training.

Acute high-altitude pathologies and their treatment

Alexander I. R. Jackson, Andrew F. Cumpstey, Michael P. W. Grocott. Current Opinion in Endocrine and Metabolic Research. doi: 10.1016/j.coemr.2019.12.001

Ascent to high altitude triggers a wide range of physiological changes. However, ascent is also associated with three acute pathologies: acute mountain sickness, high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). Awareness and understanding of these conditions allows measures to be taken to reduce the risk of them developing through careful planning and, where appropriate, pharmacological prophylaxis. Both HACE and HAPE are life threatening, necessitating prompt diagnosis and management. Acute mountain sickness, although usually benign, may progress, to HACE or HAPE, if not managed appropriately. This review examines each pathology providing options for risk reduction, diagnosis and management, as well as considering comorbidity at altitude, drawing upon recent advances and consensus guidelines in the field.

Forward Surgical Team Procedural Burden and Non-operative Interventions by the U.S. Military Trauma System in Afghanistan, 2008–2014

Amanda M Staudt, PhD, Mithun R Suresh, MD, Jennifer M Gurney, MC, USA, et al. Military Medicine, 2019 Dec, doi:10.1093/milmed/usz402

No published study has reported non-surgical interventions performed by forward surgical teams, and there are no current surgical benchmarks for forward surgical teams. The objective of the study was to describe operative procedures and non-operative interventions received by battlefield casualties and determine the operative procedural burden on the trauma system.

The study population was comprised of 10,992 casualties, primarily male (97.8%), with a median age interquartile range of 25.0 (22.0–30.0). Affiliations were non-U.S. military (40.0%), U.S. military (35.1%), and others (25.0%). Injuries were penetrating (65.2%), blunt (32.8), and burns (2.0%). Casualties included 4.4% who died and 14.9% who lived but had notable morbidity findings. After ranking by contribution to trauma system morbidity and mortality burden, the top 10 of 32 procedure groups accounted for 74.4% of operative care, 77.9% of mortality, and 73.1% of unexpected morbidity findings. These procedure groups included laparotomy, vascular procedures, thoracotomy, debridement, lower and upper gastrointestinal procedures, amputation, and therapeutic procedures on muscles and upper and lower extremity bones. Most common non-operative interventions included X-ray, ultrasound, wound care, catheterization, and intubation.

Forward surgical team training and performance improvement metrics should focus on optimizing commonly performed operative procedures and non-operative interventions. Operative procedures that were commonly performed, and those associated with higher rates of morbidity and mortality, can set surgical benchmarks and outline training and skillsets needed by forward surgical teams.

Blast concussion and posttraumatic stress as predictors of postcombat neuropsychological functioning in OEF/OIF/OND veterans.

Nelson, Nathaniel W. Disner, Seth G. Anderson, Carolyn R. et al. Neuropsychology. 2019 Dec; 34(1), 116–126. doi: 10.1037/neu0000594

Many combat veterans exhibit cognitive limitations of uncertain origin. In this study, we examined factors that predict cognitive functioning by considering effects of blast-related concussion (BRC), non-blast-related concussion (NBRC), and posttraumatic stress disorder (PTSD) symptoms. Analyses specifically tested whether (a) BRC and NBRC were distinct in their prediction of cognitive performance; (b) a dose-response relationship existed between recurrent concussion (BRC and NBRC) and cognitive impairment; and (c) PTSD symptoms mediated the relationship between BRC and cognitive performance. A structural equation model (SEM) suggested that BRC and NBRC were not distinct in their prediction of cognitive performance, and there was no evidence that recurrent concussion (blast or nonblast) was directly associated with cognitive performance. BRC was significantly associated with PTSD symptoms (r = .24), PTSD symptoms were significantly associated with cognitive performance in the SEM (r = −.27), and PTSD symptoms significantly mediated the link between BRC and cognitive performance (p = .03). 

These results suggest that concussion history fails to directly contribute to cognitive performance, regardless of mechanism (blast or nonblast) and recurrence. BRC is nonetheless unique in its contribution to PTSD and PTSD-related cognitive deficits. Results support interventions specific to PTSD management in the interest of promoting neuropsychological functioning among war veterans. 

Compassion fatigue in healthcare providers: A systematic review and meta-analysis

Nicola Cavanagh, Grayson Cockett, Christina Heinrich, et al. Nursing Ethics. 2019 Dec. https://doi.org/10.1177/0969733019889400

Compassion fatigue is recognized as impacting the health and effectiveness of healthcare providers, and consequently, patient care. Compassion fatigue is distinct from “burnout.” Reliable measurement tools, such as the Professional Quality of Life scale, have been developed to measure the prevalence, and predict risk of compassion fatigue. This study reviews the prevalence of compassion fatigue among healthcare practitioners, and relationships to demographic variables. Compassion fatigue exists across diverse practitioner groups. Prevalence is highly variable, and its relationship with demographic, personal, and/or professional variables is inconsistent. Questions are raised about how to mitigate compassion fatigue.

Global surgery for paediatric casualties in armed conflict

Frederike J. C. Haverkamp, Lisanne van GennipMåns MuhrbeckHarald VeenAndreas WladisEdward C. T. H. Tan. World Journal of Emergency Surgery. 2019 Dec. doi: 10.1186/s13017-019-0275-9

Understanding injury patterns specific for paediatric casualties of armed conflict is essential to facilitate preparations by organizations that provide medical care in conflict areas. The aim of this retrospective cohort study is to identify injury patterns and treatment requirements that are specific for paediatric patients in conflict zones. When compared with adult patients, children were more frequently seen with fragment injuries, burns and mine injuries; they had injuries to multiple body regions more often and had higher in-hospital mortality rates. Children more often sustained injuries to multiple body regions and had higher in-hospital mortality than adults. These findings could have implications for how the ICRC and other organizations prepare personnel and structure logistics to meet the treatment needs of paediatric victims of armed conflicts.

Identifying bladder rupture following traumatic pelvic fracture: A machine learning approach

Alexandria M. Hertz, Nicholas M. Hertz, Niels V. Johnsen. Injury. 2019 Dec; 51(2):334-339. doi: 10.1016/j.injury.2019.12.009

Bladder rupture following blunt pelvic trauma is rare though can have significant sequelae. We sought to determine whether machine learning could help predict the presence of bladder injury using certain factors at the time of presentation of blunt pelvic trauma. Of the 3063 eligible pelvic fracture patients identified, 208 (6.8%) had concomitant bladder ruptures. 

Machine learning algorithms can be used to help predict with a high level of accuracy the presence of bladder rupture with blunt pelvic trauma using readily available information at the time of presentation. This has the potential to improve selection of patients for additional imaging, while also more appropriately allocating hospital resources and reducing patient risks.

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

Andrew D. Fisher MPAS, PA-C, LP, Michael D. April MD, DPhil, Steven G. Schauer DO, MS. The American Journal of Emergency Medicine. 2019 Dec. doi: 10.1016/j.ajem.2019.11.050

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. 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.

Acetazolamide does not alter endurance exercise performance at 3500 m altitude

Karleigh E. Bradbury, Beau R. Yurkevicius, Katherine M. Mitchell, et al. Journal of Applied Physiology. 2019 Dec. doi: 10.1152/japplphysiol.00655.2019

Acetazolamide (AZ) is a medication commonly used to prevent acute mountain sickness (AMS) during rapid ascent to high altitude. However, it is unclear whether AZ use impairs exercise performance; previous literature regarding this topic is equivocal. The purpose of this study was to evaluate the impact of AZ on time trial (TT) performance during a 30-hr exposure to hypobaric hypoxia equivalent to 3500 m altitude. The incidence of AMS decreased from 40% with placebo to 0% with AZ. Our results suggest that AZ (500 mg/day) does not negatively impact endurance exercise performance at 3500 m.

Avalanche airbag post-burial active deflation — The ability to create an air pocket to delay asphyxiation and prolong survival

Scott E. McIntosh, Colin E. Little, Thomas D. Seibert, Natalya E.Polukoff, Colin K.Grissom. Resuscitation. Volume 146, January 2020, Pages 155-160

The primary purpose of an avalanche airbag is to prevent burial during an avalanche. Approximately twenty percent of avalanche victims deploying airbags become critically buried, however. One avalanche airbag actively deflates three minutes after deployment, potentially creating an air pocket. Our objective was to evaluate this air pocket and its potential to prevent asphyxiation. The avalanche airbag under study creates an air pocket that appears to delay asphyxia, which could allow extra time for rescue and improve overall survival of avalanche victims.

Hypothermia and Cold Weather Injuries

NICHOLAS A. RATHJEN, DO, and S. DAVID SHAHBODAGHI, MD, MPH. Am Fam Physician. 2019 Dec 1;100(11):680-686. (https://www.aafp.org/afp/2019/1201/p680.html)

Hypothermia, frostbite, and nonfreezing cold injuries predominantly affect older adults, homeless or intoxicated people, adventurers, and military personnel. Prevention begins with clothing that is clean, layered, and loose to promote circulation. Base layers made of moisture-wicking materials are favored over wool or cotton. Wool or fleece garments are ideal for middle layers, whereas outer layers should repel moisture. Hypothermia occurs when core body temperature drops below 95°F and can be staged by clinical symptoms when core temperature measurement is unavailable. Initial treatment includes external and internal rewarming. Warmed normal saline is favored over lactated Ringer solution. Frostbite is a freezing injury that usually affects the extremities. After rapid rewarming, prognosis is best determined with technetium 99mTc pyrophosphate scintigraphy or magnetic resonance angiography. Initial treatment includes protecting tissue from further trauma, preventing refreezing, and avoiding dry heat sources. Ideally, patients should be transported to facilities where rapid rewarming, imaging, and thrombolytic treatment are available. Tissue plasminogen activator significantly decreases amputation rates for severe injuries if started within 24 hours of rewarming. Immersion foot occurs during damp nonfreezing conditions. Rapid rewarming should be avoided, and amitriptyline should be considered for pain control.

An expandable one-way-valve device for chest wound treatment: Evaluation of open pneumothorax in a canine model

Weijin Yanga, Youxu Zhoub, Jianshen Qiu, et al. Asian Journal of Surgery. doi: 10.1016/j.asjsur.2019.10.013

Thoracic injuries commonly occur after blunt or penetrating trauma, leading to a blowing wound. For thoracic damage control in emergency, we evaluated a novel chest wound treatment device manufactured using expandable material with a one-way valve, and compared it with closed thoracic drainage for first-line treatment of traumatic pneumothorax in a canine model.

After a 24-h experimental period, all animals survived. The control group recovered more quickly than the experimental group at 30 min post-trauma. However, the indices were close to normal 120 min after the test device was inserted. During the puncture, chest-wall hemorrhage was stopped by using the device, whereas the control group experienced continual errhysis. The lung had almost re-expanded at the end of the experiment in both groups. The effect of pulmonary re-expansion in the control group was better than that in the experimental group at 120 min. The novel expandable one-way valve device is a safe and useful tool for the treatment of open chest trauma in emergency based on our animal experiment.

The US military experience with THAM

Gonzalo de Taboada, Mohamad A. Umara, Monica L. Casmaera, Lorne H. Blackbourne, Steven G. Schauer. The American Journal of Emergency Medicine. 2019 Dec. doi: 10.1016/j.ajem.2019.11.026

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. 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 patients evacuated by a civilian physician-staffed helicopter from a military base

Youichi Yanagawa, Hiroki Nagasawa, et al. J Rural Med. 2019 Nov; 14(2): 231–235. doi: 10.2185/jrm.3012

We herein report our analysis of patients evacuated by a physician-staffed helicopter (doctor helicopter; DH) from a Japan Self Defense Force (JSDF) base. From March 2004 to November 2018, a medical chart review was retrospectively performed for all patients who were transported by a DH from the temporary heliport at the JSDF Fuji base. Patients transported by DHs in the After-2013 group tended to be in more severe conditions than those transported in the Before-2013 group. This might be due to the fact that over time, the fire department, or JSDF, began to appreciate the useful role played by the DH in life-saving management.

Tracking Training Load and Its Implementation in Tactical Populations

Maupin, Danny DPhty, ATC; Schram, Ben PhD, DPhty; Orr, Robin PhD. Strength and Conditioning Journal: December 2019 – Volume 41 – Issue 6 – p 1-11 doi: 10.1519/SSC.0000000000000492

Tactical populations often participate in demanding physical training and perform strenuous workplace tasks, increasing injury risk. Mitigating injury risk is vital for maintaining trained personnel and should be a focus for tactical populations. One such method, tracking training load, has not been studied in-depth in tactical populations, despite documented effectiveness in elite sport. Most injuries to tactical personnel are overuse in nature and therefore may be prevented by optimizing training load. Although the methods used in elite sport may not be directly transferrable to tactical environments, they may be used to inform injury mitigation strategies in tactical populations.

Impact of rewarming rate on the mortality of patients with accidental hypothermia: analysis of data from the J-Point registry

Tasuku Matsuyama, et al. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine. December 2019. doi: 10.1186/s13049-019-0684-5

Accidental hypothermia (AH) is defined as an involuntary decrease in core body temperature to < 35 °C. The management of AH has been progressing over the last few decades, and numerous techniques for rewarming have been validated. However, little is known about the association between rewarming rate (RR) and mortality in patients with AH. This study showed that slower RR is independently associated with in-hospital mortality.

Travel medicine, coca and cocaine: demystifying and rehabilitating Erythroxylum – a comprehensive review

Irmgard Bauer. Tropical Diseases, Travel Medicine and Vaccines. December 2019. doi: 10.1186/s40794-019-0095-7

Few travel health measures are as controversial as the use of coca leaves at high altitude; yet, there appears widespread ignorance among health professionals and the general public about coca, its origins as well as its interesting and often flamboyant history. Equally, the cultural and traditional significance to Andean people is not recognised. The coca leaves contain many alkaloids, one of which, cocaine, has gained notoriety as a narcotic, leading to the mistaken idea that coca equals cocaine. This article contrasts coca with cocaine in an attempt to explain the differences but also the reasons for this widespread misconception. By its very nature, there may never be scientific ‘proof’ that coca leaves do or do not work for travellers at altitude, but at least a solid knowledge of coca, and how it differs from cocaine, provides a platform for informed opinions and appropriate critical views on the current confusing and contradictory legal situation.

Simulated Aeromedical Evacuation in a Polytrauma Rat Model

Françoise Arnaud; Georgina Pappas; Eric Maudlin-Jeronimo; Carl Goforth. Aerospace Medicine and Human Performance. December 2019, Volume 90, Issue 12, pp 1016-1025. doi: 10.3357/AMHP.5477.2019

Hemorrhage and traumatic brain injury can be lethal if left unattended. The transportation of severely wounded combat casualties from the battlefield to higher level of care via aeromedical evacuation (AE) may result in unintended complications. This could become a serious concern at the time of evacuation of mass casualties or for prolonged field care scenarios with limited resources.

Survival was 100% in control-uninjured animals, 83% in injured animals under normobaria, and significantly reduced to 50% under hypobaria. This AE setting resulted in significantly lower hemodynamics, thermoregulation, and oxygenation parameters in the animals under hypobaria than those under normobaria. The initial lower mean arterial pressure (MAP) with the reduced oxygen level before AE were critical factors for the survival of injured animals. We observed a general increase of white blood cells and platelet ability to aggregate at t4 in all experimental groups. Physiological parameters were affected during aeromedical evacuation in all groups. This was worsened for injured animals with MAP less than 60 mmHg associated with low SpO2 in a simulated aeromedical evacuation. This represented a high risk of mortality for severely polytraumatized animals.

Combat Casualty Care Statistics as Outcome Measures for Medical Treatment on the Battlefield: A Review and Reconsideration of the Data

Shawn C. Nessen, Tuan D. Le, Jennifer M. Gurney. Current Trauma Reports. December 2019, Volume 5, Issue 4, pp 187–194. doi: 10.1007/s40719-019-00177-3

This review focuses on the use of the case fatality rate (CFR), the killed in action percentage (%KIA) and died of wounds (%DOW) as battlefield medical outcome measures and reports the current statistical data for recent conflicts. Further, the review defines each statistic, and identifies their usefulness and limitations in medical research.

Recent Findings. The CFR, %KIA, and %DOW have been used by many authors since the beginning of the conflicts in Afghanistan and Iraq in 2001. However, these statistics are primarily derived from administrative databases maintained by the Defense Casualty Analysis System, and their primary purpose is not to evaluate the effectiveness of medical treatment. We believe both the magnitude of the improvements in CFR and %KIA and impact of medical treatment on these statistics have been in some cases overstated. Summary. Battlefield lethality is significantly impacted by non-medical factors. Some medical researchers, likely unknowingly, continue to use these statistics, especially the CFR, without taking all battlefield confounders into account. The Department of Defense Trauma Registry provides opportunity for improved data collection, performance improvement, and standardization of the combat casualty care statistics thereby allowing for meaningful comparisons and a better understanding of battlefield trauma care.


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