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Artificial Blood Development Implications for Military Medicine

Fall 2023

Melanson V, Hershfield J, Deegan MK, Cho H, Perinon D, Bateman SL, Barnhill JC. 23(3). 63 - 69. (Journal Article)

Abstract

Massive hemorrhaging remains the most common cause of preventable battlefield deaths. Blood used for trauma care requires a robust donation network, capacity for long-term storage, and extensive and accurate testing. Bioengineering technologies could offer a remedy to these constraints in the form of blood substitutes-fluids that could be transfused into patients to provide oxygen, carry away waste, and aid in coagulation-that would be used in prolonged casualty care and in far-forward settings, overcoming the obstacles of distance and time. The different molecular properties of red blood cells (RBCs), blood substitutes, and platelet replacements contribute to their respective utilities, and each type is currently represented in ongoing clinical trials. Hemoglobin oxygen carriers (HBOCs) are the most advanced RBC replacements, many of which are currently being evaluated in clinical trials in the United States and other countries. Despite recent advancements, challenges remaining in the development of blood alternatives include stability, oxygen capacity, and compatibility. The continued research and investment in new technologies has the potential to significantly benefit the treatment of life-threatening emergency injuries, both on the battlefield and in the civilian sector. In this review, we discuss military blood-management practices and military-specific uses of individual blood components, as well as describe and analyze several artificial blood products that could be options for future battlefield use.

Keywords: artificial blood; blood substitutes; red blood cell substitutes; platelet replacements; biomanufacturing

Pain Control and Point-of-Care Ultrasound: An Approach to Rib Fractures for the Austere Provider

Fall 2023

Snyder R, Brillhart DB. 23(3). 70 - 73. (Journal Article)

Abstract

Rib fractures are common injuries that cause significant discomfort and can lead to severe pulmonary complications. Rib injury most often results from high-velocity traumatic mechanisms, while rarely representing underlying metastatic disease or secondary injury due to pulmonary illness. Because most rib fractures are caused by obvious trauma, algorithms are focused on treatment rather than investigating the exact mechanism of rib fractures. Chest radiographs are often the initial imaging performed but have proven to be unreliable in identification of rib fracture. Computed tomography (CT) is a diagnostic option as it is more sensitive and specific than simple radiographs. However, both modalities are generally unavailable to Special Operations Forces (SOF) medical personnel working in austere locations. These medical providers could potentially diagnose and treat rib fractures in any environment using a standardized approach that includes clarity of mechanism, pain relief, and point-of-care ultrasound (POCUS). This case demonstrates an approach to the diagnosis and treatment of a rib fracture in a 47-year-old male who presented to a military treatment facility with unlocalized flank and back pain, but the methods employed have applicability to the austere provider working far from the resources of a medical center.

Keywords: POCUS; rib fracture; perineural block; prolotherapy; musculoskeletal ultrasound

Mobility Solutions After a Lower Extremity Fracture and Applicability to Battlefield and Wilderness Medicine

Fall 2023

Childers W, Alderete JF, Eliason TD, Goldman SM, Nicolella DP, Pierrie SN, Stark GE, Studer NM, Wenke JC, Wilson JB, Dearth CL. 23(3). 91 - 100. (Journal Article)

Abstract

The potential for delayed evacuation of injured Service members from austere environments highlights the need to develop solutions that can stabilize a wound and enable mobility during these prolonged casualty care (PCC) scenarios. Lower extremity fractures have traditionally been treated by immobilization (splinting) followed by air evacuation - a paradigm not practical in PCC scenarios. In the civilian sector, treatment of extremity injuries sustained during remote recreational activities have similar challenges, particularly when adverse weather or terrain precludes early ground or air rescue. This review examines currently available fracture treatment solutions to include splinting, orthotic devices, and biological interventions and evaluates their feasibility: 1) for prolonged use in austere environments and 2) to enable patient mobilization. This review returned three common types of splints to include: a simple box splint, pneumatic splints, and traction splints. None of these splinting techniques allowed for ambulation. However, fixed facility-based orthotic interventions that include weight-bearing features may be combined with common splinting techniques to improve mobility. Biologically-focused technologies to stabilize a long bone fracture are still in their infancy. Integrating design features across these technologies could generate advanced treatments which would enable mobility, thus maximizing survivability until patient evacuation is feasible.

Keywords: prolonged casualty care; combat fractures; lower extremity; mobility; splinting; wilderness

Efficacy of the Military Tactical Emergency Tourniquet for Lower Extremity Arterial Occlusion Compared with the Combat Application Tourniquet: A Randomized Crossover Study

Summer 2023

Samutsakorn DK, Carius BM. 23(2). 36 - 39. (Journal Article)

Abstract

Introduction: Extremity bleeding and subsequent hemorrhagic shock is one of the main causes of preventable battlefield death, leading to mass-fielding of modern tourniquets, such as the Combat Application Tourniquet (CAT; Composite Resources). Numerous look-alike tourniquets, such as the Military Tactical Emergency Tourniquet (MTET; SZCTKlink), flood commercial markets, offering visually near-identical tourniquets for drastically reduced prices. We examined the performance of the MTET compared with that of the CAT. Methods: We undertook a randomized crossover trial to observe self-applied tourniquets to the lower extremity by combat medics, comparing the CAT to the MTET in application time and success rates, proven by loss of distal pulse assessed by Doppler ultrasound in <1 minute. Results: All 50 participants (100%) successfully applied the CAT versus 40 participants (80%) using the MTET (p = .0001). Median application time for the CAT (29.03 seconds; range, 18.63 to 59.50 seconds) was significantly less than those of successful MTET applications (35.27 seconds; range, 17.00 to 58.90 seconds) or failed MTET applications (72.26 seconds; range, 62.84 to 83.96 seconds) (p = .0012). Of 10 MTET failures, three (30%) were from application time >1 minute and seven (70%) from tourniquet mechanical failure. Conclusion: The MTET performed worse than the CAT did in all observed areas. Despite identical appearance, look-alike tourniquets should not be assumed to be equivalent in quality or functionality to robustly tested tourniquets.

Keywords: education; hemorrhage; bleeding control

A Review of Medical Evacuations Related to Dental Emergencies and Oral-Maxillofacial Injuries

Summer 2023

Qureshi I, Simecek J, Mitchener TA. 23(2). 82 - 87. (Journal Article)

Abstract

A literature review was performed to determine the frequency of medical evacuations (MEDEVAC) that are required for dental emergencies (DE) and oral-maxillofacial (OMF) injuries. Fourteen studies were reviewed altogether - eight which quantified evacuation of DEs or OMF injuries in military personnel (from 1982-2013) and six studies that discussed medical evacuation of DEs occurring in civilians working in offshore oil and gas rigs and wilderness expeditions (from 1976-2015). Among military personnel, DE/OMF issues were frequently among one of the top categories of medical evacuations, ranging from 2-16% of all evacuations. Among oil and gas industry workers, 5.3-14.6% of evacuations were dental-related, while one study of wilderness expeditions found that DEs ranked as the third most frequent type of injury that required evacuation. Previous studies have shown that dental and OMF problems often account for one of most frequently cited reasons for evacuation. However, due to the limited study base of DE/OMF medical evacuations, further research is needed to determine their impact on the cost of health care delivery

Keywords: medical evacuation; MEDEVAC; military personnel; dental emergencies; oil and gas industry; emergencies; dental care; health care costs; stomatognathic diseases

Tick-Borne Encephalitis: An Update for the Special Operations Forces Provider

Summer 2023

Kaur H, Shishido AA. 23(2). 110 - 113. (Journal Article)

Abstract

Tick-borne encephalitis (TBE) is a severe disease caused by the tick-borne encephalitis virus (TBEV). TBEV is endemic throughout Eurasia and can cause persistent neurologic deficits and death. Special Operations Forces (SOF) participating in field exercises or operations in TBE-endemic countries are at significantly increased risk of infection. Unlike Lyme disease and other tick-borne illnesses, transmission of TBEV can be immediate, and early tick removal does not reduce the risk of infection. While there are no virus-specific treatments available, the US Food and Drug Administration (FDA) recently approved a TBE vaccine that has yet to be incorporated into formal Department of Defense (DoD) recommendations. SOF medical providers should be aware of this disease entity and consider the TBE vaccine when planning exercises and operations in areas of responsibility (AORs) with TBE-endemic countries. This review serves as a refresher and update on the epidemiology, transmission, and management of TBE for the SOF provider.

Keywords: Tick-borne encephalitis; tick-borne disease; vector; biphasic; vaccines; biodefense

Warning: Tourniquets Risk Frostbite in Cold Weather

Spring 2023

Kragh JF, O'Conor DK. 23(1). 9 - 16. (Journal Article)

Abstract

We sought to better understand the frostbite risk during first-aid tourniquet use by reviewing information relevant to an association between tourniquet use and frostbite. However, there is little information concerning this subject, which may be of increasing importance because future conflicts against near-peer competitors may involve extreme cold weather environments. Historically, clinical frostbite cases with tourniquet use occurred in low frequency but in high severity when leading to limb amputation. The physiologic response of vasoconstriction to cold exposure leads to limb cooling and causes a reduction of limb blood flow, but cold-induced vasodilation ensues as periodic fluctuations that increase blood flow to hands and feet. In animal experiments, tourniquet use increased the development of frostbite. Evidence from human experiments also supports an association between tourniquet use and frostbite. Clinical guidance for caregiving to casualties at risk for frostbite with tourniquet use had previously been provided but slowly and progressively dropped out of documents. Conclusions: The cause of frostbite was deduced to be a sufficiently negative heat-transfer trend in local tissues, which tourniquet use may worsen because of decreasing tissue perfusion. An association between tourniquet use and frostbite exists but not as cause and effect. Tourniquet use increased the risk of the cold causing frostbite by allowing faster cooling of a limb because of reduced blood flow and lack of cold-induced vasodilation. Care providers above the level of the lay public are warned that first-aid tourniquet use in low-temperature (<0°C [<32°F]) environmental conditions risks frostbite.

Keywords: bleeding control and prevention; first aid; prehospital care; freezing cold injury; complication; wounds and injuries

Combat Casualties Treated With Intranasal Ketamine for Prehospital Analgesia: A Case Series

Spring 2023

Dubecq C, Montagnon R, Morand G, De Rocquigny G, Petit L, Peyrefitte S, Dubourg O, Pasquier P, Mahe P. 23(1). 84 - 87. (Case Reports)

Abstract

Optimal pain management is challenging in Tactical Combat Casualty Care (TCCC), particularly in remote and austere settings. In these situations, appropriate treatment for prehospital analgesia can be limited or delayed due to the lack of intravenous access. Several guidelines suggest to implement intranasal (IN) analgesia in French Armed Forces for forward combat casualty care (Sauvetage au Combat), similar to the US TCCC. Four medical teams from the French Medical Military Service were deployed to the Middle East and Sahel from August 2017 to March 2019 and used IN ketamine for analgesia in 76 trauma patients, out of a total of 259 treated casualties. IN administration of ketamine 50mg appeared to be safe and effective, alone or in addition to other opioid analgesics. It also had minimal side effects and led to a reduction in the doses of ketamine and morphine used by the intravenous (IV) route. The French Military Medical Service supports current developments for personal devices delivering individual doses of IN ketamine. However, further studies are needed to analyze its efficacy and safety in combat zones.

Keywords: military medicine; casualties; intranasal; ketamine; prehospital analgesia

Hydration: Tactical and Practical Strategies

Spring 2023

Scott J, Linderman JR, Deuster PA. 23(1). 88 - 91. (Journal Article)

Abstract

Full-spectrum Human Performance Optimization (HPO) is essential for Special Operations Forces (SOF). Adequate hydration is essential to all aspects of performance (physical and cognitive) and recovery. Water losses occur as a result of physical activity and can increase further depending on clothing and environmental conditions. Without intentional and appropriate strategic hydration planning, Operators are at increased risk for degradation in performance and exertional heat illness. The purpose of this article is to highlight current best practices for maintaining hydration before, during, and after activity, while considering various environmental conditions. Effective leadership and planning are necessary for preparing Operators for successful military operations.

Keywords: hydration; Special Operations Forces; SOF; human performance optimization; HPO; nutrition

Comparison of Warming Capabilities Between Buddy Lite, enFlow, and Thermal Angel for US Army Medical Personnel in Austere Conditions: A Literature Review

Winter 2022

Vallier DJ, Anderson WJ, Snelson JV, Yauger YJ, Felix JR, Alford KI, Bermoy WA. 22(4). 9 - 13. (Journal Article)

Abstract

US Army Forward Surgical Elements (FSEs) are highly mobile teams that provide damage control surgery (DCS) and damage control resuscitation (DCR) in austere locations that often lack standard hospital utilities (electricity, heat, food, and water). FSEs rely on portable battery-operated intravenous (IV) fluid warmers to remain light and mobile. However, their ability to warm blood in a massive resuscitation requires additional analysis. The purpose of this literature review is to examine the three most common battery-operated IV fluid warmers as determined by type and quantity listed on the Mission Table of Organization and Equipment (MTOE) of organic mobile medical units. These include the Buddy Lite, enFlow, and Thermal Angel, which are available to deployed US Army FSEs for blood resuscitation therapy. Based on limited available evidence, the enFlow produced higher outlet temperatures, effectively warmed greater volumes, reached the time to peak temperature faster, and produced greatest flow rates, with cool saline (5-10°C), compared to the Thermal Angel and Buddy Lite. However, recently the US Food and Drug Administration (FDA) issued a Class 1 recall on enFlow cartridges. Testing demonstrated aluminum elution from enFlow cartridges into IV solutions, thereby exposing patients to potentially unsafe aluminum levels. The authors recommend FSE units conduct a 100% enFlow cartridge inventory and seek an alternative IV fluid warming system prior to enFlow cartridge disposal. If an alternative does not exist, or the alternative warming system does not fit mission requirements, then medical personnel must carefully weigh the risks and benefits associated with the enFlow delivery system.

Keywords: Thermal Angel; enFlow; Buddy Lite; fluid warmer; intravenous fluids, IVF; cartridge

Incidence of Airway Interventions in the Setting of Serious Facial Trauma

Winter 2022

Schauer S, Naylor JF, Fisher AD, Becker TE, April MD. 22(4). 18 - 21. (Journal Article)

Abstract

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.

Keywords: prehospital; airway; facial; trauma; military

Airway and Hypothermia Prevention: and Treatment via STEAM The System for Thermogenic Emergency Airway Management

Winter 2022

Stevens R, Pierce B, Tilley L. 22(4). 72 - 76. (Journal Article)

Abstract

Military medicine has made significant advancements in decreasing mortality by addressing the lethal triad - metabolic acidosis, coagulopathy, and hypothermia. However, casualties are still succumbing to injury. Recent conflict zones have led to the development of remarkable life-saving innovations, including the management of compressible hemorrhage and whole blood transfusions. Nevertheless, hypothermia prevention and treatment techniques remain relatively unchanged. Hypothermia prevention is anticipated to become more critical in future operations due to a predicted increase in evacuation times and reliance on Prolonged Casualty Care (PCC). This is likely secondary to increasingly distanced battlespaces and the mobility challenges of operating in semi-/non-permissive environments. Innovation is essential to combat this threat via active airway rewarming in the vulnerable patient. Thus, we propose the development, fabrication, and efficacy testing of a device in which we estimate being able to control temperature and humidity at physiologic levels in the PCC setting and beyond.

Keywords: Advanced Trauma Life Support care; airway management; critical care; emergency medicine; intellectual property; military medicine; patent; prehospital emergency care; prolonged casualty care; prolonged field care; resuscitation; technological innovations; war-related trauma; wilderness medicine hypothermia

Whole Blood Storage Temperature Investigation in Austere Environments

Fall 2022

Avila CO, Sayson SC, Bennett B. 22(3). 19 - 21. (Journal Article)

Abstract

Introduction: Military medical research has affirmed that early administration of blood products and timely treatment save lives. The US Navy's Expeditionary Resuscitative Surgical System (ERSS) is a Role 2 Light Maneuver team that functions close to the point of injury, administering blood products and providing damage-control resuscitation and surgery. However, information is lacking on the logistical constraints regarding provisions for and the stability of blood products in austere environments. Methods: ERSS conducted a study on the United States Central Command (USCENTCOM) area of responsibility. Expired but properly stored units of stored whole blood (SWB) were subjected to five different storage conditions, including combinations of passive and active refrigeration. The SWB was monitored continuously, including for external ambient temperatures. The time for the SWB to rise above the threshold temperature was recorded. Results: The main outcome of the study was the time for the SWB to rise above the recommended storage temperature. Average ambient temperature during the experiment involving conditions 1 through 4 was 25.6°C (78.08°F). Average ambient temperature during the experiment involving condition 5 was 34.8°C (94.64°F). Blood temperature reached the 6°C (42.8°F) threshold within 90 minutes in conditions 1 and 2, which included control and chemically activated ice packs in the thermal insulated chamber (TIC). Condition 2 included prechilling the TIC in a standard refrigerator to 4°C (39.2°F), which kept the units of SWB below the threshold temperature for 490 minutes (approximately 8 hours). Condition 4 entailed prechilling the TIC in a standard freezer to 0.4°C (32.72°F), thus keeping the units of SWB below threshold for 2,160 minutes (i.e., 36 hours). Condition 5 consisted of prechilling the TIC to 3.9°C (39.02°F) in the combat blood refrigerator, which kept the SWB units below the threshold for 780 minutes (i.e., 13 hours), despite a higher average ambient temperature of almost +10°C (50°F). Conclusion: Combining active and passive refrigeration methods will increase the time before SWB rises above the threshold temperature. We demonstrate an adaptable approach of preserving blood product temperature despite refrigeration power failure in austere settings, thereby maintaining mission readiness to increase the survival of potential casualties.

Keywords: stored whole blood; forward deployed surgical team; austere environments; walking blood bank; fresh whole blood; Role 2 care; blood transfusion; Golden Hour Offset Surgical Team

Performance Evaluation of the Solo-T and the Combat Application Tourniquet in a Perfused Cadaver Model

Fall 2022

Holinga GJ, Foor JS, Van Horn SL, McGuire JE. 22(3). 49 - 55. (Journal Article)

Abstract

Purpose: We evaluated a 10.2-cm-wide, minimally elastic, adhesive wrap-based tourniquet (Solo-T or ST) alongside a 3.8-cm-wide windlass-based tourniquet (Combat Application Tourniquet Generation 7, or CAT) to determine if the tension wrap-tightened ST could deliver hemorrhage control equivalent to the windlass-tightened CAT. Methods: A cadaver model was used to simulate lower-thigh femoral arterial hemorrhage at "normal" (146 ± 5mmHg) and "elevated" (471 ± 3mmHg) perfusion pressures (mean ± standard error). Three study participants used the ST and CAT to control hemorrhage during 48 timed trials. Arterial occlusion was established by Doppler ultrasound and tourniquet performance was quantified by under-tourniquet pressure cuffs. Results: Participants achieved 100% (24/24) occlusion success rates and reported similar ease of use for both tourniquets. Occlusion and application times (mean ± standard error) were similar (p > .05) for the ST and CAT under "normal" (occlusion, ST: 25 ± 2 seconds, CAT: 22 ± 2 seconds; application, ST: 27 ± 2 seconds, CAT: 26 ± 2 seconds) and "elevated" (occlusion, ST: 24 ± 7 seconds, CAT: 24 ± 7 seconds; application, ST: 25 ± 7 seconds, CAT: 25 ± 7 seconds) perfusion alike. The ST mean completion pressures (mean ± standard error) were > 40% lower than the CAT under both "normal" perfusion (ST: 110 ± 20mmHg; CAT: 210 ± 30mmHg; p = 0.009) and "elevated" perfusion (ST: 190 ± 50mmHg; CAT: 340 ± 30mmHg; p = 0.03). Conclusion: The adhesive wrap-based ST tourniquet delivered equivalent hemorrhage control performance at significantly lower completion pressures than the CAT.

Keywords: first aid; hemorrhage control; perfused cadaver; tourniquet; tourniquet pressure; trauma care

Operational Consideration for Definitive Airway Management in the Austere Setting: A Case Report

Fall 2022

Morvan J, Cotte J, des Deserts MD, Worlton T, Menini W, Cathelinaud O, Pasquier P. 22(3). 90 - 93. (Journal Article)

Abstract

In modern and asymmetric conflicts, traumatic airway obstruction caused by penetrating injury to the face and neck anatomy is the second leading cause of preventable mortality. Definitive airway management in the emergency setting is most commonly accomplished by endotracheal intubation. When this fails or is not possible, a surgical airway, usually cricothyrotomy, is indicated. The clinical choice for establishing a definitive airway in the austere setting is impacted by operational factors such as a mass casualty incident or availability and type of casualty evacuation. This is a case report of a patient with severe cervicofacial injuries with imminent airway compromise in the setting of a mass casualty incident, without possibility of sedation and mechanical ventilation during his evacuation. The authors seek to highlight the considerations and lessons learned for emergency cricothyrotomy.

Keywords: Tactical Combat Casualty Care; cricothyrotomy; airway; mass casualties; medical evacuation

Bilateral Pneumothoraces in a Tandem Parachuting Passenger Without Traumatic Impact: A Case Report

Fall 2022

Fedor PJ, Riley B, Fowl DA, Donahue A. 22(3). 94 - 97. (Case Reports)

Abstract

In parachuting, orthopedic and head injuries are well-documented risks associated with the parachute deployment and landing phases. Thoracic injuries have only been seen on rare occasion in conjunction with direct impact trauma. In this report, we detail a case of a young, healthy, tandem skydiving passenger who suffered bilateral pneumothoraces with delayed symptom onset, with no identifiable injury during the jump or landing. Exploring the forces of the parachute "opening shock," we suggest a plausible compressive mechanism for this novel presentation, as well as briefly discuss the options for diagnosis and conservative management of pneumothorax in the operational context. While this is an exceedingly rare event, pneumothorax should be considered in patients complaining of thoracic symptoms following a skydive.

Keywords: pneumothorax; prolonged field care; military medicine; prehospital ultrasound; parachute injuries; parachuting

Analgesia and Sedation in the Prehospital Setting: A Critical Care Viewpoint

Summer 2022

DesRosiers TT, Anderson JL, Adams B, Carver RA. 22(2). 48 - 54. (Journal Article)

Abstract

Pain is one of the most common complaints of battlefield casualties, and unique considerations apply in the tactical environment when managing the pain of wounded service members. The resource constraints commonly experienced in an operational setting, plus the likelihood of prolonged casualty care by medics or corpsmen on future battlefields, necessitates a review of analgesia and sedation in the prehospital setting. Four clinical scenarios highlight the spectrum of analgesia and sedation that may be necessary in this prehospital and/or austere environment.

Keywords: traumatic brain injury; pathophysiology; prehospital management; critical care

Prehospital Anemia Care A Review of Symptoms, Evaluation, and Management

Summer 2022

Rankin CJ, Fetherston T, Ballentine CD, Adams B, Long B, Carius BM. 22(2). 69 - 74. (Journal Article)

Abstract

The ongoing evolution of prehospital medical care continues to advance beyond immediate triage care. Prehospital care is even more important to consider in theaters with extended evacuation times and limited local medical assets. Although blood loss is often associated with settings of acute traumatic hemorrhage in military medicine, the possibility for other hematologic compromise necessitating urgent action requires medics operating in these environments to have a fundamental knowledge of the pathophysiology, manifestations, and stabilization measures of anemia to aid their patients prior to, or in lieu of, evacuation. Continued development of and access to point-of-care testing in increasingly forward-deployed settings further enable medics to perform these tasks. Here, we provide a brief review of hemoglobin function and composition, and presentation and management considerations of anemia, to assist medics in their treatment efforts. We also address specific concerns for battlefield and atraumatic presentations.

Keywords: hemoglobin; anemia; prehospital care; blood loss, hemorrhage; military; laboratory; malaria; hemolysis; bleeding; transfusion

Prehospital Electrolyte Care: A Review of Symptoms, Evaluation, and Management

Summer 2022

Painter A, Carius BM. 22(2). 80 - 86. (Journal Article)

Abstract

Ongoing evolution of prehospital medical care continues to advance beyond tactical field care scenarios in the consideration of prolonged field care. This is even more important to consider in theaters with extended evacuation times and limited local medical assets. The critical regulatory functions of electrolytes such as sodium, potassium, calcium, and glucose require medics operating in these environments to have a strong, fundamental knowledge of the principles, manifestations, and initial stabilization measures to aid their patients prior to, or in lieu of evacuation. Continued development and access to point of care testing in increasingly forward deployed settings further enables medics to perform these tasks. Here, we provide a brief review of these vital electrolytes, as well as additional kidney function evaluation considerations, to assist medics in their treatment efforts. Specific concerns for battlefield and atraumatic presentations are addressed.

Keywords: military; laboratory; sodium; potassium; calcium; glucose; electrolytes; creatinine

Prolonged Casualty Care Guidelines 21 December 2021

Spring 2022

Remley MA, Loos PE, Riesberg JC. 22(1). 18 - 47. (Classical Conference)

Abstract

Keywords:

The Myths of Uncontrolled Emergence Reactions and Consideration to Stop Mandatory, Protocolled Midazolam Coadministration With Ketamine

Spring 2022

Hiller HM, Drew B, Fisher AD, Cuthrell M, Spradling JC. 22(1). 49 - 54. (Journal Article)

Abstract

Ketamine continues to demonstrate its utility and safety in the austere and prehospital environment, but myths persist regarding the frequency of behavioral disturbances and unpleasant reactions. These myths have led to protocolled midazolam co-administration. Properties of midazolam and other benzodiazepines have the potential to cause significant morbidity and potential mortality. Because of this risk, benzodiazepines should only be administered when the treating provider determines that the patient's symptoms warrant it. We also present evidence that agitation and altered mental status (AMS) encountered with ketamine occurs during titration of lower pain control regimens and is much less likely to occur with higher doses. As such, in most prehospital situations, the treatment for this "incomplete dissociation" is more ketamine, not the addition of a potentially dangerous benzodiazepine.

Keywords: ketamine; emergence; midazolam; Versed; dissociation

Expeditionary Mechanical Ventilation in Conjunction With Extracorporeal Life Support During Ground Transport

Spring 2022

Beely BM, Harea GT, Wendorff DS, Choi JH, Sieck K, Karaliou V, Cannon JW, Lantry JH, Cancio LC, Sams VG, Batchinsky AI. 22(1). 64 - 69. (Journal Article)

Abstract

Background: We assessed the use of an FDA-cleared transport ventilator with limited functions and settings during ground transport in a swine model of ground evacuation. We hypothesized that when used as an adjunct to extracorporeal life support (ECLS), the device would enable safe mobile ventilatory support during ground evacuation. Methods: Female Yorkshire swine (n = 11; mean, 52.4 ± 1.3 kg) were sedated and anesthetized and received mechanical ventilation (MV) with a standard intensive care unit (ICU) ventilator and were transitioned to the Simplified Automated Ventilator II (SAVe II; AutoMedx) during ground transport. MV served as an adjunct to ECLS in all animals. Ventilator performance was assessed in the uninjured state on day 1 and after bilateral pulmonary contusion on day 2. Data were collected pre- and post-transport on both days. Results: During 33 transports, the SAVe II provided similar ventilation support as the ICU ventilator. Mean total transport time was 38.8 ± 2.1 minutes. The peak inspiratory pressure (PIP) limit was the only variable to show consistent differences pre- and post-transport and between ventilators. No adverse events occurred. Conclusion: As an adjunctive supportive device during ground transport, the SAVe II performed adequately without failure or degradation in subject status. Further testing is warranted to elucidate the clinical limits of this device during standalone use.

Keywords: acute respiratory distress syndrome; trauma; extracorporeal life support; Mechanical Ventilation; expeditionary ground evacuation

A Prospective, Feasibility Assessment of a Novel, Disposable Video Laryngoscope With Special Operations Medical Personnel in a Mobile Helicopter Simulation Setting

Winter 2021

Schauer SG, Mendez J, Uhaa N, Hudson IL, Weymouth WL. 21(4). 26 - 29. (Journal Article)

Abstract

Background: Video laryngoscopy (VL) is shown to improve first-pass success rates and decrease complications in intubations, especially in novice proceduralists. However, the currently fielded VL devices are cost-prohibitive for dispersion across the battlespace. The novel i-view VL is a low-cost, disposable VL device that may serve as a potential solution. We sought to perform end-user performance testing and solicit feedback. Methods: We prospectively enrolled Special Operations flight medics with the 160th Special Operations Aviation Regiment at Hunter Army Airfield, Savannah, Georgia. We asked them to perform an intubation using a synthetic cadaver model while in a mobile helicopter simulation setting. We surveyed their feedback afterward. Results: The median age of participants was 30 and all were male. Of those, 60% reported previous combat deployments, with a median of 20 months of deployment time. Of the 10, 90% were successful with intubation, with 60% on first-pass success with an average of 83 seconds time to intubation. Most had a grade 1 view. Most agreed or strongly agreed that it was easy to use (70%), with half (50%) reporting they would use it in the deployed setting. Several made comments about the screen not being bright enough and would prefer one with a rotating display. Conclusions: We found a high proportion of success for intubation in the mobile simulator and a high satisfaction rate for this device by Special Operations Forces medics.

Keywords: i-view; medic; airway; intubation; flight; helicopter; laryngoscopy

Use of Topical Hemostatic Dressings in an Extended Field Care Model

Winter 2021

Welch M, Barratt J, Peters A, Wright C. 21(4). 63 - 65. (Journal Article)

Abstract

Background: We sought to test whether Celox topical hemostatic dressing (Medtrade Products) would maintain hemostasis in extended use. Methods: An anesthetized swine underwent bilateral arteriotomies and treatment with topical hemostatic dressings in line with the Kheirabadi method. The dressings were covered with standard field dressings, and these were visually inspected for bleeding every 2 hours until 8 hours, when the swine was euthanized. Results: There was no evidence of rebleeding at any point up to and including 8 hours. The Celox dressings maintained hemostasis in extended use. Conclusion: Celox topical hemostatic dressing is effective for extended use and maintains hemostasis. It should be considered for use in situations in which evacuation and definitive care may be delayed.

Keywords: hemostatic; trauma; prehospital; hemorrhage; military

Development of a Swine Polytrauma Model in the Absence of Fluid Resuscitation

Winter 2021

Abdou H, Patel N, Edwards J, Richmond MJ, Elansary N, Du J, Poliner D, Morrison JJ. 21(4). 77 - 82. (Journal Article)

Abstract

Background: In locations in which access to resuscitative therapy may be limited, treating polytraumatized patients present a challenge. There is a pressing need for adjuncts that can be delivered in these settings. To assess these adjuncts, a model representative of this clinical scenario is necessary. We aimed to develop a hemorrhage and polytrauma model in the absence of fluid resuscitation. Materials and Methods: This study consisted of two parts: pulmonary contusion dose-finding (n = 6) and polytrauma with evaluation of varying hemorrhage volumes (n = 6). We applied three, six, or nine nonpenetrating captive bolt-gun discharges to the dose-finding group and obtained computed tomography (CT) images. We segmented images to assess contusion volumes. We subjected the second group to tibial fracture, pulmonary contusion, and controlled hemorrhage of 20%, 30%, or 40% and observed for 3 hours or until death. We used Kaplan-Meier analysis to assess survival. We also assessed hemodynamic and metabolic parameters. Results: Contusion volumes for three, six, and nine nonpenetrating captive bolt-gun discharges were 24 ± 28, 50 ± 31, and 63 ± 77 cm3, respectively (p = .679). Animals receiving at least six discharges suffered concomitant parenchymal laceration, whereas one of two swine subjected to three discharges had lacerations. Mortality was 100% at 12 and 115 minutes in the 40% and 30% hemorrhage groups, respectively, and 50% at 3 hours in the 20% group. Conclusion: This study characterizes a titratable hemorrhage and polytrauma model in the absence of fluid resuscitation. This model can be useful in evaluating resuscitative adjuncts that can be delivered in areas remote to healthcare access.

Keywords: Polytrauma model; pulmonary contusion; controlled hemorrhage; tibial fracture; delayed medical care; prolonged casualty care; prolonged field care

Chemical Warfare Agents in Terrorist Attacks: An Interregional Comparison, Tactical Response Implications, and the Emergence of Counterterrorism Medicine

Fall 2021

Tin D, Pepper M, Hart A, Hertelendy A, Ciottone G. 21(3). 51 - 54. (Journal Article)

Abstract

Background: Terrorist attacks are growing in frequency, increasing concerns about chemical warfare agents (CWAs). Asphyxiants (e.g., cyanide), opioids (e.g., carfentanyl), and nerve agents (e.g., ricin) represent some of the most lethal CWAs. Our aim was to define the epidemiology of CWA use in terrorism and detail specific agents used to allow for the development of training programs for responders. Methods: The open-source Global Terrorism Database (GTD) was searched for all chemical attacks from January 1, 1970, to December 31, 2018. Attacks were included when they fulfilled the terrorism-related criteria as set forth in the internal Codebook of the GTD. Events meeting only partial criteria were excluded. Results: A total of 347 terrorism-related chemical events occurred, with 921 fatalities and 13,361 nonfatal injuries (NFIs) recorded during the study period. South Asia accounted for nearly 30% (101 of 347) of CWA attacks, with 73 of 101 occurring in Afghanistan. The Taliban was implicated in 40 of 101 events utilizing a mixture of agents, including unknown chemical gases (likely representing trials of a number of different chemicals), contamination of water sources with pesticides, and the use of corrosive acid. The largest death toll from a single event (200 fatalities) was attributed to a cult-related mass murder in the Kasese District of Uganda in March 2000. East Asia sustained the highest NFI toll of 7,007 as a result of chemical attacks; 5,500 were attributed to the Tokyo subway sarin gas attack of 1995 by Aum Shinrikyo. Conclusion: The use of CWAs remains a concern given the rising rate of terrorist events. First responders and healthcare workers should be aware of potential chemical hazards that have been used regionally and globally and should train and prepare to respond appropriately.

Keywords: chemical warfare agents; terrorist attacks; counter-terrorism medicine

Impact of a 10,000-m Cold-Water Swim on Norwegian Naval Special Forces Recruits

Fall 2021

Melau J, Hisdal J, Solberg PA. 21(3). 55 - 59. (Journal Article)

Abstract

Background: Special Operation Forces (SOF) operate regularly in extreme environmental conditions that may affect tactical and physical performance. The main aims of the present study were to elucidate the impact of a long cold-water swim on SOF recruits' dexterity, performance, and reaction time. Material and Methods: Eleven recruits from Norwegian Naval Special Operation Command (NORNAVSOC) that were participating in a 10,000-m open water swim with a dry suit in 5°C cold water volunteered to participate in this study. The exercise was part of their training. Grip strength, lower body power, and dexterity were measured before, immediately after, and 24 hours after the swim. In addition, core and skin temperatures were measured continuously during the swim and until 45 minutes after the swim. Results: After the swim, moderate to large reductions in core temperature, lower body power, and reaction time were observed. Moreover, very large to extremely large reductions in skin temperature, grip strength, and dexterity were also observed. Conclusion: These results demonstrate that exposure to a 10,000-m swim in 5°C water using standard equipment led to a significant drop in the recruits' temperature and performance. These findings could have a meaningful impact on the planning of training, operations, and gear used for SOF.

Keywords: stress hormones; body temperature; skin temperature; military medicine; swimming; physical fitness; combat swimmer; combat diver

Efficacy of Commercial Chest Seal Adherence and Tension Pneumothorax Prevention: A Systematic Review of Quantitative Studies

Fall 2021

Paquette R, Quinene M, Blackbourne LH, Allen PB. 21(3). 78 - 85. (Journal Article)

Abstract

Background: Penetrating thoracic injuries account for an essential subset of battlefield and civilian injuries that result in death. Current recommendations are to use commercially available nonocclusive chest seals. We review current evidence for which chest seal(s) is likely to be the most effective in treating open pneumothoraces. Methods: A systematic review was conducted in accordance with the PRIMSA 2009 standard systematic review methodology, except where noted. The databases Pubmed, MEDLINE, CINAHL, Scopus, and gray sources were searched for all English-language, full-manuscript, experimental, quantitative studies of humans and animals concerning seal adherence or their efficacy at preventing tension pneumothoraces published between 1990 and 2020. A numerical analysis was used to provide the consensus recommendation. Results: Of 683 eligible identified articles [PubMed 528 (77.3%), Scopus 87 (12.7%), CINAHL 67 (9.8%), one (0.1%) unpublished], six (0.9%) articles were included. Synthesis of all studies' results suggests a consensus recommendation for the Hyfin Vent Chest Seal and Russell Chest Seal. These two were the most effective chest seals, as previously investigated in a quantifiable, experimental study. Conclusion: While chest seals are recommended in civilian and military prehospital medicine to improve patient survival, current evidence concerning the individual device's efficacy is limited. Further scientific, quantitative research is needed to clarify which commercially available chest seals are most effective and provide patients with penetrating chest trauma the best possible method for preventing or mitigating tension pneumothoraces.

Keywords: pneumothorax; chest seal; chest trauma; Tactical Combat Casualty Care; advanced trauma life support; systematic review

Caffeine Gum Does Not Improve Marksmanship, Bound Duration, Susceptibility to Enemy Fire, or Cognitive Performance During Tactical Combat Movement Simulation

Fall 2021

Stein JA, Hepler TC, DeBlauw JA, Beattie CM, Beshirs CD, Holte KM, Kurtz BK, Heinrich KM. 21(3). 86 - 92. (Journal Article)

Abstract

Background: Military personnel supplement caffeine as a countermeasure during unavoidable sustained wakefulness. However, its utility in combat-relevant tasks is unknown. This study examined the effects of caffeinated gum on performance in a tactical combat movement simulation. Materials and Methods: Healthy men (n = 30) and women (n = 9) (age = 25.3 ± 6.8 years; mass 75.1 ± 13.1 kg) completed a marksmanship with a cognitive workload (CWL) assessment and a fire-andmove simulation (16 6-m bounds) in experimental conditions (placebo versus caffeinated gum, 4mg/kg). Susceptibility to enemy fire was modeled on bound duration during the fireand- move simulation. Results: Across both conditions, bound duration and susceptibility to enemy fire increased by 9.3% and 7.8%, respectively (p = .001). Cognitive performance decreased after the fire-and-move simulation across both conditions (p < .05). However, bound duration, susceptibility to enemy fire, marksmanship, and cognitive performance did not differ between the caffeine and placebo conditions. Conclusion: These data do not support a benefit of using caffeinated gum to improve simulated tactical combat movements.

Keywords: caffeine gum; marksmanship; bound duration; enemy fire; cognitive performance; tactical combat movement simulation

Military Use of Point of Care Ultrasound (POCUS)

Summer 2021

Savell SC, Baldwin DS, Blessing A, Medelllin KL, Savell CB, Maddry JK. 21(2). 35 - 42. (Journal Article)

Abstract

Background: Point of care ultrasound (POCUS) offers multiple capabilities in a relatively small, lightweight device to military clinicians of all types and levels in multiple environments. Its application in diagnostics, procedural guidance, and patient monitoring has not been fully explored by the Military Health System (MHS). The purpose of this narrative review of the literature was to examine the overall use of POCUS in military settings, as well as the level of ultrasound training provided. Methods: Studies related to use of POCUS by military clinicians with reported sensitivity/specificity, accuracy of exam, and/or clinical decision impact met inclusion criteria. After initial topical review and removal of duplicates, two authors selected 17 papers for consideration for inclusion. Four of the authors reviewed the 17 papers and determined the final inclusion of 14 studies. Results: We identified seven prospective studies, of which three randomized subjects to groups. Five reports described use of POCUS in patients, two used healthy volunteers, two were in simulation training environments, four used animal models to simulate specific conditions, and one used a cadaver model. Clinician subjects ranged from one to 34. Conventional medics were subjects in six studies. Four studies included special operations medics. One study included nonmedical food service inspectors. The use of ultrasound in theater by deployed consultant radiologists is described in three reports. Conclusions: Military clinicians demonstrated the ability to perform focused exams, including FAST exams and fracture detection with acceptable sensitivity and specificity. POCUS in the hands of trained military clinicians has the potential to improve diagnostic accuracy and ultimately care of the war fighter.

Keywords: ultrasound; military; point of care ultrasound; POCUS

An Analysis of Prehospital Trauma Registry After-Action Reviews in Afghanistan

Summer 2021

Carius BM, Dodge PM, Fisher AD, Loos PE, Thompson D, Schauer SG. 21(2). 49 - 53. (Journal Article)

Abstract

Background: After-action reviews (AARs) in the Prehospital Trauma Registry (PHTR) enable performance improvements and provide commanders feedback on care delivered at Role 1. No published data exist exploring overall trends of end-user performance-improvement feedback. Methods: We performed an expert panel review of AARs within the PHTR in Afghanistan from January 2013 to September 2014. When possible, we categorized our findings and selected relevant medical provider comments. Results: Of 737 registered patient encounters found, 592 (80%) had AAR documentation. Most AAR patients were male (98%, n = 578), injured by explosion (48%, n = 283), and categorized for urgent evacuation (64%, n = 377). Nearly two thirds of AARs stated areas needing improvement (64%, n = 376), while the remainder left the improvement section blank (23%, n = 139) or specified no improvements (13%, n = 76). The most frequently cited areas for improvement were medical knowledge (23%, n = 136), evacuation coordination (19%, n = 115), and first responder training (16%, n = 95). Conclusions: Our expert panel reviewed AARs within the PHTR and found substantial numbers of AARs without improvements recommended, which limits quality improvement capabilities. Our analysis supports previous calls for better documentation of medical care in the prehospital combat setting.

Keywords: trauma; prehospital; military; after action review; performance

A Survey of Tranexamic Acid Use by US Tactical Emergency Medical Support Providers

Summer 2021

McGuire SS, Klassen AB, Mullan AF, Sztajnkrycer MD. 21(2). 72 - 76. (Journal Article)

Abstract

Background: Tactical Emergency Medical Support (TEMS) providers may encounter severe traumatic injuries, with associated hemorrhagic shock, coagulopathy, and hyperfibrinolysis. Tranexamic acid (TXA) administration represents a potential intervention in this operational environment. This study evaluated TXA availability and use among US tactical medical personnel supporting law enforcement tactical teams. Methods: An anonymous on-line survey of the American College of Emergency Physicians (ACEP) Tactical Emergency Medicine (TEM) section was administered. Results: Fifty respondents were included in the final study. Fifty-four percent reported TXA availability, with 14% reporting its use at least once in the past year. Additional available resuscitative products included crystalloids (88%) and packed red blood cells (6%). Twenty-five respondents reported managing ≥ 1 patient(s) with hemorrhagic shock in the past year. Resuscitative measures included crystalloids (96%), TXA (68%), and blood products (16%). Overall, 88% of respondents were supportive of TXA use. Full-time teams, those with = 3 monthly callouts, and teams that carried blood products were more likely to have TXA. Conclusions: Half of respondents reported managing a patient with hemorrhagic shock in the past year. Although 88% were supportive of TXA use, only 54% reported availability. Tactical teams with higher call volume and more resources were more likely to carry TXA. Further studies evaluating TEMS patient wounding patterns and barriers to TXA utilization are required.

Keywords: TXA; TEMS; tactical EMS; tranexamic acid; operational medicine; trauma-induced coagulopathy

Performance Characteristics of Fluid Warming Technology in Austere Environments

Spring 2021

Blakeman T, Fowler J, Branson R, Petro M, Rodriquez D. 21(1). 18 - 24. (Journal Article)

Abstract

Resuscitation of the critically ill or injured is a significant and complex task in any setting, often complicated by environmental influences. Hypothermia is one of the components of the "Triad of Death" in trauma patients. Devices for warming IV fluids in the austere environment must be small and portable, able to operate on battery power, warm fluids to normal body temperature (37°C), and perform under various conditions, including at altitude. The authors evaluated four portable fluid warmers that are currently fielded or have potential for use in military environments.

Keywords: intravenous fluids; fluid warning; resuscitation; hypothermia

Commercial and Improvised Pelvic Compression Devices: Applied Force and Implications for Hemorrhage Control

Spring 2021

Bailey RA, Simon EM, Kreiner A, Powers D, Baker L, Giles C, Sweet R, Rush SC. 21(1). 44 - 48. (Journal Article)

Abstract

Uncontrolled hemorrhage secondary to unstable pelvic fractures is a preventable cause of prehospital death in the military and civilian sectors. Because the mortality rate associated with unstable pelvic ring injuries exceeds 50%, the use of external compression devices for associated hemorrhage control is paramount. During mass casualty incidents and in austere settings, the need for multiple external compression devices may arise. In assessing the efficacy of these devices, the magnitude of applied force has been offered as a surrogate measure of pubic symphysis diastasis reduction and subsequent hemostasis. This study offers a sensor-circuit assessment of applied force for a convenience sample of pelvic compression devices. The SAM® (structural aluminum malleable) Pelvic Sling II (SAM Medical) and improvised compression devices, including a SAM Splint tightened by a Combat Application Tourniquet® (C-A-T; North American Rescue) and a SAM® Splint tightened by a cravat, as well as two joined cravats and a standard-issue military belt, were assessed in male and female subjects. As hypothesized, compressive forces applied to the pelvis did not vary significantly based on device operator, subject sex, and subject body fat percentage. The use of the military belt as an improvised method to obtain pelvic stabilization is not advised.

Keywords: pelvic ring fractures; pelvic injuries; commercial pelvic compression devices; improvised pelvic compression devices; mass casualty incidents

Prehospital Needle Decompression Improves Clinical Outcomes in Helicopter Evacuation Patients With Multisystem Trauma: A Multicenter Study

Spring 2021

Henry R, Ghafil C, Golden A, Matsushima K, Eckstein M, Foran CP, Theeuwen H, Bentley DE, Inaba K, Strumwasser A. 21(1). 49 - 54. (Journal Article)

Abstract

Background: The utility of prehospital thoracic needle decompression (ND) for tension physiology in the civilian setting continues to be debated. We attempted to provide objective evidence for clinical improvement when ND is performed and determine whether technical success is associated with provider factors. We also attempted to determine whether certain clinical scenarios are more predictive than others of successful improvement in symptoms when ND is performed. Methods: Prehospital ND data acquired from one air ambulance service serving 79 trauma centers consisted of 143 patients (n = 143; ND attempts = 172). Demographic and clinical outcome data were retrospectively reviewed. Patients were stratified by prehospital characteristics and indications. Objective outcomes were measured as improvement in vital signs, subjective patient assessment, and physical examination findings. Univariate analysis was performed using chi-square for variable proportions and unpaired Student's t-test for variable means; p < .05 was considered statistically significant. Results: The success rate of ND performed for hypoxia (70.5%) was notably higher than ND performed for hemodynamic instability (20.3%; p < .01) or cardiac arrest (0%; p < .01). Compared to vital sign parameters, clinical examination findings as part of the indication for ND did not reliably predict technical success (p > .52 for all indications). No difference was observed comparing registered nurse versus paramedic (p = .23), diameter of catheter (p < .13 for all), or length of catheter (p = .12). Conclusion: Prehospital ND should be considered in the appropriate clinical setting. Outcomes are less reliable in cases of cardiopulmonary arrest or hypotension with respiratory symptoms; however, this should not deter prehospital providers from attempting ND when clinically indicated. Additionally, the success rate of prehospital ND does not appear to be related to catheter type or the role of the performing provider.

Keywords: needle decompression; prehospital emergency care; tension physiology; cardiopulmonary arrest

Sepsis Management in Prolonged Field Care: 28 October 2020

Winter 2020

Rapp J, Keenan S, Taylor D, Rapp A, Turconi M, Maves R, Kavanaugh M, Makati D, Powell D, Loos PE, Sarkisian S, Sakhuja A, Mosely DS, Shackelford SA. 20(4). 27 - 39. (Journal Article)

Abstract

This Role 1 prolonged field care (PFC) guideline is intended for use in the austere environment when evacuation to higher level of care is not immediately possible. A provider must first be an expert in Tactical Combat Casualty Care (TCCC). The intent of this guideline is to provide a functional, evidence-based and experience-based solution to those individuals who must manage patients suspected of having or diagnosed with sepsis in an austere environment. Emphasis is placed on the basics of diagnosis and treatment using the tools most familiar to a Role 1 provider. Ideal hospital techniques are adapted to meet the limitations of austere environments while still maintaining the highest standards of care possible. Sepsis and septic shock are medical emergencies. Patients suspected of having either of these conditions should be immediately evacuated out of the austere environment to higher echelons of care. These patients are often complex, requiring 24-hour monitoring, critical care skills, and a great deal of resources to treat. Obtaining evacuation is the highest treatment priority for these patients. This Clinical Practice Guideline (CPG) uses the minimum, better, best paradigm familiar to PFC and gives medics of varying capabilities and resources options for treatment.

Keywords: prolonged field care; Tactical Combat Casualty Care; sepsis; austere environment

Frostbite: Pathophysiology, Epidemiology, Diagnosis, Treatment, and Prevention

Winter 2020

Knapik JJ, Reynolds KL, Castellani JW. 20(4). 123 - 135. (Journal Article)

Abstract

Frostbite can occur during cold-weather operations when the temperature is <0°C (<32°F). When skin temperature is ≤-4°C (≤25°F), ice crystals form in the blood, causing mechanical damage, inflammation, thrombosis, and cellular death. Lower temperatures, higher wind speeds, and moisture exacerbate the process. The frozen part or area should not be rewarmed unless the patient can remain in a warm environment; repeated freeze/thaw cycles cause further injury. Treatment involves rapid rewarming in a warm, circulating water bath 37°C to 39°C (99°F-102°F) or, if this is not possible, then contact with another human body. Thrombolytics show promise in the early treatment of frostbite. In the field, the depth and severity of the injury can be determined with laser Doppler ultrasound devices or thermography. In hospital settings, bone scintigraphy with single-photon emission computed tomography (SPECT) 2 to 4 days postinjury provides detailed information on the depth of the injury. Prevention is focused primarily on covering exposed skin with proper clothing and minimizing exposure to wind and moisture. The Generation III Extended Cold Weather Clothing System is an interchangeable 12-piece clothing ensemble designed for low temperatures and is compatible with other military systems. The Extreme Cold Vapor Barrier Boot has outer and inner layers composed of seamless rubber with wool insulation between, rated for low temperatures. The Generation 3 Modular Glove System consists of 11 different gloves and mitts with design features that assist in enhancing grip, aid in the use of mobile devices, and allow shooting firearms. Besides clothing, physical activity also increases body heat, reducing the risk of frostbite.

Keywords: temperature; wind; moisture; thrombolytics; laser Doppler ultrasound; bone scintigraphy; computed tolography; Extended Cold Weather Clothing System; Extreme Cold Vapor Barrier Boot; Generation 3 Modular Glove System; physical activity

The Use of Tranexamic Acid in Tactical Combat Casualty Care: TCCC Proposed Change 20-02

Fall 2020

Drew B, Auten JD, Cap AP, Deaton TG, Donham B, Dorlac WC, DuBose JJ, Fisher AD, Ginn AJ, Hancock J, Holcomb JB, Knight J, Koerner AK, Littlejohn LF, Martin MJ, Morey JK, Morrison J, Schreiber MA, Spinella PC, Walrath B, Butler FK. 20(3). 36 - 43. (Journal Article)

Abstract

The literature continues to provide strong support for the early use of tranexamic acid (TXA) in severely injured trauma patients. Questions persist, however, regarding the optimal medical and tactical/logistical use, timing, and dose of this medication, both from the published TXA literature and from the TCCC user community. The use of TXA has been explored outside of trauma, new dosing strategies have been pursued, and expansion of retrospective use data has grown as well. These questions emphasize the need for a reexamination of TXA by the CoTCCC. The most significant updates to the TCCC Guidelines are (i) including significant traumatic brain injury (TBI) as an indication for TXA, (ii) changing the dosing protocol to a single 2g IV/IO administration, and (iii) recommending TXA administration via slow IV/IO push.

Keywords: TXA; tranexamic acid; hemorrhage; hemostatics; antifibrinolytics; hemorrhagic shock; traumatic brain injury; traumatic injuries

Ketamine Administration by Special Operations Medical Personnel During Training Mishaps

Fall 2020

Fisher AD, Schwartz DS, Petersen CD, Meyer SE, Thielemann JN, Redman TT, Rush SC. 20(3). 81 - 86. (Journal Article)

Abstract

Background: Opioids can have adverse effects on casualties in hemorrhagic shock. In 2014, the Committee on Tactical Combat Casualty Care (CoTCCC) recommended the use of ketamine at the point of injury (POI). Despite these recommendations the adherence is moderate at best. Poor use may stem from a lack of access to use ketamine during training. The United States Special Operations Command (USSOCOM) is often in a unique position, they maintain narcotics for use during all training events and operations. The goal of this work is to demonstrate that ketamine is safe and effective in both training and operational environments. Methods: This was a retrospective, observational performance improvement project within United States Special Operations Command and Air Combat Command that included the US Army's 75th Ranger Regiment, 160th Special Operations Aviation Regiment, and US Air Force Pararescue. Descriptive statistics were used to calculate the doses per administration to include the interquartile range (IQR), standard deviation (SD) and the range of likely doses using a 95% confidence interval (CI). A Wilcoxon signed-rank test was used to compare the mean pre-ketamine pain scores to the mean post-ketamine on a 0-to-10 pain scale. Results: From July 2010 to October 2017, there was a total of 34 patients; all were male. A total of 22 (64.7%) received intravenous ketamine and 12 (35.3%) received intramuscular ketamine and 8 (23.5%) received intranasal ketamine. The mean number of ketamine doses via all routes administered to patients was 1.88 (SD 1.094) and the mean total dose of all ketamine administration was 90.29mg (95% CI, 70.09-110.49). The mean initial dose of all ketamine administration was 47.35mg (95% CI, 38.52-56.18). The median preketamine pain scale for casualties was noted to be 8.0 (IQR 3) and the median post-ketamine pain scale was 0.0 (IQR 3). Conclusion: Ketamine appears to be safe and effective for use during military training accidents. Military units should consider allowing their medics to carry and use as needed.

Keywords: ketamine; opioids; training; war-related injuries; analgesia

Far Forward Gaps in Hemorrhagic Shock and Prolonged Field Care: An Update of ALM Fluid Therapy for Field Use

Fall 2020

Dobson GP, Letson HL. 20(3). 128 - 134. (Journal Article)

Abstract

Future expeditionary missions are expected to occur in more remote austere environments where combat medics and casualties may have to wait up to 7 days before resupply or safe evacuation. Currently, there is no effective fluid therapy for hemorrhagic shock (HS) at the point-of-injury and continuum-of-care over this extended period. We have been developing a small-volume IV or IO ALM therapy for noncompressible HS and have shown in preclinical models that it extends survival to 3 days, reduces abdominal bleeding by 60%, blunts inflammation, corrects coagulopathy, preserves platelet function, and prevents immunodeficiency. The ALM-survival phenotype is associated with an upregulation of the master genes of metabolism and mitochrondrial biogenesis in heart and brain and a downregulation in the periphery. Future translational studies will investigate the timing and nature of the "switch" and extend survival to 7 days. We will also discuss some of the controversies of ALM resuscitation in pigs, present our Systems Hypothesis of Trauma (SHOT), and discuss future clinical safety trials before field use.

Keywords: hemorrhage; trauma; survival; genetics; metabolism; inflammation; military medicine; resuscitation

Joint Trauma System Clinical Practice Guideline: Austere Resuscitative and Surgical Care - 30 October 2019

Summer 2020

Anonymous A. 20(2). 25 - 42. (Journal Article)

Abstract

Keywords:

Joint Trauma System Clinical Practice Guideline: Global Snake Envenomation Management

Summer 2020

Anonymous A. 20(2). 43 - 74. (Journal Article)

Abstract

Keywords:

Be in the Know: Dietary Supplements for Cognitive Performance

Summer 2020

Crawford C, Deuster PA. 20(2). 132 - 135. (Journal Article)

Abstract

Dietary supplements promoted for brain health and enhanced cognitive performance are becoming increasingly popular. Special Operations Forces (SOF) is likely a prime target for this market as they strive to continually optimize and then sustain their high level of performance at all times. When a dietary supplement hits the market, it is considered safe until it is proven otherwise; yet the majority have not been analyzed for quality or tested for safety. The authors describe issues related to products marketed for brain health and cognitive enhancement and focus on products brought to our attention by the operational communities. The overwhelming majority of product labels were found to be misbranded and some were found to contain prohibited ingredients and drugs. The problematic ingredients in these products are introduced. The Operation Supplement Safety scorecard algorithm is demonstrated as a tool to quickly screen a product for potential safety; it can be used in real-time when considering the use of any dietary supplement product. These resources are available to help SOF medical assets evaluate whether a product's claims may be deceiving and potentially harmful to the health or career of Operators.

Keywords: consumer product safety; decision aid; dietary supplements; education; mental processes

Freeze Dried Plasma Administration Within the Department of Defense Trauma Registry

Spring 2020

Cuenca CM, Chamy G, Schauer SG. 20(1). 43 - 45. (Journal Article)

Abstract

Hemorrhage is common among the combat injured, and plasma plays a vital role in blood product resuscitation. Regarding freeze dried plasma (FDP), US forces have had limited access to this product compared with other countries. In 2018, the US Food and Drug Administration provided emergency authorization for Department of Defense (DoD) use through the newly congressionally directed military use pathway. We describe the documented uses of FDP by US forces by performing a secondary analysis of two previously described datasets from the DoD Trauma Registry. In 11 identified cases, the median age was 28; cases were most frequently male, part of Operation Enduring Freedom, with US military affiliation, and injured by explosive or gunshot wound. The median injury severity score was 21; most did not receive a massive transfusion. Most survived to hospital discharge. Ongoing surveillance is warranted to optimize the implementation of FDP into military prehospital guidelines, training, and doctrine.

Keywords: freeze dried; plasma; combat; military

Advanced Resuscitative Care in Tactical Combat Casualty Care: TCCC Guidelines Change 18-01:14 October 2018

Winter 2018

Butler FK, Holcomb JB, Shackelford SA, Barbabella S, Bailey JA, Baker JB, Cap AP, Conklin CC, Cunningham CW, Davis MS, DeLellis SM, Dorlac WC, DuBose JJ, Eastridge BJ, Fisher AD, Glasser JJ, Gurney JM, Jenkins DA, Johannigman J, King DR, Kotwal RS, Littlejohn LF, Mabry RL, Martin MJ, Miles EA, Montgomery HR, Northern DM, O'Connor KC, Rasmussen TE, Riesberg JC, Spinella PC, Stockinger Z, Strandenes G, Via DK, Weber MA. 18(4). 37 - 55. (Journal Article)

Abstract

TCCC has previously recommended interventions that can effectively prevent 4 of the top 5 causes of prehospital preventable death in combat casualties-extremity hemorrhage, junctional hemorrhage, airway obstruction, and tension pneumothorax- and deaths from these causes have been markedly reduced in US combat casualties. Noncompressible torso hemorrhage (NCTH) is the last remaining major cause of preventable death on the battlefield and often causes death within 30 minutes of wounding. Increased use of whole blood, including the capability for massive transfusion, if indicated, has the potential to increase survival in casualties with either thoracic and/or abdominopelvic hemorrhage. Additionally, Zone 1 Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) can provide temporary control of bleeding in the abdomen and pelvis and improve hemodynamics in casualties who may be approaching traumatic cardiac arrest as a result of hemorrhagic shock. Together, these two interventions are designated Advanced Resuscitative Care (ARC) and may enable casualties with severe NCTH to survive long enough to reach the care of a surgeon. Although Special Operations units are now using whole blood far-forward, this capability is not routinely present in other US combat units at this point in time. REBOA is not envisioned as care that could be accomplished by a unit medic working out of his or her aid bag. This intervention should be undertaken only by designated teams of advanced combat medical personnel with special training and equipment.

Keywords: Advanced Resuscitative Care; Committee on Emergency Casualty Care; guidelines

Differences in Stress Shoot Performance Among Special Forces Operators Who Participate in a Human Performance Program Versus Those Who Do Not

Winter 2018

Canada DM, Dawes JJ, Lindsay KG, Elder C, Goldberg P, Bartley N, Werth K, Bricker D, Fischer T. 18(4). 64 - 68. (Journal Article)

Abstract

Background: The purpose of this investigation was to determine if Army Special Operation Forces (ARSOF) Operators who participate in the Tactical Human Optimization, Rapid Rehabilitation and Reconditioning program perform significantly better on a simulated stress shoot scenario than ARSOF Operators who do not participate in the program. Methods: Deidentified archival data from 64 male ARSOF Operators (mean ± standard deviation: age, 31.1 ± 4.96 years; SOF experience, 3.44 ± 4.10 years) who participated in the Special Forces Advanced Urban Combat stress shoot were assessed to determine if differences in performance existed between program users (n = 25) and nonusers (n = 39). A series of bootstrapped analyses of variance in conjunction with effect-size calculations was conducted to determine if significant mean score differences existed between users and nonusers on raw and total course completion times, high-value target acquisition (positive identification time), and penalties accrued. Results: Small to medium effect sizes were observed between users and nonusers in raw time, penalties, and total time. Although there were no significant differences between users and nonusers, there was less variation in raw time and total time in users compared with nonusers. Conclusion: Our findings becomes a question of practical versus statistical significance, because less performance variability while under physical and psychological duress could be life saving for ARSOF Operators.

Keywords: Tactical Human Optimization; Rapid Rehabilitation and Reconditioning program; human performance; stress shoot; duress

Willingness of Emergency Medical Services Professionals to Respond to an Active Shooter Incident

Winter 2018

Chovaz M, Patel RV, March JA, Taylor SE, Brewer KL. 18(4). 82 - 86. (Journal Article)

Abstract

Background: Historically, staging of civilian emergency medical services (EMS) during an active shooter incident was in the cold zone while these professionals awaited the scene to be completely secured by multiple waves of law enforcement. This delay in EMS response has led to the development of a more effective method: the Rescue Task Force (RTF). The RTF concept has the second wave of law enforcement escorting civilian EMS into the warm zone, thus decreasing EMS response time. To our knowledge, there are no data regarding the willingness of EMS professionals to enter a warm zone as part of an RTF. In this study, we assessed the willingness of EMS providers to respond to an active shooter incident as part of an RTF. Methods: A survey was distributed at an annual, educational EMS conference in North Carolina. The surveys were distributed on the first day of the conference at the beginning of a general session that focused on EMS stress and wellness. Total attendance was measured using identification badges and scanners on exiting the session. Data were assessed using χ2 analysis, as were associations between demographics of interest and willingness to respond under certain conditions. A p value < .01 indicated statistical significance. Results: The overall response rate was 76% (n = 391 of 515 session attendees). Most surveys were completed by paramedics (74%; n = 288 of 391). Most EMS professionals (75%; n = 293 of 391) stated they would respond to the given active shooter scenario as part of an RTF (escorted by the second wave of law enforcement) if they were given only ballistic gear. However, most EMS professionals (61%; n = 239 of 391) stated they would not respond if they were provided no ballistic gear and no firearm. Those with tactical or military training were more willing to respond with no ballistic gear and no firearm (49.6%; n = 68 of 137) versus those without such training (31%; n = 79 of 250; odds ratio, 2.2; 95% confidence interval, 1.4-3.3; p < .001). Conclusion: EMS professionals are willing to put themselves in harm's way by entering a warm zone if they are simply provided the proper training and ballistic equipment.

Keywords: emergency medical services; EMS; active shooter incident; Rescue Task Force

Comparison of Scapular Manipulation With External Rotation Method of Reduction of Acute Anterior Shoulder Dislocation for Sedation Requirements and Success Rates

Fall 2018

Adhikari S, Koirala P, Kafle D. 18(3). 34 - 37. (Journal Article)

Abstract

Background: Anterior shoulder dislocation is a common sports-related musculoskeletal injury. Various methods have been described for reduction of the dislocation. A method that requires less sedation without compromising the success rate is likely to be highly useful in austere and prehospital settings. This study compares scapular manipulation with external rotation method for requirement of sedation and success rates. Methods: Forty-six patients with anterior shoulder dislocation were allocated alternatively to reduction using either scapular manipulation (SMM) or external rotation (ERM) techniques. The groups were compared for sedation requirements, pain scores, and success rates. Results: Reductions using SMM had fewer requirements for sedation (13% versus 39%; p < .05) and higher first-pass success rates (87% versus 61%; p < .05) as compared with ERM for anterior shoulder dislocation reduction. The numeric rating score of pain during reduction procedures was less in SMM (mean, 1.65 [standard deviation, 1.6]) than in ERM group (mean, 4.30 [standard deviation, 1.8]; p < .01). Conclusion: The SMM required less sedation and had higher first-pass success rates than ERM for reduction of anterior shoulder dislocation. The SMM is thus likely to be of advantage in resource-limited austere settings.

Keywords: shoulder reduction; scapular manipulation; external rotation

A Pilot Study of Four Intraosseous Blood Transfusion Strategies

Fall 2018

Auten JD, Mclean JB, Kemp JD, Roszko PJ, Fortner GA, Krepela AL, Walchak AC, Walker CM, Deaton TG, Fishback JE. 18(3). 50 - 56. (Journal Article)

Abstract

Background: Intraosseous (IO) access is used by military first responders administering fluids, blood, and medications. Current IO transfusion strategies include gravity, pressure bags, rapid transfusion devices, and manual push-pull through a three-way stopcock. In a swine model of hemorrhagic shock, we compared flow rates among four different IO blood transfusion strategies. Methods: Nine Yorkshire swine were placed under general anesthesia. We removed 20 to 25mL/kg of each animal's estimated blood volume using flow of gravity. IO access was obtained in the proximal humerus. We then autologously infused 10 to 15mL/kg of the animal's estimated blood volume through one of four randomly assigned treatment arms. Results: The average weight of the swine was 77.3kg (interquartile range, 72.7kg-88.8kg). Infusion rates were as follows: gravity, 5mL/min; Belmont rapid infuser, 31mL/min; single-site pressure bag, 78mL/min; double-site pressure bag, 103mL/min; and push-pull technique, 109mL/min. No pulmonary arterial fat emboli were noted. Conclusion: The optimal IO transfusion strategy for injured Servicemembers appears to be single-site transfusion with a 10mL to 20mL flush of normal saline, followed immediately by transfusion under a pressure bag. Further study, powered to detect differences in flow rate and clinical complications. is required.

Keywords: blood transfusion; operational medicine; intraosseous infusion; intraosseous transfusion; hemorrhagic shock

Implementation and Evaluation of a First-Responder Bleeding-Control Training Program in a Rural Police Department

Fall 2018

Reed JR, Carman MJ, Titch FJ, Kotwal RS. 18(3). 57 - 61. (Journal Article)

Abstract

Background: In the prehospital environment, nonmedical first responders are often the first to arrive on the scene of a traumatic event and must be prepared to provide initial care at the point of injury. In civilian communities, these nonmedical first responders often include law enforcement officers. Hemorrhage is a major cause of death in trauma, and many of these deaths occur in the prehospital environment; therefore, prehospital training efforts should be directed accordingly toward bleeding control. Methods: A bleeding control training program was implemented and evaluated in a rural police department in Pinehurst, North Carolina, from February to April 2017. A repeated measures observational study was conducted to evaluate the training program. Measured were self-efficacy (pre- and post-test), knowledge (pretest, post-test 1 [immediate], post-test 2 [at 4 weeks]), and limb-tourniquet application time (classroom, simulation exercise). Results: The study population was composed of 28 police officers (92.9% male) whose median age was 37 (interquartile range, 22-55) years. Mean self-efficacy scores, equating to user confidence and the decision to intervene, increased from pre- to post-training (34.54 [standard deviation (SD) 4.16] versus 35.62 [SD 4.17]; p = .042). In addition, mean knowledge test scores increased from pre- to immediately post-training (75.00 [SD 16.94] versus 85.83 [SD 11.00]; p = .006), as well as from preto 4 weeks post-training (75.00 [SD 16.94] versus 84.17 [SD 11.77]; p = .018). Lower limb-tourniquet application times were more rapid in the classroom than during the simulation exercise (23.06 seconds [SD 7.68] versus 31.91 seconds [SD 9.81]; p = .005). Conclusion: First-responder bleeding-control programs should be initiated and integrated at the local level throughout the Nation. Implementation and sustainment of such programs in police departments can save lives and enhance existing law enforcement efforts to protect and serve communities.

Keywords: bleeding control; first responder; hemorrhage; limb tourniquet; prehospital; trauma

Management of Suspected Tension Pneumothorax in Tactical Combat Casualty Care: TCCC Guidelines Change 17-02

Summer 2018

Butler FK, Holcomb JB, Shackelford SA, Montgomery HR, Anderson S, Cain JS, Champion HR, Cunningham CW, Dorlac WC, Drew B, Edwards K, Gandy JV, Glassberg E, Gurney JM, Harcke T, Jenkins DA, Johannigman J, Kheirabadi BS, Kotwal RS, Littlejohn LF, Martin MJ, Mazuchowski EL, Otten EJ, Polk T, Rhee P, Seery JM, Stockinger Z, Torrisi J, Yitzak A, Zafren K, Zietlow SP. 18(2). 19 - 35. (Journal Article)

Abstract

This change to the Tactical Combat Casualty Care (TCCC) Guidelines that updates the recommendations for management of suspected tension pneumothorax for combat casualties in the prehospital setting does the following things: (1) Continues the aggressive approach to suspecting and treating tension pneumothorax based on mechanism of injury and respiratory distress that TCCC has advocated for in the past, as opposed to waiting until shock develops as a result of the tension pneumothorax before treating. The new wording does, however, emphasize that shock and cardiac arrest may ensue if the tension pneumothorax is not treated promptly. (2) Adds additional emphasis to the importance of the current TCCC recommendation to perform needle decompression (NDC) on both sides of the chest on a combat casualty with torso trauma who suffers a traumatic cardiac arrest before reaching a medical treatment facility. (3) Adds a 10-gauge, 3.25-in needle/ catheter unit as an alternative to the previously recommended 14-gauge, 3.25-in needle/catheter unit as recommended devices for needle decompression. (4) Designates the location at which NDC should be performed as either the lateral site (fifth intercostal space [ICS] at the anterior axillary line [AAL]) or the anterior site (second ICS at the midclavicular line [MCL]). For the reasons enumerated in the body of the change report, participants on the 14 December 2017 TCCC Working Group teleconference favored including both potential sites for NDC without specifying a preferred site. (5) Adds two key elements to the description of the NDC procedure: insert the needle/ catheter unit at a perpendicular angle to the chest wall all the way to the hub, then hold the needle/catheter unit in place for 5 to 10 seconds before removing the needle in order to allow for full decompression of the pleural space to occur. (6) Defines what constitutes a successful NDC, using specific metrics such as: an observed hiss of air escaping from the chest during the NDC procedure; a decrease in respiratory distress; an increase in hemoglobin oxygen saturation; and/or an improvement in signs of shock that may be present. (7) Recommends that only two needle decompressions be attempted before continuing on to the "Circulation" portion of the TCCC Guidelines. After two NDCs have been performed, the combat medical provider should proceed to the fourth element in the "MARCH" algorithm and evaluate/treat the casualty for shock as outlined in the Circulation section of the TCCC Guidelines. Eastridge's landmark 2012 report documented that noncompressible hemorrhage caused many more combat fatalities than tension pneumothorax.1 Since the manifestations of hemorrhagic shock and shock from tension pneumothorax may be similar, the TCCC Guidelines now recommend proceeding to treatment for hemorrhagic shock (when present) after two NDCs have been performed. (8) Adds a paragraph to the end of the Circulation section of the TCCC Guidelines that calls for consideration of untreated tension pneumothorax as a potential cause for shock that has not responded to fluid resuscitation. This is an important aspect of treating shock in combat casualties that was not presently addressed in the TCCC Guidelines. (9) Adds finger thoracostomy (simple thoracostomy) and chest tubes as additional treatment options to treat suspected tension pneumothorax when further treatment is deemed necessary after two unsuccessful NDC attempts-if the combat medical provider has the skills, experience, and authorizations to perform these advanced interventions and the casualty is in shock. These two more invasive procedures are recommended only when the casualty is in refractory shock, not as the initial treatment.

Keywords: guidelines; tension pneumothorax; Tactical Combat Casualty Care

Evaluation of the US Army Special Forces Tactical Human Optimization, Rapid Rehabilitation, and Reconditioning Program

Summer 2018

Grier T, Anderson MK, Depenbrock P, Eiserman R, Nindl BC, Jones BH. 18(2). 42 - 48. (Journal Article)

Abstract

Background: We sought to assess the rehabilitation process, training, performance, and injury rates among those participating and not participating in the Tactical Human Optimization, Rapid Rehabilitation, and Reconditioning (THOR3) program and determine injury risk factors. Methods: A survey inquiring about personal characteristics, injuries, physical performance, and THOR3 participation during the previous 12 months was administered to Army Special Operations Forces (SOF) Soldiers. Based on responses to physical training, Soldiers were categorized into three groups: a traditional physical training (TPT) group, a cross-training (CT) group, and a THOR3 group. To identify potential injury risk factors, risk ratios and 95% confidence intervals (95% CIs) were calculated. Backward- stepping multivariable logistic regression models were used to assess key factors associated with injury risk. Results: The survey was completed by 328 male Soldiers. Most of the Soldiers (62%) who scheduled an appointment with the physical therapist were seen within 1 day. Self-reported injury rates for the TPT, CT, and THOR3 groups were 70%, 52%, and 48%, respectively. When controlling for personal characteristics, unit training, and fitness, the TPT group had a marginally higher risk of being injured than the THOR3 group (odds ratio [OR], 2.72; 95% CI, 0.86-8.59; p = .09). Soldiers who did not perform any unit resistance training (ORnone/90-160 min, 3.62; 95% CI, 1.05-12.53; p = .04) or the greatest amount of resistance training (OR>160 min/90-160 min, 3.44; 95% CI, 1.64-7.20; p < .01) were more likely to experience an injury than the moderate-resistance training group. Conclusion: THOR3 appears to offer human performance optimization/injury prevention advantages over other SOF human performance programs.

Keywords: THOR3; physical fitness; physical training; musculoskeletal; athletic performance; injury

Survey of Casualty Evacuation Missions Conducted by the 160th Special Operations Aviation Regiment During the Afghanistan Conflict

Summer 2018

Redman TT, Mayberry KE, Mora AG, Benedict BA, Ross EM, Mapp JG, Kotwal RS. 18(2). 79 - 85. (Journal Article)

Abstract

Background: Historically, documentation of prehospital combat casualty care has been relatively nonexistent. Without documentation, performance improvement of prehospital care and evacuation through data collection, consolidation, and scientific analyses cannot be adequately accomplished. During recent conflicts, prehospital documentation has received increased attention for point-of-injury care as well as for care provided en route on medical evacuation platforms. However, documentation on casualty evacuation (CASEVAC) platforms is still lacking. Thus, a CASEVAC dataset was developed and maintained by the 160th Special Operations Aviation Regiment (SOAR), a nonmedical, rotary-wing aviation unit, to evaluate and review CASEVAC missions conducted by their organization. Methods: A retrospective review and descriptive analysis were performed on data from all documented CASEVAC missions conducted in Afghanistan by the 160th SOAR from January 2008 to May 2015. Documentation of care was originally performed in a narrative after-action review (AAR) format. Unclassified, nonpersonally identifiable data were extracted and transferred from these AARs into a database for detailed analysis. Data points included demographics, flight time, provider number and type, injury and outcome details, and medical interventions provided by ground forces and CASEVAC personnel. Results: There were 227 patients transported during 129 CASEVAC missions conducted by the 160th SOAR. Three patients had unavailable data, four had unknown injuries or illnesses, and eight were military working dogs. Remaining were 207 trauma casualties (96%) and five medical patients (2%). The mean and median times of flight from the injury scene to hospital arrival were less than 20 minutes. Of trauma casualties, most were male US and coalition forces (n = 178; 86%). From this population, injuries to the extremities (n = 139; 67%) were seen most commonly. The primary mechanisms of injury were gunshot wound (n = 89; 43%) and blast injury (n = 82; 40%). The survival rate was 85% (n = 176) for those who incurred trauma. Of those who did not survive, most died before reaching surgical care (26 of 31; 84%). Conclusion: Performance improvement efforts directed toward prehospital combat casualty care can ameliorate survival on the battlefield. Because documentation of care is essential for conducting performance improvement, medical and nonmedical units must dedicate time and efforts accordingly. Capturing and analyzing data from combat missions can help refine tactics, techniques, and procedures and more accurately define wartime personnel, training, and equipment requirements. This study is an example of how performance improvement can be initiated by a nonmedical unit conducting CASEVAC missions.

Keywords: casualty evacuations; CASEVAC; en route care; Tactical Combat Casualty Care; TCCC

Laboratory Model of a Collapsible Tube to Develop Bleeding Control Interventions

Spring 2018

Griffin LV, Kragh JF, Dubick MA. 18(1). 47 - 52. (Journal Article)

Abstract

Background: To develop knowledge of mechanical control of bleeding in first aid, a laboratory model was set up to simulate flow through a blood vessel. A collapsible tube was used to mimic an artery in two experiments to determine (1) the extent of volumetric flow reduction caused by increases in the degree of compression of the vessel and (2) the extent of flow reduction caused by increases in the length of compression. Methods: Water was used in vertical tubing. Gravity applied a pressure gradient of about 100mmHg to cause flow. A silicone tube (10mm-diameter lumen [the inner opening], 1mm-thick wall, 150mm length) was used. Tests of no compression of the external wall constituted the control group for both experiments. For all groups, flow volume was sampled over a period of time, and six samples were averaged. In both experiments, the study group consisted of tests with compression that was measured as the reduced area of the luminal cross section. In the first experiment, six groups with luminal area reductions of 0% (control), 74%, 81%, 91%, 94%, and 97% were tested. In the second experiment at 74% luminal area reduction, the three lengths of compression were 5mm, 20mm, and 70mm. The measured data were compared with calculated data by applying established mathematical equations. Results: In the first experiment, flow decreased with decreasing area due to luminal compression, but the association was a parabolic curve such that 94% or greater reduction in luminal area was required to reduce flow by greater than 50%. A reduction in luminal area of 97% reduced flow by 95%. In the second experiment, mean flow rates were not significantly different among the three lengths of compression. Measured data and calculated data were in good agreement. Conclusions: Compared with an uncompressed vessel, volumetric flow of water through a single, unsupported collapsible tube in steady, nonpulsatile conditions with compression applied to its external wall to produce a reduction in luminal area of 97% reduced flow by 95%. Flow was affected by the degree of compression but not by the length of compression.

Keywords: first aid/therapy, tourniquet; hemorrhage, prevention and control, bleeding control; biomechanics, collapsible tubes, steady flow, rheology, pres; models, theoretical

Ocular Injuries and Cultural Influences in Afghanistan During 5 Months of Operation Enduring Freedom

Spring 2018

Paz DA, Thomas KE, Primakov DG. 18(1). 77 - 80. (Journal Article)

Abstract

In support of Operation Enduring Freedom, American, North American Treaty Organization (NATO) Coalition, and Afghan forces worked together in training exercises and counterinsurgency operations. While serving at the NATO Role 3 Multinational Medical Unit, Kandahar, Afghanistan, numerous patients with explosive blast injuries (Coalition and Afghan security forces, and insurgents) were treated. A disparity was noted between the ocular injury patterns of US and Coalition forces in comparison with their Afghan counterparts, which were overwhelmingly influenced by the use, or lack thereof, of eye protection. Computed tomography imaging coupled, with a correlative clinical examination, demonstrated the spectrum of ocular injuries that can result from an explosive blast. Patient examination was performed by Navy radiologists and an ophthalmologist. A cultural analysis by was performed to understand why eye protection was not used, even if available to Afghan forces, by the injured patients in hope of bridging the gap between Afghan cultural differences and proper operational risk management of combat forces.

Keywords: ocular injury; culture; explosive blast injury

Resuscitative Endovascular Balloon Occlusion of the Aorta: Pushing Care Forward

Spring 2017

Teeter WA, Romagnoli AN, Glaser J, Fisher AD, Pasley JD, Scheele B, Hoehn M, Brenner ML. 17(1). 17 - 21. (Case Reports)

Abstract

Background: Resuscitative endovascular balloon occlusion of the aorta (REBOA), used to temporize noncompressible and junctional hemorrhage, may be deployable to the forward environment. Our hypothesis was that nonsurgeon physicians and high-level military medical technicians would be able to learn the theory and insertion of REBOA. Methods: US Army Special Operations Command medical personnel without prior endovascular experience were included. All participants received didactic instruction of the Basic Endovascular Skills for Trauma Course™ together, with individual evaluation of technical skills. A pretest and a posttest were administered to assess comprehension. Results: Four members of US Army Special Operations Command-two nonsurgeon physicians, one physician assistant, and one Special Operations Combat Medic-were included. REBOA procedural times moving from trial 1 to trial 6 decreased significantly from 186 ± 18.7 seconds to 83 ± 10.3 seconds (ρ < .0001). All participants demonstrated safe REBOA insertion and verbalized the indications for REBOA insertion and removal through all trials. All five procedural tasks were performed correctly by each participant. Comprehension and knowledge between the pretest and posttest improved significantly from 67.6 ± 7.3% to 81.3 ± 8.1% (ρ = .039). Conclusion: This study demonstrates that nonsurgeon and nonphysician providers can learn the steps required for REBOA after arterial access is established. Although insertion is relatively straightforward, the inability to gain arterial access percutaneously is prohibitive in providers without a surgical skillset and should be the focus of further training.

Keywords: REBOA; resuscitative endovascular balloon occlusion of the aorta; training; virtual reality simulation; junctional hemorrhage; noncompressable torso hemorrhage

Management of External Hemorrhage in Tactical Combat Casualty Care: The Adjunctive Use of XStat™ Compressed Hemostatic Sponges: TCCC Guidelines Change 15-03

Spring 2016

Sims K, Montgomery HR, Dituro P, Kheirabadi BS, Butler FK. 16(1). 19 - 28. (Journal Article)

Abstract

Exsanguination from wounds in the so-called junctional regions of the body (i.e., the neck, the axilla, and the groin) was responsible for 19% of the combat fatalities who died from potentially survivable wounds sustained in Afghanistan or Iraq during 2001 to 2011. The development of improved techniques and technology to manage junctional hemorrhage has been identified in the past as a high-priority item by the Committee on Tactical Combat Casualty Care (CoTCCC) and the Army Surgeon General's Dismounted Complex Blast Injury (DCBI) Task Force. Additionally, prehospital care providers have had limited options with which to manage hemorrhage resulting from deep, narrow-track, penetrating trauma. XStat™ is a new product recently approved by the US Food and Drug Administration as a hemostatic adjunct to aid in the control of bleeding from junctional wounds in the groin or axilla. XStat has now been recommended by the CoTCCC as another tool for the combat medical provider to use in the management of junctional hemorrhage. The evidence that supports adding XStat to the TCCC Guidelines for the treatment of external hemorrhage is summarized in this paper.

Keywords: hemorrhage, junctional; hemorrhage, external; hemostatic; tourniquets; TCCC Guideline; XStat™

Traumatic Brain Injury: Its Outcomes On High Altitude

Spring 2016

Ismailov RM, Lytle JM. 16(1). 67 - 69. (Editorial)

Abstract

Keywords:

Injuries And Footwear (Part 2): Minimalist Running Shoes

Spring 2016

Knapik JJ, Orr R, Pope R, Grier T. 16(1). 89 - 96. (Journal Article)

Abstract

This article defines minimalist running shoes and examines physiological, biomechanical, and injury rate differences when running in conventional versus minimalist running shoes. A minimalist shoe is one that provides "minimal interference with the natural movement of the foot, because of its high flexibility, low heel to toe drop, weight and stack height, and the absence of motion control and stability devices." Most studies indicate that running in minimalist shoes results in a lower physiological energy cost than running in conventional shoes, likely because of the lower weight of the minimalist shoe. Most individuals running in conventional shoes impact the ground heel first (rearfoot strike pattern), whereas most people running in minimalist shoes tend to strike with the front of the foot (forefoot strike pattern). The rate at which force is developed on ground impact (i.e., the loading rate) is generally higher when running in conventional versus minimalist shoes. Findings from studies that have looked at associations between injuries and foot strike patterns or injuries and loading rates are conflicting, so it is not clear if these factors influence injury rates; more research is needed. Better-designed prospective studies indicate that bone stress injuries and the overall injury incidence are higher in minimalist shoes during the early weeks (10-12 weeks) of transition to this type of footwear. Longer-term studies are needed to define injury rates once runners are fully transitioned to minimalist shoes. At least one longer-term minimalist-shoe investigation is ongoing and, hopefully, will be published soon.

Keywords: injuries, foot; footwear; shoes, minimalist; shoes, conventional; shoes, running

Management of Anaphylaxis in an Austere or Operational Environment

Winter 2014

Ellis BC, Brown SG. 14(4). 1 - 5. (Case Reports)

Abstract

We present a case report of a Special Operations Soldier who developed anaphylaxis as a consequence of a bee sting, resulting in compromise of the operation. We review the current literature as it relates to the pathophysiology of the disease process, its diagnosis, and its management. An evidence-based field treatment algorithm is suggested.

Keywords: anaphylaxis; anaphylactic shock; epinephrine; epinephrine infusion; review; remote; austere

Evaluation of NuStat®, a Novel Nonimpregnated Hemostatic Dressing, Compared With Combat Gauze™ in Severe Traumatic Porcine Hemorrhage Model

Winter 2014

Hillis GR, Yi CJ, Amrani DL, Akers TW, Schwartz RB, Wedmore I, McManus JG. 14(4). 41 - 47. (Journal Article)

Abstract

Background: Uncontrolled hemorrhage remains one of the most challenging problems facing emergency medical professionals and a leading cause of traumatic death in both battlefield and civilian environments. Survival is determined by the ability to rapidly control hemorrhage. Several commercially available topical adjunct agents have been shown to be effective in controlling hemorrhage, and one, Combat Gauze™ (CG), is used regularly on the battlefield and for civilian applications. However, recent literature reviews have concluded that no ideal topical agent exists for all injuries and scenarios. The authors compared a novel nonimpregnated dressing composed of cellulose and silica, NuStat® (NS), to CG in a lethal hemorrhagic groin injury. These dressings were selected for their commercial availability and design intended for control of massive hemorrhage. Methods: A complex penetrating femoral artery groin injury was made using a 5.5mm vascular punch followed by 45 seconds of uncontrolled hemorrhage in 15 swine. The hemostatic dressings were randomized using a random sequence generator and then assigned to the animals. Three minutes of manual pressure was applied with each agent after the free bleed. Hextend™ bolus (500mL) was subsequently rapidly infused using a standard pressure bag along with the addition of maintenance fluids to maintain blood pressure. Hemodynamic parameters were recorded every 10 minutes and additionally at critical time points defined in the protocol. Primary end points included immediate hemostasis upon release of manual pressure (T0), hemostasis at 60 minutes, and rebleeding during the 60-minute observation period. Results: NS was statistically superior to CG in a 5.5mm traumatic hemorrhage model at T0 for immediate hemostasis (ρ = .0475), duration of application time (ρ = .0093), use of resuscitative fluids (ρ = .0042) and additional blood loss after application (ρ = .0385). NS and CG were statistically equivalent for hemostasis at 60 minutes, rebleeding during the study, and the additional secondary metrics, although the trend indicated that in a larger sample size, NS could prove statistical superiority in selected categories. Conclusions: In this porcine model of uncontrolled hemorrhage, NS improved immediate hemorrhage control, stability, and use of fluid in a 60-minute severe porcine hemorrhage model. In this study, NS demonstrated equivalence to CG at achieving long-term hemostasis and the prevention of rebleed after application. NS was shown to be an efficacious choice for hemorrhage control in combat and civilian emergency medical service environments.

Keywords: EMS; hemostatic dressing; hemorrhage, uncontrolled; hemorrhage, severe; traumatic injuries; NuStat; NS; CG; silica; bamboo; cellulose; Combat Gauze™; kaolin

The Use of Dexamethasone in Support of High-Altitude Ground Operations and Physical Performance: Review of the Literature

Winter 2014

O'Hara R, Serres J, Dodson W, Bruce W, Ordway J, Powell E, Wade M. 14(4). 53 - 58. (Journal Article)

Abstract

Objective: Military Special Operators (SOs) are exposed environmental conditions that can alter judgment and physical performance: uneven terrain, dryness of ambient air, reduction of air density, and a diminished partial pressure of oxygen. The primary purpose of this review was to determine the medical efficacy of dexamethasone as an intervention for the prevention and treatment of high-altitude illness. The secondary purpose was to determine its ability to maintain physical performance of SOs at high altitudes. Methods: A search of the literature from 1970 to 2014 was performed, locating 61 relevant articles, with 43 addressing the primary and secondary purposes of this literature review. Conclusions: The review indicates that dexamethasone is an effective prevention and treatment intervention for high-altitude illness. Commonly used dosages of either 2mg every 6 hours or 4mg every 12 hours can prevent high-altitude illnesses in adults. Currently in USSOCOM operations, there is an option to use 4mg every 6 hours (concurrently with acetazolamide 125mg bid) if ascending rapidly to or above 11,500 ft without time for acclimatization. Researchers also determined that acute exposure to high altitude, even in asymptomatic subjects, resulted in small cognitive deficits that could be reversed with dexamethasone. Dexamethasone may also help improve cognition and maximal aerobic capacity in SOs who are susceptible to high-altitude pulmonary edema.

Keywords: high altitude; mountain; performance; strength; endurance; physical; military; Special Operations

Needle Thoracentesis Decompression: Observations From Postmortem Computed Tomography and Autopsy

Winter 2013

Harcke HT, Mabry RL, Mazuchowski EL. 13(4). 53 - 58. (Journal Article)

Abstract

Background: Needle thoracentesis decompression (NTD) is a recommended emergency treatment for tension pneumothorax. Current doctrine recognizes two suitable sites: the second intercostal space in the midclavicular line and the fourth or fifth intercostal space in the anterior axillary line. Methods: A review was conducted of postmortem computed tomography and autopsy results in 16 cases where NTD was performed as an emergency procedure. Results: In 16 cases with 23 attempted procedures, the outcome was confirmed in 17 attempts. In 7 placements, the catheter was in the pleural cavity; in 7 placements, the catheter never entered the pleural cavity; and in 3 placements, cavity penetration was verified at autopsy even though the catheter was no longer in the cavity. Success was noted in 6 of 13 anterior attempts and 4 of 4 lateral attempts, for an overall success rate of 59% (10 of 17). In the remaining 6 attempted procedures, a catheter was noted in the soft tissue on imaging; however, presence or absence of pleural cavity penetration was equivocal. All placements were attempted in the combat environment; no information is available about specifically where or by whom. Conclusion: NTD via a lateral approach was more successful than that via an anterior approach, although it was used in fewer cases. This supports the revision of the Tactical Combat Casualty Care Guidelines specifying the lateral approach as an alternative to an anterior approach.

Keywords: needle thoracentesis decompression; Tactical Combat Casualty Care guidelines; tension pneumothorax

Point-of-Care Coagulation Testing for Trauma Patients in a Military Setting: A Prospective Study

Winter 2013

Cotte J, d'Aranda E, Chauvin V, Kaiser E, Meaudre E. 13(4). 59 - 62. (Journal Article)

Abstract

Background and Objective: Almost 50% of military trauma patients who need transfusions develop a coagulopathy. Immediately treating this coagulopathy improves the patient's prognosis. Field military hospitals often lack laboratory devices needed to diagnose a clinically significant coagulopathy and have limited blood product resources such as plasma. Point-of-care (POC) devices for the measurement of prothrombin time (PT) are available and have been tested in a variety of situations, including hemorrhagic surgery. The authors compared a POC device, the Coaguchek XS Pro (F. Hoffmann-La Roche Ltd., Basel, Switzerland), with laboratory measures for determining the PT in military trauma patients in a field hospital. Methods: This single-center prospective study was designed to compare POC coagulation monitoring with traditional laboratory testing. It was conducted at the French military hospital located at Kabul International Airport. All patients with trauma injuries resulting from war operations were included. A blood sample was drawn immediately on admission. PT was determined both in the laboratory and with use of the Coaguchek XS pro. Results: Forty patients with war trauma were enrolled during a 3-month period. The authors recorded 69 measurements. The two methods were correlated with a correlation coefficient of 0.78 (ρ < .001). The Bland- Altman plot showed a mean difference of 5.8% (95% confidence interval -14.9% to 26.6%). Using a PT cutoff of 60%, POC had a sensitivity of 77.1% and a specificity of 94.1%. Results from POC PT measurement were available within a mean of 25.8 minutes before laboratory measures. Conclusions: The Coaguchek XS Pro device can be used successfully in an austere environment without compromising its performance.

Keywords: point-of-care; coagulation; prothrombin time; military trauma

Preparing for Operations in a Resource-Depleted and/or Extended Evacuation Environment

Fall 2013

Corey G, Lafayette T. 13(3). 74 - 80. (Journal Article)

Abstract

The wars in Afghanistan and Iraq are the only conflicts to which many medics have ever been exposed. These mature theaters have robust medical systems that ensure rapid access to full-spectrum medical care for all combat-wounded and medically injured personnel. As current conflicts draw to a close, U.S. medics may be deployed to environments that will require the ability to stabilize casualties for longer than 1 hour. Historical mission analysis reveals the need to review skills that have not been emphasized during upgrade and predeployment training. This unit's preparation for the extended care environment can be accomplished using a 4-point approach: (1) review of specific long-term skills training, (2) an extended care lab that reviews extended care skills and then lets the medic practice in a real-time scenario, (3) introduction to the HITMAN mnemonic tool, which helps identify and address patient needs, and (4) teleconsultation.

Keywords: extended care; austere environments; long-term skills training; teleconsultation

Management of Open Pneumothorax in Tactical Combat Casualty Care: TCCC Guidelines Change 13-02

Fall 2013

Butler FK, DuBose JJ, Otten EJ, Bennett DR, Gerhardt RT, Kheirabadi BS, Gross K, Cap AP, Littlejohn LF, Edgar EP, Shackelford SA, Blackbourne LH, Kotwal RS, Holcomb JB, Bailey JA. 13(3). 81 - 86. (Journal Article)

Abstract

During the recent United States Central Command (USCENTCOM) and Joint Trauma System (JTS) assessment of prehospital trauma care in Afghanistan, the deployed director of the Joint Theater Trauma System (JTTS), CAPT Donald R. Bennett, questioned why TCCC recommends treating a nonlethal injury (open pneumothorax) with an intervention (a nonvented chest seal) that could produce a lethal condition (tension pneumothorax). New research from the U.S. Army Institute of Surgical Research (USAISR) has found that, in a model of open pneumothorax treated with a chest seal in which increments of air were added to the pleural space to simulate an air leak from an injured lung, use of a vented chest seal prevented the subsequent development of a tension pneumothorax, whereas use of a nonvented chest seal did not. The updated TCCC Guideline for the battlefield management of open pneumothorax is: "All open and/ or sucking chest wounds should be treated by immediately applying a vented chest seal to cover the defect. If a vented chest seal is not available, use a non-vented chest seal. Monitor the casualty for the potential development of a subsequent tension pneumothorax. If the casualty develops increasing hypoxia, respiratory distress, or hypotension and a tension pneumothorax is suspected, treat by burping or removing the dressing or by needle decompression." This recommendation was approved by the required two-thirds majority of the Committee on TCCC in June 2013.

Keywords: pneumothorax; chest seal; TCCC Guideline

No Slackers in Tourniquet Use to Stop Bleeding

Summer 2013

Polston RW, Clumpner BR, Kragh JF, Jones JA, Dubick MA, Billings S. 13(2). 12 - 19. (Journal Article)

Abstract

Background: Tourniquets on casualties in war have been loose in 4%-9% of uses, and such slack risks death from uncontrolled bleeding. A tourniquet evidence gap persists if there is a mechanical slack-performance association. Objective: The purpose of the present study was to determine the results of tourniquet use with slack in the strap versus no slack before windlass turning, in order to develop best practices. Methods: The authors used a tourniquet manikin 254 times to measure tourniquet effectiveness, windlass turns, time to stop bleeding, and blood volume lost at 5 degrees of strap slack (0mm, 25mm, 50mm, 100mm, and 200mm maximum). Results: When comparing no slack (0mm) to slack (any positive amount), there were increases with slack in windlass turns (ρ < .0001, 3-fold), time to stop bleeding (ρ < .0001, 2-fold), and blood volume lost (ρ < .0001, 2-fold). When comparing no slack to 200mm slack, the median results showed an increase in slack for windlass turns (ρ < .0001), time to stop bleeding (ρ < .0001), and blood volume lost (ρ < .0001). Conclusions: Any slack presence in the strap impaired tourniquet performance. More slack had worse results. Trainers can now instruct tourniquet users with concrete guidance.

Keywords: hemorrhage; first aid; trauma; damage control; resuscitation

Dengue Infections

Summer 2013

Burnett MW. 13(2). 64 - 68. (Journal Article)

Abstract

Background: Dengue fever is one of the most common mosquito-borne viral illnesses in the world. It is usually transmitted to humans through the bite of an infected Aedes aegypti or Aedes albopictus mosquito. Dengue infections are caused by four antigenically distinct but closely related viruses (DEN 1-4). Infection with any one of the viruses is thought to provide lifetime immunity to future infections from the same virus but only short-term cross-immunity to the other types, leading to the possibility of secondary infections. Dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), more severe types of dengue infections, sometimes result when an individual is subsequently infected with a second virus serotype during their lifetime. The most commonly accepted theory for the development of these more severe dengue infections is that of antibody-dependent enhancement, although other factors likely play a role. Infections complicated by DHF/DSS in areas where dengue is endemic are most often seen in the later half of the first year of life, when waning maternal antibodies may enhance the development of a more severe infection, and in young school-age children experiencing secondary infections. Widespread infections are most commonly seen during the rainy season of endemic areas when the breeding habitat of the Aedes mosquito is most favorable.

Keywords: dengue hemorrhagic fever; dengue shock syndrome; mosquito-borne viral illness