How Asymptomatic Transmission Influences Mitigation and Suppression Strategies during a Pandemic.

Asymptomatic transmission complicates any public health strategies to combat a pandemic, which proved especially accurate in the case of COVID-19. Although asymptomatic cases are not unique to COVID-19, the high asymptomatic case rate raised many problems for developing effective public health interventions. The current modeling effort explored how asymptomatic transmission might impact pandemic responses in four key areas: isolation procedures, changes in reproduction rate, the potential for reduced transmission from asymptomatic cases, and social adherence to public health measures. A high rate of asymptomatic cases effectively requires large-scale public health suppression and mitigation procedures given that quarantine procedures alone could not prevent an outbreak for a virus such as SARS-CoV-2. This problem only becomes worse without lowering the effective reproduction rate, and even assuming the potential for reduced transmission, any virus with a high degree of asymptomatic transmission will likely produce a pandemic. Finally, there is a concern that asymptomatic individuals will also refuse to adhere to public health guidance. Analyses indicate that, given certain assumptions, even half of the population adhering to public health guidance could reduce the peak and flatten the curve by over 90%. Taken together, these analyses highlight the importance of taking asymptomatic cases into account when modeling viral spread and developing public health intervention strategies.

Department of Defense positions on alternative uses of hyperbaric oxygen therapy.

Hyperbaric oxygen therapy is an existing and approved treatment to address multiple medical conditions, including decompression sickness, air or gas embolism, carbon monoxide poisoning, and profound blood loss when transfusion cannot be accomplished. However, recent efforts have emerged to promote hyperbaric oxygen therapy for other purposes. The most controversial applications have been utilizing this therapy as a treatment for mild traumatic brain injury and post-traumatic stress disorder. As evidence accumulates and the debate continues about whether published studies have satisfied the threshold of clinical significance, a common issue is raised regarding current clinical practices and health insurance coverage as allowed or recommended by the Department of Defense and other federal agencies. This review describes the current federal policies regarding medical insurance issues for providers and clinical practice guidelines as they pertain to alternative uses of hyperbaric oxygen therapy. First, the current policies are explored for what is reimbursable under federal insurance as approved clinical or research usages. Second, these policies are compared to the clinical practice guidelines to determine what might be clinical best practice versus exploratory research. Third, the evidence from government reports is reviewed as supporting documentation for these positions. As such, the current discussion addresses what can and cannot be covered under health insurance and where various federal health care organizations stand currently on using hyperbaric oxygen therapy as an alternative therapeutic technique. The primary goal is informing military healthcare practitioners and prospective patients about the treatment options available to them under current federal guidelines.

Treatment of Thoracic Trauma: Lessons From the Battlefield Adapted to All Austere Environments.

Severe thoracic trauma in the backcountry can be a formidable injury pattern to successfully treat. Traumatic open, pneumo-, and hemothoraces represent some of the most significant patterns for which advanced equipment and procedures may help leverage morbidity and mortality, particularly when evacuation is delayed and environmental conditions are extreme. This paper reviews the development of successful techniques for treating combat casualties with thoracic trauma, including the use of vented chest seals and the technique of needle thoracentesis. Recommendations are then given for applying this knowledge and skill set in the backcountry.

Vented chest seals for prevention of tension pneumothorax in a communicating pneumothorax.

BACKGROUND: Tension pneumothorax accounts for 3%-4% of combat casualties and 10% of civilian chest trauma. Air entering a wound via a communicating pneumothorax rather than by the trachea can result in respiratory arrest and death. In such cases, the Committee on Tactical Combat Casualty Care advocates the use of unvented chest seals to prevent respiratory compromise. OBJECTIVE: A comparison of three commercially available vented chest seals was undertaken to evaluate the efficacy of tension pneumothorax prevention after seal application. METHODS: A surgical thoracostomy was created and sealed by placing a shortened 10-mL syringe barrel (with plunger in place) into the wound. Tension pneumothorax was achieved via air introduction through a Cordis to a maximum volume of 50 mL/kg. A 20% drop in mean arterial pressure or a 20% increase in heart rate confirmed hemodynamic compromise. After evacuation, one of three vented chest seals (HyFin(®), n = 8; Sentinel(®), n = 8, SAM(®), n = 8) was applied. Air was injected to a maximum of 50 mL/kg twice, followed by a 10% autologous blood infusion, and finally, a third 50 mL/kg air bolus. Survivors completed all three interventions, and a 15-min recovery period. RESULTS: The introduction of 29.0 (±11.5) mL/kg of air resulted in tension physiology. All three seals effectively evacuated air and blood. Hemodynamic compromise failed to develop with a chest seal in place. CONCLUSIONS: HyFin(®), SAM(®), and Sentinel(®) vented chest seals are equally effective in evacuating blood and air in a communicating pneumothorax model. All three prevented tension pneumothorax formation after penetrating thoracic trauma.

Terlipressin with limited fluid resuscitation in a swine model of hemorrhage.

BACKGROUND: Principles of damage control resuscitation include minimizing intravenous fluid (IVF) administration while correcting perfusion pressure as quickly as possible. Recent studies have identified a potential advantage of vasopressin over catecholamines in traumatic shock. Terlipressin (TP) is a vasopressin analogue used to reverse certain shock etiologies in some European countries. STUDY OBJECTIVE: We evaluated three dosages of TP when combined with a limited colloid resuscitation strategy on mean arterial pressure (MAP) and lactatemia in a swine model of isolated hemorrhage. METHODS: Sixty anesthetized swine underwent intubation and severe hemorrhage. Subjects were randomized to one of four resuscitation groups: 4 mL/kg Hextend(®) (Hospira Inc, Lake Forest, IL) only, 3.75 µg/kg TP + Hextend, 7.5 µg/kg TP + Hextend, or 15 µg/kg TP + Hextend. MAP and heart rate were recorded every 5 min. Baseline and serial lactate values at 30-min intervals were recorded and compared. RESULTS: Subjects receiving 7.5 µg/kg TP had significantly higher MAPs at times t15 (p = 0.012), t20 (p = 0.004), t25 (p = 0.018), t30 (p = 0.032), t35 (p = 0.030), and t40 (p = 0.021). No statistically significant differences in lactate values between TP groups and controls were observed. CONCLUSION: Subjects receiving 7.5 µg/kg of TP demonstrated improved MAP within 10 min of administration. When combined with minimal IVF resuscitation, TP doses between 3.75 and 15 µg/kg do not elevate lactate levels in hemorrhaged swine.

Describing mRNA Vaccine Technology for a Military Audience.

INTRODUCTION: Vaccine technology has improved substantially since the first smallpox vaccine, developed more than 200 years ago. As technology improves, vaccines can be produced more safely and reliably for many different pathogens. A recent breakthrough saw the first full deployment of mRNA vaccines to fight a pandemic. Despite the technological and logistical feat of developing a viable vaccine in an abbreviated time frame, there have been many questions about this new approach to vaccine development. The current review will provide descriptions about different types of vaccines as well as answers to some common questions about mRNA vaccines. The purpose is to provide military medical professionals with the information needed to better convey the importance and function of these new vaccines to service members. MATERIALS AND METHODS: There were no explicit inclusion or exclusion criteria for articles describing mRNA vaccine technology. References included here were intended to illustrate important principles or empirical evidence in demonstrating the safety, efficacy, and function of mRNA vaccines. DISCUSSION: The review describes three different types of vaccines: whole-pathogen, subunit, and nucleic acid. Each vaccine type has different implications for the development and production of a vaccine line. For example, whole-pathogen and subunit vaccines often require growing significant amounts of the vaccine sample in laboratory before the material can be incorporated into the vaccine. Nucleic acid vaccines instead provide cells the opportunity to produce key proteins without needing to reproduce the virus and attenuate it in a laboratory setting. This approach has a notable advantage of speed in moving from genome sequencing to vaccine production, but it also creates some potential confusion. The discussion covers three questions with regard to this confusion. First, was the vaccine developed too quickly? Speed here is a byproduct of the new technology and unprecedented government interdepartmental cooperation. No steps were skipped in development or production. Second, does the vaccine modify DNA? No, the mRNA vaccines never enter the cell nucleus and therefore cannot modify DNA. The discussion clarifies how mRNA enters cells and produces the key proteins required to stimulate an immune system response. Third, how long will immunity last? Because mRNA vaccines are new, long-term immunity cannot be projected without significant further study. Still, the discussion does cover issues in determining vaccine efficacy in clinical laboratory trials versus field effectiveness in the real world. CONCLUSIONS AND FUTURE USES: These mRNA vaccines are the newest and most sophisticated defensive tool military medicine has against emerging biological threats. Evolving dangers, such as synthetic biology and engineered pathogens, further enhance the importance of having defensive countermeasures that can be rapidly deployed in response. Current evidence suggests high safety and effectiveness for a biological countermeasure, decades in the making, and military medical personnel should feel confident using and recommending this technology to ensure force health protection.

How the Five Principles of High Reliability Organizations Align with the Five Truths of Special Operations.

Special Operations medicine must provide highly reliable healthcare under intense and sometimes dangerous circumstances. In turn, it is important to understand the principles inherent to building a High Reliability Organization (HRO). These principles include (1) sensitivity to operations; (2) preoccupation with failure; (3) reluctance to simplify; (4) resilience; and (5) deference to expertise. Understanding them is crucial to turning good ideas into sound practical benefit in operational medicine. A prime teaching opportunity involves an interesting coincidence that occurred during the emergence of HROs. Specifically, United States Special Operations Command (USSOCOM) adopted five Special Operations Forces (SOF) Truths that contribute to success in Special Operations, including (1) humans are more important than hardware; (2) quality is better than quantity; (3) SOF cannot be mass produced; (4) competent SOF cannot be created after emergencies occur; and (5) most Special Operations require non-SOF support. These five Truths have more in common with the five HRO principles than merely quantity. They describe the same underlying ideas with a key focus on human performance in high-risk activities. As such, when presented alongside the five HRO principles, there is an opportunity to improve the overall health and performance of SOF personnel by integrating these principles across the range of Special Operations medicine from point of injury care to garrison human performance initiatives. The following discussion describes in greater detail the five HRO principles, the five SOF Truths, and how these similar ideas emerged as more than just a useful coincidence in illustrating the key concepts to produce high performance.

What a Special Operations Cognitive Assessment Should Look Like.

Special Operations organizations have recently demonstrated their commitment to enhanced cognitive functioning and improving brain health through the development of a Cognitive Domain. However, as this new enterprise becomes supported by more resources and personnel, a critical question involves what cognitive assessments should be conducted to evaluate cognitive functions. The assessment itself forms a crux in the Cognitive Domain that could mislead cognitive practitioners if not properly applied. Here, the discussion addresses the most important criteria to satisfy in the development of a Special Operations cognitive assessment, including operational relevance, optimization, and speed. Cognitive assessments in this domain must incorporate the following: (1) a task with clear operational relevance to ensure meaningful results, (2) no ceiling effects so that performance can support cognitive enhancement initiatives, and (3) the task itself should impose a minimal time requirement to avoid creating a substantial logistical burden. A dynamic threat assessment task supported by drift diffusion modeling can meet all requisite criteria, while also providing more insight into decision parameters of Special Operations personnel than any currently used test. The discussion concludes with a detailed description of this recommended cognitive assessment task, as well as the research and development steps needed to support its application.

Looking for more than hot air: how experimental design can enhance clinical evidence for hyperbaric oxygen therapy.

Hyperbaric oxygen therapy is emerging as a potential treatment for critical medical and psychological issues, including mild traumatic brain injury, traumatic brain injury, and post-traumatic stress disorder. Based on the promising results from numerous case studies, randomized clinical trials generated conflicting interpretations despite frequent improvements in patient symptoms. The primary debate concerns whether the therapeutic benefits could be attributed to placebo effects or sham conditions that actually induce a therapeutic state. In part, the contention has been exacerbated by experimental designs which could not properly account for extraneous variables, such as the potential for differing patient expectations to influence the outcome. The current discussion addresses five methodological challenges that complicate any determination of clinical significance due to experimental design. These challenges include: 1) not properly addressing or controlling patient expectations prior to the experimental sessions; 2) the challenge of experimental masking in clinical designs that require pressurized environments; 3) patient subjectivity in the primary dependent variables; 4) potential fluidity in patient symptoms or data, such as regression to the mean; and 5) the potential for nocebo effects to exaggerate treatment benefits by lowering performance expectations during pre-treatment assessments. Each factor provides an influential means by which placebo effects could complicate results and prevent the combined data from reaching a threshold of clinical significance. The discussion concludes with methodological best practices with which future research could minimize placebo effects and produce more conclusive results.

A Hierarchy of Medical Countermeasures Against Biological Threats.

INTRODUCTION: Emerging biological threats represent a serious challenge for force health protection (FHP). Against a novel biological threat, medical countermeasures are the first line of defense. However, as exposed by global pandemic conditions, there are significant complications when administering medical countermeasures against novel threats. One such limitation involved the lack of any guiding structure to discuss and deliberate upon the relative value of employing different countermeasures either alone or in tandem. For example, both personal protective equipment and prophylactic medication can provide some protection, but how are individual protections weighed against operational capabilities and FHP initiatives? The goal of this review is to provide a hierarchical organizing structure to the different medical countermeasures available in response to emerging biological threats. MATERIALS AND METHODS: This review used no explicit inclusion or exclusion criteria for its literature review. References are provided for illustrative purposes to represent different components of the medical hierarchy. DISCUSSION: The hierarchy presented here is organized around a resource-durability structure that functions as a push-pull mechanism. Specifically, lower levels of the hierarchy require more resources to sustain FHP conditions while also providing less durable protection. These countermeasures require continual reapplication, and so resources become conceived as much in time and effort to apply as in exhaustible supplies. Higher-order countermeasures require less resources investment as a single application can provide weeks, months, or years of protection. Moreover, higher-order protections are less likely to interfere with military operational capabilities, which further support their classification as superior countermeasures to sustain FHP. The five levels of the hierarchy are presented here as follows, organized from lowest to highest value as a medical countermeasure: (1) Sanitization, (2) personal protective equipment, (3) prophylaxis, (4) vaccines, and (5) optimized immune system. Rationale and descriptions identify how each higher-order countermeasure is superior to its lower-order counterparts while noting that optimizing FHP will likely require employing multiple countermeasures at different levels. The discussion concludes with an overview as to how different countermeasures were employed to various degrees during a novel global pandemic. CONCLUSIONS AND FUTURE USES: Identifying medical countermeasures is important to optimizing FHP. Different countermeasures have different advantages, and the hierarchy distinguishes between inferior and superior countermeasures through the push-pull style mechanism of resource-durability assessment. Future deployment and development should focus on superior countermeasures to maximize medical protections and operational readiness while understanding the relative value and complications inherent with different countermeasures.

Alternative Uses of Hyperbaric Oxygen Therapy in Military Medicine: Current Positions and Future Directions.

INTRODUCTION: Hyperbaric oxygen therapy (HBOT) is a commonly used treatment for a variety of medical issues, including more than a dozen currently approved uses. However, there are alternative proposed uses that have significant implications among an active duty military or veteran population as treatments for PTSD, mild traumatic brain injury (mTBI), and traumatic brain injury (TBI). These applications have seen a recent groundswell of support from the operator and veteran communities, raising the visibility of using HBOT for alternative applications. The current review will cover the existing evidence regarding alternative uses of HBOT in military medicine and provide several possibilities to explain the potential conflicting evidence from empirical results. MATERIALS AND METHODS: There were no inclusion or exclusion criteria for articles addressing currently approved HBOT uses as covered under the military health system. These references were provided for comparison and illustration as needed. For alternative HBOT uses, the review focuses explicitly upon three alternative uses in PTSD, mTBI, and TBI. The review addresses any piece of case study evidence, observational data, quasi-experimental design, or randomized-controlled trial that explored any or a combination of these issues within an active duty population, a veteran population, or a civilian population. RESULTS: The existing medical evidence does not support a consensus viewpoint for these alternative uses of HBOT. Based on the literature review, there are four competing positions to explain the lack of consistency among the empirical results. These possibilities are described in no particular order. First, an explanation suggests that the results are because of placebo effects. The combination of participant expectations and subjective symptom reporting creates the potential that reported improvements are because of placebo rather than casual mechanisms. Second, another position suggests that experiments have utilized sham conditions which induced therapeutic benefits. If sham conditions have actually been weakened active treatment conditions, rather than placebo controls, it could explain the lack of observed significant differences in randomized clinical trials. Third, there has been a substantial amount of heterogeneity both in the symptoms treated and the treatments applied. This heterogeneity could explain the inconsistency of the data and the difficulty in reaching a consensus viewpoint. Fourth, the HBOT treatments may actively treat some tangential medical issue the patient is having. The treatment would thus promote an environment of healing without directly treating either PTSD, mTBI, or TBI, and the reduction in orthogonal medical issues facilitates a pathway to recovery by reducing tangential medical problems. CONCLUSIONS: The mixed empirical evidence does not support recommending HBOT as a primary treatment for PTSD, mTBI, or TBI. If applied under the supervision of a licensed military medical professional, the consistently safe track record of HBOT should allow it to be considered as an alternative treatment for PTSD, mTBI, or TBI once primary treatment methods have failed to produce a benefit. However, the evidence does warrant further clinical investigation with particular emphasis on randomized clinical trials, better placebo controls, and a need to develop a consistent treatment protocol.

Head Wounds Received During Force-on-Force Training With Non-lethal Ammunition.

Close quarters combat training is designed to replicate the mental and physiological stressors of firing upon an adversary while in close proximity. One method to replicate combat stressors is to use non-lethal training ammunition specifically designed for force-on-force exercises. These rounds can be fired from slightly modified service-issued weapons and provide a pain sensation upon striking the opponent. The current investigation presents a case study of several injuries when these rounds impacted the head directly, which is a primary area of concern for safety issues. Most impacts produced initial swelling that reduced substantially within the first few hours. Approximately 24 hours later, the swelling disappeared entirely with a visible contusion near the impact center. Bruising would typically clear within a few days. However, another example produced sufficient bleeding to require intervention before continuing with the training exercises and sanguineous crust or scabbing rather than the typical contusion. Pain was minimal for all wounds after only several days, which aligns with previous research on pain from non-lethal training ammunition wounds. Based on the head wounds observed here, loss of eyesight is a realistic possibility. Eye protection should be a requisite across all force-on-force training exercises without exception. This case study documents some potential hazards of force-on-force training, but more importantly, it further highlights the need for medically informed training standards about engagement distances and personal protective equipment.

Comparison of ChitoFlex®, CELOX™, and QuikClot® in control of hemorrhage.

BACKGROUND: Exsanguinating extremity wounds remain the primary source of battlefield mortality. Operating forces employ three agents in Iraq: HemCon® (HemCon Medical Technologies, Inc., Portland, OR), QuikClot® (Z-Medica Corporation, Wallingford, CT), and CELOX™ (SAM Medical, Tualatin, OR). Anecdotal reports suggest that these agents are less useful on small entrance, linear-tract injuries. ChitoFlex® (HemCon Medical Technologies, Inc., Portland, OR) has been introduced but is untested. STUDY OBJECTIVES: To compare the equivalency of the ChitoFlex® dressing, QuikClot® ACS+™ dressing, CELOX™, and standard gauze in their effectiveness to control bleeding from non-cavitary groin wounds. METHODS: Forty-eight swine were randomly assigned to one of four treatment groups: standard gauze dressing (SD), ChitoFlex® dressing (CF), QuikClot® ACS+™ dressing (QC), and CELOX™ dressing (CX). A groin injury with limited vessel access was created in each animal. Subjects were resuscitated with 500 mL of hetastarch. The primary endpoint was 180-min survival. Secondary endpoints included total blood loss in mL/kg, incidence of re-bleeding, survival times among the animals that did not survive for 180 min, failure to achieve initial hemostasis, incidence of recurrent bleeding, time to initial re-bleeding, amount of re-bleeding, and mass of residual hematoma. RESULTS: Survival occurred in 10 of 12 SD animals, 10 of 12 CF animals, 10 of 12 QC animals, and 9 of 12 CX animals. No statistically significant difference was found. CONCLUSION: In our study of limited-access extremity bleeding, ChitoFlex® performed equally well in mitigating blood loss and promoting survival. The ChitoFlex® dressing is an equally effective alternative to currently available hemostatic agents. However, no agents were superior to standard gauze in our model of limited access.

Effect sizes for symptomatic and cognitive improvements in traumatic brain injury following hyperbaric oxygen therapy.

Hyperbaric oxygen therapy has been proposed as a method to treat traumatic brain injuries. The combination of pressure and increased oxygen concentration produces a higher content of dissolved oxygen in the bloodstream, which could generate a therapeutic benefit for brain injuries. This dissolved oxygen penetrates deeper into damaged brain tissue than otherwise possible and promotes healing. The result includes improved cognitive functioning and an alleviation of symptoms. However, randomized controlled trials have failed to produce consistent conclusions across multiple studies. There are numerous explanations that might account for the mixed evidence, although one possibility is that prior evidence focuses primarily on statistical significance. The current analyses explored existing evidence by calculating an effect size from each active treatment group and each control group among previous studies. An effect size measure offers several advantages when comparing across studies, as it can be used to directly contrast evidence from different scales, and it provides a proximal measure of clinical significance. When exploring the therapeutic benefit through effect sizes, there was a robust and consistent benefit to individuals who underwent hyperbaric oxygen therapy. Placebo effects from the control condition could account for approximately one-third of the observed benefits, but there appeared to be a clinically significant benefit to using hyperbaric oxygen therapy as a treatment intervention for traumatic brain injuries. This evidence highlights the need for design improvements when exploring interventions for traumatic brain injury and the importance of focusing on clinical significance in addition to statistical significance.

Unconventionally Acquired Brain Injury: Guidance and Instruction About an Emerging Challenge to Warfighter Brain Health.

Special Operations Forces have made brain health a medical priority in recent years, and new guidance identified a new challenge-unconventionally acquired brain injury (UBI). Although this emerging condition is described as a cluster of neurosensory and cognitive symptoms with unknown etiology/ origin, there remain critical questions about how this diagnosis differs from other brain injuries. More importantly, there are limited recommendations about how medical personnel should approach the problem. The current discussion will provide context and information about UBI based on higher guidance and will also review the scant literature to provide context. Foremost, UBI can be distinguished from traumatic brain injury (TBI) largely due to an unknown point of injury. The described symptoms otherwise appear to be largely the same as TBI. Likewise, the recommended course of treatment is to follow the Clinical Practice Guidelines for mild TBI/TBI even if the injury is an actual or suspected UBI. Personnel must be careful to avoid entering sensitive information into the medical record, which may be particularly challenging if identifying the cause involves classified information about an unconventional weapon. Finally, we briefly discuss the literature about several suspected incidents fitting UBI diagnostic criteria, and we conclude with five primary takeaways for medical personnel to follow.

Tactical Combat Casualty Care Scenario: Management of a Gunshot Wound to the Chest in a Combat Swimmer.

Tactical Combat Casualty Care (TCCC) has always emphasized the need to consider the tactical setting in developing a plan to care for wounded unit members while still on the battlefield. The TCCC Guidelines provide an evidence-based trauma care approach to specific injuries that may occur in combat. However, they do not address what modifications might need to be made to the basic TCCC guidelines due to the specific tactical setting in which the scenario occurs. The scenario presented below depicts a combat swimmer operation in which a unit member is shot while in the water. The unit casualty response plan for a combat swimmer who sustains a gunshot wound to the chest while on a mission is complicated by the inability to perform indicated medical interventions for the casualty while he is in the water. It is also complicated by the potential for ballistic damage to his underwater breathing apparatus and the need to remain submerged after wounding for at least for a period of time to avoid further hostile fire. Additionally, there is a potential for a cerebral arterial gas embolism (CAGE) and/or a tension pneumothorax to develop while surfacing because of the decreasing ambient pressure on ascent. The tactical response may be complicated by limited communications between the mission personnel while submerged and by the vulnerability of the mission personnel to antiswimmer measures if their presence is compromised.

Fluid Resuscitation in Tactical Combat Casualty Care; TCCC Guidelines Change 21-01. 4 November 2021.

Hemorrhagic shock in combat trauma remains the greatest life threat to casualties with potentially survivable injuries. Advances in external hemorrhage control and the increasing use of damage control resuscitation have demonstrated significant success in decreasing mortality in combat casualties. Presently, an expanding body of literature suggests that fluid resuscitation strategies for casualties in hemorrhagic shock that include the prehospital use of cold-stored or fresh whole blood when available, or blood components when whole blood is not available, are superior to crystalloid and colloid fluids. On the basis of this recent evidence, the Committee on Tactical Combat Casualty Care (TCCC) has conducted a review of fluid resuscitation for the combat casualty who is in hemorrhagic shock and made the following new recommendations: (1) cold stored low-titer group O whole blood (CS-LTOWB) has been designated as the preferred resuscitation fluid, with fresh LTOWB identified as the first alternate if CS-LTOWB is not available; (2) crystalloids and Hextend are no longer recommended as fluid resuscitation options in hemorrhagic shock; (3) target systolic blood pressure (SBP) resuscitation goals have been redefined for casualties with and without traumatic brain injury (TBI) coexisting with their hemorrhagic shock; and (4) empiric prehospital calcium administration is now recommended whenever blood product resuscitation is required.

Management of Hypothermia in Tactical Combat Casualty Care: TCCC Guideline Proposed Change 20-01 (June 2020).

As an outcome of combat injury and hemorrhagic shock, trauma-induced hypothermia (TIH) and the associated coagulopathy and acidosis result in significantly increased risk for death. In an effort to manage TIH, the Hypothermia Prevention and Management Kit™ (HPMK) was implemented in 2006 for battlefield casualties. Recent feedback from operational forces indicates that limitations exist in the HPMK to maintain thermal balance in cold environments, due to the lack of insulation. Consequently, based on lessons learned, some US Special Operations Forces are now upgrading the HPMK after short-term use (60 minutes) by adding insulation around the casualty during training in cold environments. Furthermore, new research indicates that the current HPMK, although better than no hypothermia protection, was ranked last in objective and subjective measures in volunteers when compared with commercial and user-assembled external warming enclosure systems. On the basis of these observations and research findings, the Committee on Tactical Combat Casualty Care decided to review the hypothermia prevention and management guidelines in 2018 and to update them on the basis of these facts and that no update has occurred in 14 years. Recommendations are made for minimal costs, low cube and weight solutions to create an insulated HPMK, or when the HPMK is not readily available, to create an improvised hypothermia (insulated) enclosure system.

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

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.