An Assessment of Combat Medic Supraglottic Airway Device Design Needs Using a Qualitative Methods Approach: A Preliminary Analysis.

INTRODUCTION: Airway obstruction is the second leading cause of potentially preventable death on the battlefield during the recent conflicts. Previous studies have noted challenges with enrolling medics using quantitative methods, with specific challenges related to limited prior experience with the devices presented. This limited the ability to truly assess the efficacy of a particular device. We sought to implement a qualitative methods design for supraglottic airway (SGA) device testing. METHODS: We performed prospective, qualitative-designed studies in serial to discover emerging themes on interview. We obtained consent and demographic information from all participants. Medics were presented 2-3 airway devices in the same session with formal training by a physician with airway expertise to include practice application and troubleshooting. Semi-structured interviews were used after the training to obtain end-user feedback with a focus on emerging themes. RESULTS: Of the 77 medics surveyed and interviewed, the median age was 24, and 86% were male. During the interview sessions, we noted five emerging themes: (1) insertion, which pertains to the ease or complexity of using the devise; (2) material, which pertains to the tactile features of the device; (3) versatility, which pertains to the conditions in which the device can be used as well as with which other devices it can be used; (4) portability, which refers to how and where the device is stored and carried; and (5) training, which refers to the ease and frequency of initial and ongoing training to sustain medics' technical capability when using the device. CONCLUSIONS: In our preliminary analysis after enrolling 77 medics, we noted 5 emerging themes focused on insertion material, versatility, portability, and training methodology. Our results will inform the future enrollment sessions with a goal of narrowing the market options from themes to ideal device or devices or modifications needed for the operational environment.

Combat medic testing of a novel monitoring capability for early detection of hemorrhage.

BACKGROUND: Current out-of-hospital protocols to determine hemorrhagic shock in civilian trauma systems rely on standard vital signs with military guidelines relying on heart rate and strength of the radial pulse on palpation, all of which have proven to provide little forewarning for the need to implement early intervention prior to decompensation. We tested the hypothesis that addition of a real-time decision-assist machine-learning algorithm, the compensatory reserve measurement (CRM), used by combat medics could shorten the time required to identify the need for intervention in an unstable patient during a hemorrhage profile as compared with vital signs alone. METHODS: We randomized combat medics from the Army Medical Department Center and School Health Readiness Center of Excellence into three groups: group 1 viewed a display of no simulated hemorrhage and unchanging vital signs as a control (n = 24), group 2 viewed a display of simulated hemorrhage and changing vital signs alone (hemorrhage; n = 31), and group 3 viewed a display of changing vital signs with the addition of the CRM (hemorrhage + CRM; n = 22). Participants were asked to push a computer key when they believed the patient was becoming unstable and needed medical intervention. RESULTS: The average time of 11.0 minutes (95% confidence interval, 8.7-13.3 minutes) required by the hemorrhage + CRM group to identify an unstable patient (i.e., stop the video sequence) was less by more than 40% (p < 0.01) compared with 18.9 minutes (95% confidence interval, 17.2-20.5 minutes) in the hemorrhage group. CONCLUSION: The use of a machine-learning monitoring technology designed to measure the capacity to compensate for central blood volume loss resulted in reduced time required by combat medics to identify impending hemodynamic instability. LEVEL OF EVIDENCE: Diagnostic, level IV.

Your Metric Matters! Choose Wisely to Assess User Performance With Tourniquets in Simulated First Aid.

BACKGROUND: Readiness to perform lifesaving interventions during emergencies is based on a person's preparation to proficiently execute the skills required. Graphically plotting the performance of a tourniquet user in simulation has previously aided us in developing our understanding of how the user actually behaves. The purpose of this study was to explore performance assessment and learning curves to better understand how to develop best teaching practices. METHODS: These were retrospective analyses of a convenience sample of data from a prior manikin study of 200 tourniquet uses among 10 users. We sought to generate hypotheses about performance assessments relevant to developing best teaching practices. The focus was on different metrics of user performance. RESULTS: When one metric was chosen over another, failure counts summed cumulatively over 200 uses differed as much as 12-fold. That difference also indicated that the degree of challenge posed to user performance differed by the metric chosen. When we ranked user performance with one metric and then with another, most (90%; nine of 10) users changed rank: five rose and four fell. Substantial differences in performance outcomes resulted from the difference in metric chosen, which, in turn, changed how the outcome was portrayed and thus interpreted. Hypotheses generated included the following: The usefulness of a specific metric may vary by the user's level of skill from novice to expert; demonstration of the step order in skill performance may suffice for initial training of novices; a mechanical metric of effectiveness, like pulse stoppage, may aid in later training of novices; and training users how to practice on their own and self-assess performance may aid their self-development. CONCLUSION: The outcome of the performance assessments varied depending on the choice of metric in this study of simulated use of tourniquets.

Short Report Comparing Generation 6 Versus Prototype Generation 7 Combat Application Tourniquet® in a Manikin Hemorrhage Model.

BACKGROUND: The Combat Application Tourniquet® (C-A-T) is the standard-issue military tourniquet used in first aid in 2015, and the current model is called Generation 6. Soldiers in the field, however, have been asking for design changes in a possible Generation 7 to improve ease of use. This study compared the differential performance in use of the C-A-T in two designs: Generation 6 (C-A-T 6) versus a prototype Generation 7 (C-A-T 7). METHODS: A laboratory experiment was designed to test the performance of two tourniquet designs in hemorrhage control, ease of use, and user preference. Ten users of the two C-A-T models placed them on a manikin thigh to stop simulated bleeding. Users included trauma researchers and instructors of US Army student medics. Ten users conducted 20 tests (10 each of both designs). RESULTS: Most results were not statistically significant in their difference by C-A-T design. The mean difference in blood loss was statistically significant (ρ = .03) in that the C-A-T 7 performed better than the C-A-T 6, but only in the mixed statistical model analysis of variance, which accounted for user effects. The difference in ease-of-use score was statistically significant (ρ = .002); the C-A-T 7 was easier. All users preferred the C-A-T 7. CONCLUSION: In each measure, the C-A-T Generation 7 prototype performed similar or better than Generation 6, was easier to use, and was preferred.

Learning Curves of Emergency Tourniquet Use Exploring for Utility in Training.

BACKGROUND: Emergency tourniquet use to control hemorrhage from limb wounds is associated with improved survival and control of shock. In 2013, we introduced a way to measure learning curves of tourniquet users. With a dataset from an unrelated study, we had an opportunity to explore learning in detail. The study aim was to generate hypotheses about measurement methods in the learning of tourniquet users. METHODS: We gathered data from a previous experiment that yielded a convenient sample of repeated tourniquet applications used as a marker of learning. Data on consecutive applications on a manikin were used in the current report and were associated with two users, three models of tourniquet, and six metrics (i.e., effectiveness, pulse cessation, blood loss, time to effectiveness, windlass turn number, and pressure applied). There were 840 tests (140 tests per user, two users, three models). RESULTS: Unique characteristics of learning were associated with each user. Hypotheses generated included the following: trainee learning curves can vary in shape (e.g., flat, curved) by which metric of learning is chosen; some metrics may show much learning, whereas others show almost none; use of more than one metric may assess more comprehensively than using only one metric but may require more assessment time; number of uses required can vary by instructional goal (e.g., expertise, competence); awareness of the utility of specific metrics may vary by instructor; and some, but not all, increases in experience are associated with improved performance. CONCLUSIONS: This first-aid study generated hypotheses about caregiver learning for further study of tourniquet education and standards.

Junctional Tourniquet Training Experience.

Since 2009, out-of-hospital care of junctional hemorrhage bleeding from the trunk-appendage junctions has changed, in part, due to the newly available junctional tourniquets (JTs) that have been cleared by the US Food and Drug Administration. Given four new models of JT available in 2014, several military services have begun to acquire, train, or even use such JTs in care. The ability of users to be trained in JT use has been observed by multiple instructors. The experience of such instructors has been broad as a group, but their experience as individuals has been neither long nor deep. A gathering into one source of the collective experience of trainers of JT users could permit a collation of useful information to include lessons learned, tips in skill performance, identification of pitfalls of use to avoid, and strategies to optimize user learning. The purpose of the present review is to record the experiences of several medical personnel in their JT training of users to provide a guide for future trainers.

Testing of junctional tourniquets by military medics to control simulated groin hemorrhage.

BACKGROUND: Junctional hemorrhage is a common cause of death on the battlefield, but there is no documented direct comparison for the use of junctional tourniquet models by US medics. The purpose of this testing is to assess military medic experience with the use of junctional tourniquets in simulated out-of-hospital trauma care. METHODS: Nine medics (seven men and two women) used four different junctional tourniquets: Combat Ready Clamp™ (CRoC™; http://www.combatmedicalsystems .com), Abdominal Aortic and Junctional Tourniquet™ (AAJT™; http://www.compressionworks.net), Junctional Emergency Treatment Tool (JETT™; http://www.narescue .com), and SAM Junctional Tourniquet® (SJT®; http://www.sammedical.com/products). These medics also acted as simulated casualties. Effectiveness percentages, as measured by stopped distal pulse by Doppler auscultation, and time to effectiveness were recorded in two tests per tourniquet (72 total tests). Tourniquet users ranked their preference of model by answering the question: "If you had to go to war today and you could only choose one, which tourniquet would you choose to bring?" RESULTS: All tourniquets used were safe under the conditions of this study. Both the SJT and the CRoC had high effectiveness percentages; their rate difference was not statistically significant. The SJT and the CRoC had fast times to effectiveness; their time difference was not statistically significant. Users preferred the SJT and the CRoC; their ranked difference was not statistically significant. CONCLUSION: The SJT and the CRoC were equally effective and fast and were preferred by the participants.

Tragedy into drama: an american history of tourniquet use in the current war.

BACKGROUND: Although the scientific results of recent tourniquet advances in first aid are well recorded, the process by which tourniquet use advances were made is not. The purpose of the present report is to distill historical aspects of this tourniquet story during the current wars in Afghanistan and Iraq to aid scientists, leaders, and clinicians in the process of development of future improvements in first aid. METHODS: The process of how developments of this tourniquet story happened recently is detailed chronologically and thematically in a ?who did what, when, where, why, and how? way. RESULTS: Initially in these wars, tourniquets were used rarely or were used as a means of last resort. Such delay in tourniquet use was often lethal; subsequently, use was improved incrementally over time by many people at several organizations. Three sequential keys to success were (1) unlocking the impasse of enacting doctrinal ideas already approved, (2) reaching a critical density of both tourniquets and trained users on the battlefield, and (3) capturing their experience with tourniquets. Other keys included translating needs among stakeholders (such as casualties, combat medics, providers, trainers, and decision-makers) and problem-solving logistic snags and other issues. Eventually, refined care was shown to improve survival rates. From all medical interventions evidenced in the current wars, the tourniquet broke rank and moved to the forefront as the prehospital medical breakthrough of the war. CONCLUSION: The recorded process of how tourniquet developments in prehospital care occurred may be used as a reference for parallel efforts in first aid such as attempts to improve care for airway and breathing problems.

Survey of the indications for use of emergency tourniquets.

UNLABELLED: Indications and evidence are limited, multiple and complex for emergency tourniquet use. Good recent outcomes challenge historically poor outcomes. Optimal tourniquet use in trauma care appears to depend on adequate devices, modern doctrine, refined training, speedy evacuation, and performance improvement. Challenges remain in estimation of blood loss volumes, lesion lethality, and casualty propensity to survive hemorrhage. SUMMARY BACKGROUND DATA: Evidence gaps persist regarding emergency tourniquet use indications in prehospital and emergency department settings as indication data are rarely reported. METHODS: Data on emergency tourniquet use was analyzed from a large clinical study (NCT00517166 at ClinicalTrials.gov). The study included 728 casualties with 953 limbs with tourniquets. The median casualty age was 26 years (range, 4-70). We compared all other known datasets to this clinical study. RESULTS: Tourniquet use was prehospital in 671 limbs (70%), hospital only in 104 limbs (11%), and both prehospital and hospital in 169 limbs (18%).Major hemorrhage was observed at or before the hospital in 487 (51%) limbs and minor hemorrhage was observed at the hospital in 463 limbs (49%). Anatomic lesions indicating tourniquets included open fractures (27%), amputations (26%), soft tissue wounds (20%), and vascular wounds (17%). Situations, as opposed to anatomic lesions, indicating tourniquets included bleeding from multiple sites other than limbs (24%), hospital mass casualty situations (1%), one multiple injury casualty needed an airway procedure, and one casualty had an impaled object. CONCLUSIONS: The current indication for emergency tourniquet use is any compressible limb wound that the applier assesses as having possibly lethal hemorrhage. This indication has demonstrated good outcomes only when devices, training, doctrine, evacuation, and research have been optimal. Analysis of emergency tourniquet indications is complex and inadequately evidenced, and further study is prudent. Prehospital data reporting may fill knowledge gaps.

The impedance threshold device (ITD-7)--a new device for combat casualty care to augment circulation and blood pressure in hypotensive spontaneously breathing warfighters.

Inspiration through -7cm H2O resistance results in an increase in venous blood flow back to the heart and a subsequent increase in cardiac output and blood pressure in hypotensive animals and patients. Breathing through the impedance threshold device with 7cm H2O resistance (ITD-7) also reduces intracranial pressure with each inspiration, thereby providing greater blood flow to the brain. A new device called an ITD-7 was developed to exploit these physiological mechanisms to buy time in hypotensive War Fighters when other therapies are not readily available. Animal and clinical data with the ITD-7 demonstrate the potential value and limitations of this new non-invasive approach to enhancing circulation.