Confidence-Competence Mismatch and Reasons for Failure of Non-Medical Tourniquet Users.

OBJECTIVE: Tourniquet application is a lifesaving skill taught worldwide in first aid bleeding control courses. We observed performance among non-medical users of tourniquets in their confidence, competence, and reasons for failure. METHODS: 179 Israeli military recruits without prior medical training underwent their standard first aid course where they learned Combat Application Tourniquet (CAT; Composite Resources, Rock Hill, SC, USA) use. After course completion, they self-reported confidence in tourniquet use. User performance was assessed 7-14 days later using a HapMed™ mannequin that assessed time, pressure, and blood loss. Competent performance required in aggregate: 1) use with pressure of 200 mmHg or more, 2) hemorrhage volume of less than 638 mL, and 3) correct placement of the tourniquet. For failed performance, a reason for failure was reported independently by both the user and an expert observer. RESULTS: 45 of 179 user performances (25%) were competent. Users who reported high confidence had only a slightly higher chance of achieving competence in tourniquet application (r = 0.17, p = 0.022). The most common reason for failure was excess slack in the CAT's strap (experts 55%, users 39%), and too few turns of the windlass (23% and 31%, respectively) was the second most common reason. Expert and user evaluations had poor agreement (κ = 0.44, 95% CI 0.32-0.56). CONCLUSION: The most common reason for failed use of tourniquets among non-medical users was excess slack in the tourniquet strap. Users self-evaluated their performance inaccurately and demonstrated a confidence-competence mismatch. These pitfalls in performance may help tourniquet instructors improve training of caregivers.

Bleeding Control With Limb Tourniquet Use in the Wilderness Setting: Review of Science.

The purpose of this review is to summarize tourniquet science for possible translation to wilderness settings. Much combat casualty data has been studied since 2005, and use of tourniquets in the military has changed from a last resort to first aid. The US Government has made use of tourniquets a health policy aimed to improve public access to bleeding control items. International authorities believe that education in first aid should be universal, as all can and should learn first aid. The safety record of tourniquet use is mixed, but users are reliably safe if trained well. Well-designed tourniquets can reliably attain bleeding control, may mitigate risk of shock progression, and may improve survival rates, but conclusive proof of a survival benefit remains unclear in civilian settings. Even a war setting has a bias toward survivorship by sampling mostly survivors in hospitals. Improvised tourniquets are less reliable than well-designed tourniquets but may be better than none. The tourniquet model used most often in 2016 by the US military is the Combat Application Tourniquet (C-A-T), and civilians use an array of various models, including C-A-T. Evidence on tourniquet use to date indicates that most uses are safe and effective in civilian settings. Future directions for study relevant to the wilderness setting include consideration of research priorities, study of the burdens of injury or capability gaps in caregiving for various wilderness settings, determination of the skill needs of outdoor enthusiasts and wilderness caregivers, and survey of wilderness medicine stewards regarding bleeding control.

Belts Evaluated as Limb Tourniquets: BELT Study Comparing Trouser Supporters Used as Medical Devices in a Manikin Model of Wound Bleeding.

OBJECTIVE: The purpose of the present study is to compare several models of commercially designed belts as used as a tourniquet. METHODS: In the Belts Evaluated as Limb Tourniquets (BELT) study, an experiment was designed to test the effectiveness of pants belts as nonimprovised medical devices to control hemorrhage in a manikin. Models of belts included Tourni-belt, Tourniquet Belt, ParaBelt, and Battle Buddy. Data collected included effectiveness, time to stop bleeding, total time of application, pressure, blood loss, and composite results (score count of good results; composite outcome good if every component was good). RESULTS: Differences in effectiveness percentages among models were not statistically significant. The difference in mean between users was statistically significant for stop time, total time, pressure, blood loss, composite score, and composite outcome. Mean time to stop bleeding differed for only 1 pair of models after the Tukey-Kramer adjustment; ParaBelt was faster than Tourniquet Belt. Mean total time of application differed between ParaBelt-Tourniquet Belt and Tourni-belt-Tourniquet Belt; the former model in both pairs was faster. No significant difference in mean blood loss measured by model was found. For composite outcome score, no pairwise difference between models was significant. For composite outcome (good-bad), ParaBelt had good results in 75% of tests; the other 3 models had significantly worse results. CONCLUSIONS: In a preliminary laboratory analysis of belt tourniquet models using a manikin, performance differed by model. ParaBelt performed better than other models for the composite outcome.

Does practice make perfect? Prospectively comparing effects of 2 amounts of practice on tourniquet use performance.

INTRODUCTION: Although a lifesaving skill, currently, there is no consensus for the required amount of practice in tourniquet use. We compared the effect of 2 amounts of practice on performance of tourniquet use by nonmedical personnel. METHODS: Israeli military recruits without previous medical training underwent their standard tactical first aid course, and their initial performance in use of the Combat Application Tourniquet (CAT; Composite Resources, Rock Hill, SC) was assessed. The educational intervention was to allocate the participants into a monthly tourniquet practice program: either a single-application practice (SAP) group or a triple-application practice (TAP) group. Each group practiced according to its program. After 3 months, the participants' tourniquet use performance was reassessed. Assessments were conducted using the HapMed Leg Tourniquet Trainer (CHI Systems, Fort Washington, PA), a mannequin which measures time and pressure. RESULTS: A total of 151 participants dropped out, leaving 87 in the TAP group and 69 in the SAP group. On initial assessment, the TAP group and the SAP group performed similarly. Both groups improved their performance from the initial to the final assessment. The TAP group improved more than the SAP group in mean application time (faster by 18 vs 8 seconds, respectively; P = .023) and in reducing the proportion of participants who were unable to apply any pressure to the mannequin (less by 18% vs 8%, respectively; P = .009). CONCLUSION: Three applications per monthly practice session were superior to one. This is the first prospective validation of a tourniquet practice program based on objective measurements.

Transfusion for shock in US military war casualties with and without tourniquet use.

STUDY OBJECTIVE: We assess whether emergency tourniquet use for transfused war casualties admitted to military hospitals is associated with survival. METHODS: A retrospective review of trauma registry data was made of US casualties in Afghanistan and Iraq. Patients with major limb trauma, transfusion, and tourniquet use were compared with similar patients who did not receive tourniquet use. A propensity-matching analysis was performed by stratifying for injury type and severity by tourniquet-use status. Additionally, direct comparison without propensity matching was made between tourniquet use and no-tourniquet use groups. RESULTS: There were 720 casualties in the tourniquet use and 693 in the no-tourniquet use groups. Of the 1,413 casualties, 66% (928) also had nonextremity injury. Casualties with tourniquet use had worse signs of hemorrhagic shock (admission base deficit, admission hemoglobin, admission pulse, and transfusion units required) than those without. Survival rates were similar between the 2 groups (1% difference; 95% confidence interval -2.5% to 4.2%), but casualties who received tourniquets had worse shock and received more blood products. In propensity-matched casualties, survival rates were not different (2% difference; 95% confidence interval -6.7% to 2.7%) between the 2 groups. CONCLUSION: Tourniquet use was associated with worse shock and more transfusion requirements among hospital-admitted casualties, yet those who received tourniquets had survival rates similar to those of comparable, transfused casualties who did not receive tourniquets.

U.S. Military use of tourniquets from 2001 to 2010.

OBJECTIVE: This study was conducted to associate tourniquet use and survival in casualty care over a decade of war in order to provide evidence to emergency medical personnel for the implementation and efficacy of tourniquet use in a large trauma system. METHODS: This survey is a retrospective review of data extracted from a trauma registry. The decade (2001-2010) outcome trend analysis of tourniquet use in the current wars was made in order to associate tourniquet use and survival in an observational cohort design. RESULTS: Of 4,297 casualties with extremity trauma in the total study, 30% (1,272/4,297) had tourniquet use and 70% (3,025/4,297) did not. For all 4,297 casualties, the proportion of casualties with severe or critical extremity Abbreviated Injury Scales (AIS) increased during the years surveyed (p < 0.0001); the mean annual Injury Severity Score (ISS) rose from 13 to 21. Tourniquet use increased during the decade by almost tenfold from 4 to nearly 40% (p < 0.0001). Survival for casualties with isolated extremity injury varied by injury severity; the survival rate for AIS 3 (serious) was 98%, the rate for AIS 4 (severe) was 76%, and the rate for AIS 5 (critical) was 0%. Survival rates increased for casualties with injuries amenable to tourniquets but decreased for extremity injuries too proximal for tourniquets. CONCLUSIONS: Average injury severity increased during the decade of war for casualties with extremity injury. Both tourniquet use rates and casualty survival rates rose when injuries were amenable to tourniquets.

Performance of Junctional Tourniquets in Normal Human Volunteers.

BACKGROUND: Inguinal bleeding is a common and preventable cause of death on the battlefield. Four FDA-cleared junctional tourniquets (Combat Ready Clamp [CRoC], Abdominal Aortic and Junctional Tourniquet [AAJT], Junctional Emergency Treatment Tool [JETT], and SAM Junctional Tourniquet [SJT]) were assessed in a laboratory on volunteers in order to describe differential performance of models. OBJECTIVE: To examine safety and effectiveness of junctional tourniquets in order to inform the discussions of device selection for possible fielding to military units. METHODS: The experiment measured safety and effectiveness parameters over timed, repeated applications. Lower extremity pulses were measured in 10 volunteers before and after junctional tourniquet application aimed at stopping the distal pulse assessed by Doppler auscultation. Safety was determined as the absence of adverse events during the time of application. RESULTS: The CRoC, SJT, and JETT were most effective; their effectiveness did not differ (p > 0.05). All tourniquets were applied safely and successfully in at least one instance each, but pain varied by model. Subjects assessed the CRoC as most tolerable. The CRoC and SJT were the fastest to apply. Users ranked CRoC and SJT equally as performing best. CONCLUSION: The CRoC and SJT were the best-performing junctional tourniquets using this model.

Which Improvised Tourniquet Windlasses Work Well and Which Ones Won't?

OBJECTIVE: Improvised tourniquets in first aid are recommended when no scientifically designed tourniquet is available. Windlasses for mechanical advantage can be a stick or pencil and can be used singly or multiply in tightening a tourniquet band, but currently there is an absence of empiric knowledge of how well such windlasses work. The purpose of the present study was to determine the performance of improvised tourniquets in their use by the type and number of windlasses to improve tourniquet practice. METHODS: A simulated Leg Tourniquet Trainer was used as a manikin thigh to test the effectiveness of improvised tourniquets of a band-and-windlass design. Two users made 20 tests each with 3 types of windlasses. Tests started with 1 representative of a given type (eg, 1 pencil), then continued with increasing numbers of each windlass type until the user reached 100% effectiveness as determined by cessation of simulated blood flow. Windlass types included chopsticks, pencils, and craft sticks. RESULTS: Effectiveness percentages in stopping bleeding were associated inversely with breakage percentages. Pulse stoppage percentages were associated inversely with breakage. The windlass turn numbers, time to stop bleeding, the number of windlasses, and the under-tourniquet pressure were associated inversely with breakage. The windlass type was associated with breakage; at 2 windlasses, only chopsticks were without breakage. Of those windlass types that broke, 20.7% were chopsticks, 26.1% were pencils, and 53.2% were craft sticks. CONCLUSIONS: A pair of chopsticks as an improvised tourniquet windlass worked better than pencils or craft sticks.

Next-generation tourniquet: Recommendations for future capabilities and design requirements.

BACKGROUND: Advances in tourniquet development must meet new military needs for future large-scale combat operations or civilian mass casualty scenarios. This includes the potential use of engineering and automation technologies to provide advanced tourniquet features. A comprehensive set of design capabilities and requirements for an intelligent or smart tourniquet needed to meet the challenges currently does not exist. The goal of this project was to identify key features and capabilities that should be considered for the development of next-generation tourniquets. METHODS: We used a modified Delphi consensus technique to survey a panel of 34 tourniquet subject matter experts to rate various statements and potential design characteristics relevant to tourniquets systems and their use scenarios. Three iterative rounds of surveys were held, followed by virtual working group meetings, to determine importance or agreement with any given statement. We used a tiered consensus system to determine final agreement over key features that were viewed as important or unimportant features or capabilities. This information was used to refine and clarify the necessary tourniquet design features and adjust questions for the following surveys. RESULTS: Key features and capabilities of various were agreed upon by the panelists when consensus was reached. Some tourniquet features that were agreed upon included but are not limited to: Capable of being used longer than 2 hours, applied and monitored by anyone, data displays, semiautomated capabilities with inherent overrides, automated monitoring with notifications and alerts, and provide recommended actions. CONCLUSION: We were able to identify key tourniquet features that will be important for future device development. These consensus results can guide future inventors, researchers, and manufacturers to develop a portfolio of next-generation tourniquets for enhancing the capabilities of a prehospital medical provider. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level V.

Early management of pediatric vascular injuries through humanitarian surgical care during U.S. military operations.

BACKGROUND: The objective of this report is to describe our experience of pediatric vascular injuries in a U.S. military combat support hospital in Baghdad, Iraq. A retrospective study was designed using Joint Theater Trauma Registry (JTTR) records in order to evaluate the pediatric (age <18 years) population presenting with vascular trauma to a combat hospital in Baghdad, Iraq between April 2006 and August 2008. Demographic data comprised casualty, age, gender, and mechanism of injury. Physiologic data included presenting vital signs (rectal temperature, blood pressure, and heart rate), arterial pH, base deficit, hemoglobin (g/dL), and international normalized ratio. RESULTS: Twenty-five children, median age 14 years (range, 5-17 years), median weight 48 kg (range, 15-80 kg) sustained 18 (72%) blast and 7 (28%) gunshot wounds. The mean Injury Severity Score was 25 ± 16.2. The median operative time for the vascular repairs was 189 minutes (range, 41-505 minutes). Patients were tachycardic (mean ± standard deviation, 136 ± 29 bpm), hypotensive (109/63 ± 29/19 mm Hg), and acidemic (pH 7.26 ± 0.07; BD -5.57 ± 5.1 mEq/L) on arrival to the emergency department and were physiologically improved upon admission to the intensive care unit 3 hours later. Repair techniques were ligation (14; 39%), saphenous graft (11; 31%), lateral suture (7; 19%), end anastomosis (2; 5%), patch (1; 3%), and thrombectomy (1; 3%). Twenty-four hour mean transfusion requirements included crystalloid 102 mL/kg (range, 19-253), transfused blood 47 mL/kg (range, 0-119), fresh frozen plasma 14 mL/kg (range, 0-68), and apheresis platelets (1.2 ± 3.68 units). Over a follow-up of 22 ± 5.5 days, the amputation-free survival was 80%. CONCLUSIONS: This is the largest reported wartime series to demonstrate in children that damage control resuscitation despite high injury severity permits simultaneous limb salvage.

Warning: Tourniquets Risk Frostbite in Cold Weather.

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.

Special topics.

Concerning the past decade of war, three special topics were examined at the Extremity War Injuries VII Symposium. These topics included the implementation of tourniquets and their effect on decreasing mortality and the possibility of transitioning the lessons gained to the civilian sector. In addition, the training of surgeons for war as well as residents in a wartime environment was reviewed.

Survey of trauma registry data on tourniquet use in pediatric war casualties.

OBJECTIVES: Previously, we reported on the use of emergency tourniquets to stop bleeding in war casualties, but virtually all the data were from adults. Because no pediatric-specific cohort of casualties receiving emergency tourniquets existed, we aimed to fill knowledge gaps on the care and outcomes of this group by surveying data from a trauma registry to refine device designs and clinical training. METHODS: A retrospective review of data from a trauma registry yielded an observational cohort of 88 pediatric casualties at US military hospitals in theater on whom tourniquets were used from May 17, 2003, to December 25, 2009. RESULTS: Of the 88 casualties in the study group, 72 were male and 16 were female patients. Ages averaged 11 years (median, 11 years; range, 4-17 years). There were 7 dead and 81 survivor outcomes for a trauma survival rate of 93%. Survivor and dead casualties were similar in all independent variables measured except hospital stay duration (median, 5 days and 1 day, respectively). Six casualties (7%) had neither extremity nor external injury in that they had no lesion indicating tourniquet use. CONCLUSIONS: The survival rate of the present study's casualties is similar to that of 3 recent large nonpediatric-specific studies. Although current emergency tourniquets were ostensibly designed for modern adult soldiers, tourniquet makers, perhaps unknowingly, produced tourniquets that fit children. The rate of unindicated tourniquets, 7%, implied that potential users need better diagnostic training. LEVELS OF EVIDENCE: Level 4; case series, therapeutic study.

Battle casualty survival with emergency tourniquet use to stop limb bleeding.

BACKGROUND: In a previous study conducted at a combat support hospital in Iraq, we reported the major lifesaving benefits of emergency tourniquets to stop bleeding in major limb trauma. Morbidity associated with tourniquet use was minor. STUDY OBJECTIVES: The objective of this study is to further analyze emergency tourniquet use in combat casualty care. DESIGN AND SETTING: This report is a continuation of our previous study of tourniquet use in casualties admitted to a combat support hospital (NCT00517166 at www.ClinicalTrials.gov). METHODS: After verifying comparable methodologies for the first study and the current study, we compared patient results for these two time periods and then pooled data to analyze outcomes with a larger sample size. RESULTS: The total study population was 499 (232 in the previous study and 267 in the current study). In all, 862 tourniquets were applied on 651 limbs. Survival was 87% for both study periods. Morbidity rates for palsies at the level of the tourniquet were 1.7% for study 1 and 1.5% for study 2; major limb shortening was 0.4% for both. Survival was associated with prehospital application (89% vs. 78% hospital, p < 0.01) and application before the onset of shock (96% vs. 4% after). CONCLUSIONS: This study shows consistent lifesaving benefits and low risk of emergency tourniquets to stop bleeding in major limb trauma.

Tourniquets exposed to the Afghanistan combat environment have decreased efficacy and increased breakage compared to unexposed tourniquets.

We hypothesize that an anecdotally observed increase in tourniquet breakage and decrease in efficacy may be secondary to environmental exposure during military deployment. This was a study comparing efficacy and breakage of 166 Afghanistan-exposed tourniquets to 166 unexposed tourniquets. Afghanistan exposure was defined as tourniquet carriage by field staff in the operational environment for approximately 6 months. In a controlled environment in the United States, a previously exposed tourniquet was tested on one thigh of each subject, while an unexposed tourniquet was tested on the opposite thigh. We recorded tourniquet efficacy (absence of distal pedal pulse for at least 30 seconds), breakage, and the number of turns required to stop the distal pedal pulse. A Wilcoxon sign-rank test was used to test differences between exposed and unexposed tourniquets. Tourniquets exposed to the environment broke more often (14/166 versus 0/166) and had decreased efficacy (63% versus 91%; p < 0.001). Three turns were required for most tourniquets to be efficacious. Environmental exposure of military tourniquets is associated with decreased efficacy and increased breakage. In most cases, tourniquets require three turns to stop the distal lower extremity pulse.

The military emergency tourniquet program's lessons learned with devices and designs.

OBJECTIVE: The purpose of this study is to report the device lessons learned from an emergency tourniquet program and, in particular, to emphasize analysis of discarded devices recovered after clinical use. METHODS: Discarded tourniquet devices were analyzed after use in emergency care of war casualties to determine wear and tear patterns, effectiveness rates, and associations among device designs. RESULTS: The 159 devices recovered comprised seven designs. Emergency & Military Tourniquet (92%) and Combat Application Tourniquet (79%) effectiveness rates were significantly different from each other and better than other tourniquets (p < 0.002) as the most effective ambulance and field tourniquets, respectively. Designs had specific pitfalls (e.g., sand-clogged ratchets) and strengths (the pneumatic design was least painful). Every device had wear, abrasions, or deformity about the band edges or bladder. User understanding of how devices work best helped attain better results. Some desirable traits (e.g., one-handed application, use for entrapped limbs) were rarely needed. Tourniquets fit casualty limbs well. CONCLUSIONS: Correct user actions (e.g., following the instructions to remove slack before twisting) led to device effectiveness, but misuse did not. Users often assumed that optimal use required more force, but this was associated with misuse. Training should include tourniquet pearls and pitfalls.

Minor morbidity with emergency tourniquet use to stop bleeding in severe limb trauma: research, history, and reconciling advocates and abolitionists.

BACKGROUND: In prior reports of active data collection, we demonstrated that early use of emergency tourniquets is associated with improved survival and only minor morbidity. To check these new and important results, we continued critical evaluation of tourniquet use for 6 more months in the current study to see if results were consistent. METHODS: We continued a prospective survey of casualties and their records at a combat support hospital in Baghdad who had tourniquets used at a combat hospital in Baghdad (NCT00517166 at ClinicalTrials.gov). RESULTS: After comparable methods were verified for both the first and current studies, we report the results of 499 patients who had 862 tourniquets applied on 651 limbs. The clinical results were consistent. No limbs were lost from tourniquet use. CONCLUSION: We found that morbidity was minor in light of major survival benefits consistent with prior reports.

Exploring Tourniquet Conversion in Simulation to Develop Concepts and Hypotheses.

BACKGROUND: Compared with those of tourniquet application, tourniquet conversion concepts are underdeveloped. The purpose of this project was to develop tourniquet conversion concepts and generate hypotheses. METHODS: One person performed 100 tests of tourniquet application and conversion. Testing varied by conversion types, materials, and assessments. Conversions were from improvised or Combat Application Tourniquets (C-A-T) to another C-A-T, a new site (with initial C-A-T only), a pneumatic Emergency and Military Tourniquet (EMT), or a pressure dressing (compression bandage or a roll gauze and an elastic wrap). Simulated limbs were created using plastic bottle-based manikins, pool noodle-based manikins, plastic pipes, glass bottles, a rain downspout, and a cardboard poster tube. RESULTS: Tourniquet application, conversion, and total times averaged 105, 132, and 237 seconds, respectively. Improvised tourniquet time was longer than that of C-A-T (p ≤ .05, all three). By initial tourniquet site, the 2-3 inches site had longer conversion and total time (p ≤ .02, both) compared with highest site. By whether initial tourniquets placed were also used in conversion, total time was shorter if yes (p = .05). Conversion to a pressure dressing was longer in conversion and total time (p ≤ .02, both) compared with conversion to a tourniquet. One wrap was short; we switched to those longer to cover limbs better. Limb types varied for indentation. Conversion communications improved when we used abbreviations and symbols. CONCLUSIONS: This preliminary project simulated tourniquet conversion to develop clinical concepts and research hypotheses to build a better basis for later research.