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.

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.

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.

Effects of Donning and Wearing Personal Protective Equipment on Tourniquet Use and Conversion.

BACKGROUND: We sought to gather data about the effects of personal protective equipment (PPE) use on tourniquet interventions by preliminarily developing a way to simulate delay effects, particularly on time and blood loss. Such knowledge might aid readiness. Field calls to emergency departments may indicate donning of PPE before patient arrival. The purpose of this study was to investigate (1) delay effects of donning the PPE studied on field-tourniquet control of hemorrhage and (2) delay effects of wearing the PPE on application of a field tourniquet and its conversion to a pneumatic tourniquet. METHODS: The experiment simulated 30 tests of nonpneumatic field tourniquet use (http://www.combattourniquet.com/wp -content). The research intervention was the use of PPE. Data were grouped. The control group had no PPE (PPE0). PPE1 and PPE2 groups had mostly improvised and off-the-shelf equipment, respectively. PPE1 included donning a coat, goggles, face covering, cap, booties, and gloves. PPE2 had analogous items. The group order was randomized. A test included paired trials: field tourniquet, followed by conversion. An investigator simulated the caregiver. A task trainer simulated a thigh amputation. Donning delays were evaluated as differences in mean times to stop bleeding compared with PPE0. Blood loss results from donning PPE were calculated as the delay multiplied by its bleeding rate, 500mL/min. RESULTS: PPE0 had no delay: its mean blood loss was 392mL. PPE1 had 805mL more blood loss than PPE0 did. PPE2 exceeded PPE0 by 1004mL. Donning time (blood loss) for PPE1 and PPE2 were 1.4 minutes (712mL) and 1.7 minutes (863mL), respectively. The wearing of PPE did not slow down field tourniquet application or its conversion. CONCLUSIONS: How long it took to don PPE delayed the time to stop bleeding and increased blood loss, but wearing PPE slowed down neither field tourniquet application nor its conversion.

Conversion: Simulated Method of Exchanging Tourniquet Use for Pressure Dressing Use.

BACKGROUND: Given little data to assess guidelines, we sought a way to exchange one type of intervention, field tourniquet use, for another, use of a pressure dressing. The study purpose was to test performance of controlling simulated bleeding with a stepwise procedure of tourniquet conversion. METHODS: An experiment was designed to assess 15 tests of a caregiver making tourniquet-dressing conversions. Tests were divided into trials: tourniquet use and its conversion. In laboratory conditions, the tourniquet trial was care under gunfire; then, the conversion trial was emergency healthcare. A HapMed Leg Tourniquet Trainer simulated a limb amputation. An investigator provided healthcare. RESULTS: Mean (± standard deviation [SD]) test time and blood loss were 9 ± 3.6 minutes and 334 ± 353.9mL, respectively. The first test took 17 minutes. By test number, times decreased; the last six took ≤7 minutes. All tourniquet trials controlled bleeding. Mean (±SD) tourniquet pressure and blood loss were 222 ± 18.0mmHg and 146 ± 40.9mL, respectively. Bleeding remained uncontrolled in one conversion. Initial attempts to wrap a dressing were effective in 73% of tries (n = 11 of 15). Four of 15 wrap attempts (27%) were repeated to troubleshoot bleeding recurrence, and the first three tests required a repetition. Mean (±SD) dressing pressures and blood losses were 141 ± 17.6mmHg and 188 ± 327.4mL, respectively. Unsatisfactory conversion trials had a dressing pressure <137mmHg. Dressings and wraps hid the wound to impair assessment of bleeding. CONCLUSIONS: In testing a method of converting a limb tourniquet to a pressure dressing, the caregiver performed faster with experience accrual. The tourniquet results were uniformly good, but conversion results were worse and more varied. Simulating conversion was disappointing on a manikin and indicated that its redesign might be needed to suit this method. The procedural method constituted a start for further development.

Step Duration Effects on Blood Loss in Simulated Designs of Tourniquet Use Procedure.

BACKGROUND: We sought new knowledge by further developing a model of using calculations in the simulation of a first-aid task. The purpose of this study was to develop the model to investigate the performance of tourniquet use in its component steps. METHODS: We aimed to design an experiment on a desktop computer by mathematically manipulating simulated data in tourniquet use. A time factor of tourniquet use was ranged widely through time challenges in five degrees from ideal to worst performances. Redesigning the task was assessed by time costs and blood losses. RESULTS: The step of tourniquet application took 17% of the trial time and securing the tourniquet after bleeding control took the longest amount of the trial time, 31%. A minority of the time (48% [17% + 31%] to apply tourniquet plus secure it) was spent after the tourniquet touched the patient, whereas most of the time (52%) was spent before the tourniquet touched the patient. The step of tourniquet application lost 14% of the total blood lost, whereas no blood was lost during securing the tourniquet, because that was the moment of bleeding control despite securing the tourniquet taking much time (31%). Most (86%) of blood lost occurred before the tourniquet touched the patient. But blood losses differed 10-fold, with a maximum of 2,434mL, which, when added to a pretask indication blood loss of 177mL, summed to 2,611mL. Before redesigning the task, costs of donning gloves and calling 9-1-1 included uncontrolled bleeding, but gloving mitigated risk of spreading pathogens among people. By step and person, redesigns of the task altered the risk-benefit profile. CONCLUSIONS: The model was useful because it simulated where most of the bleeding occurred before the tourniquet touched the patient. Modeling simulated redesigns of the task, which showed changes in the task's risk-benefit profile by step and among persons. The model generated hypotheses for future research, including the capability to screen candidate ideas among task designs.

Deliberate Practice in Combat Application Tourniquet Placement by Loop Passage.

BACKGROUND: We sought opportunities to develop learning practices of individual first aid providers. In this study, we simulated deliberate practice in placing limb tourniquets. METHODS: This study comprised tourniquet uses by two experienced persons. Their practice sessions focused on developing a motor skill with periodic coaching. The Combat Application Tourniquet is 1.5-inches wide and was used in a technique of loop passage around the end of the limb to place it 2-3 inches above the wound. The simulated limb was a Z-Medica Hemorrhage Control Trainer. Both users applied the tourniquet six times over 5 days to accrue 30 uses individually (N = 60 tourniquet applications for the study). RESULTS: When represented as summary parameters, differences were small. For example, average ease of use was the same for both users, but such parameters only took a snapshot of performance, yielding a general assessment. However, for a learning curve by use number, a surrogate of experience accrual, application time revealed spiral learning. The amount that users compressed a limb averaged -15% compared with its unsqueezed state. Placement accuracy was classified relative to gap widths between the tourniquet and the wound, and of 60 performances, 55 were satisfactory and five were unsatisfactory (i.e., placement was <2 inches from the wound). When a tourniquet only overlaid the 2-inch edge of the placement zone (i.e., tourniquet was 2-3.5 inches away from the wound), no error was made, but errors were made in crossing that 2-inch edge. These gauging errors led us to create a template for learners to see and to demonstrate what the meaning of 2-3 inches is. CONCLUSION: Each metric had value in assessing first aid, but turning attention to gauging wound-tourniquet gaps revealed placement errors. Analysis of such errors uncovered what 2-3 inches meant in operation. Spiral learning may inform the development of best readiness practices such as coaching deliberate-practice sessions.

Ease of Use of Emergency Tourniquets on Simulated Limbs of Infants: Deliberate Practice.

BACKGROUND: To investigate questions about application of emergency tourniquets in very young children, we investigated practices of Combat Application Tourniquet (C-A-T) use on a simulated infant-sized limb to develop ways to improve readiness for caregiving. METHODS: This study was conducted as investigations of C-A-Ts used by two individuals in deliberate practice. The practice setup simulating a limb of infants aged 3-5 months included a handrail (circumference, 5.25 in.). This setup needed a specific modification to the instructions for use to adhere the band between the clips. Each user performed 100 practices. RESULTS: With accrual of experience, application time was shorter for each user, on average in a power law of practice, and more ease was associated when less time was taken to apply the tourniquet. The ease of use was associated with accrued experience through deliberate practice of a tourniquet user while under coached learning. A check of tourniquet fit on a 4.25-in. limb also entailed the modification used in the 5.25-in. limb. However, an additional modification of wrapping the band in a figure-8 pattern around the rod was needed because the rod and clip could not meet. The fit on a 3.25-in. limb was impracticable for a workaround. Tourniquet use was harder for smaller limbs (i.e., 4.25 in. and 3.25 in.). A map of tourniquet fit was sketched of which sized limbs were too big, too small, within the fit zone, or at its borders. CONCLUSION: C-A-Ts mechanically fit the simulated limbs of infants aged 3-5 months, and C-A-T use was practicably easy enough to allow experienced users to fit tourniquets to limbs well using a specific modification of the routine technique. The findings and knowledge generated in this study are available to inform researches and developments in best preparation practices for instructing first aid.

Limb Tourniquet Configuration: Preliminary Investigation of Problems and Principles.

BACKGROUND: A tourniquet's readiness during emergencies depends on how it is configured. We investigated configuration so ways of improving readiness can be developed. METHODS: This study was conducted at the Institute of Surgical Research in 2018 as sequential investigations by one user of Combat Application Tourniquets (C-A-Ts) in a band-and-rod design. RESULTS: Each tourniquet comes packaged with paper instructions for use, which include directions on how to configure it in preparation for caregiving. The paper and video instructions for use omit tensioning of the tourniquet in configuration, and the video misconfigured a time strap over the rod. In first-aid classrooms, we saw unwitting learners troubleshoot that misconfiguration. Problems with configuration were also seen in caregiving and with tourniquets stowed in kits. In deliberate practice, we self-applied a tourniquet to a thigh. In configuration after each of 100 uses, tourniquet elongation due to tensioning averaged 2.4 in was important for restoring the tourniquet to its full length. During configuration, if the C-A-T's stabilization plate slid along the band, out of position, the user slid the plate back into position. In various ways of testing other C-A-Ts, elongations averaged from 0.4 in to 0.9 in, depending on whether the tourniquet was self-applied or applied to a firm manikin. Elongation increments accrued as the tourniquet's band flattened. Configuration time averaged 22 seconds, and accrued experience improved the compactness of configuration. CONCLUSION: People are too often unreliable at putting C-A-Ts into the optimal configuration for use. That ready-to-use configuration includes the tourniquet being at its full length, having the stabilization plate positioned correctly along the band, and having the strap fastened to its clip of origin. When used, tourniquets had normal, small elongations in part due to band flattening. This tourniquet study showed the importance of optimal configuration to first-aid readiness practices.

Interoperable Readiness to Use Tourniquets by One's Familiarity With Different Models.

BACKGROUND: We investigated interoperability for a first aid provider to perform simulated use of three tourniquet models of maximal, moderate, and minimal familiarity. METHODS: The experiment was focused on the tourniquets used by an expert who rendered aid on a manikin by using three models of tourniquet with different extents of familiarity: The familiarity with Combat Application Tourniquet (C-A-T) was maximal; that for Special Operations Forces Tactical Tourniquet (SOFTT) was moderate, and that for Military Emergency Tourniquet (MET) was minimal. Each model had a band-and-rod design. Interoperability changes as intermodel differences were beneficial or costly in that performances were improved or impaired in units of time, ease, blood, and pressure. Each model had 10 tests, and test order was randomized by model. The HapMed Leg Tourniquet Trainer simulated a limb amputation. RESULTS: In comparison of interoperability burdens, sums of 10 test durations by model for C-A-T, SOFTT, and MET were 38, 77, and 64 minutes, respectively; C-A-T was fastest (p ≤ .002, both). The sums of times to stop bleeding for C-A-T, SOFTT, and MET were 334, 953, and 826 seconds, respectively; C-A-T was fastest (p ≤ .0013, both). The sums of blood losses for C-A-T, SOFTT, and MET were 2105, 3287, and 4256mL, respectively; that for C-A-T was least (p ≤ .0005, both). The mean ease of use differed, with C-A-T being easiest (p ≤ .0046, both). The mean pressure differed, with C-A-T being higher than SOFTT (p = .0073). CONCLUSIONS: Timesaving strongly favored the model with which the user had maximal familiarity. In theory and simulation, interoperability bears costs in successfully attaining it, in maintaining it, and in failing either. The user's familiarity with tourniquet model was associated with improved interoperability as seen by improved performances. If multiple models are fielded, then organizations may plan on extra spending, supplying, training, and managing.

Use Your Noodle to Simulate Tourniquet Use on a Limb With and Without Bone.

BACKGROUND: The purpose of this study was to simulate first aid by mechanical use of a limb tourniquet on a thigh with and without bone to better understand best caregiving practices. METHODS: Two investigators studied simulated first aid on a new pool "noodle," a plastic cylinder with a central air tunnel into which we inserted a wood dowel to simulate bone. Data were gathered by group (study and control, n = 12 each). The control group comprised data collected from simulated tourniquet use on the model with bone present. The study group comprised data from simulated tourniquet use on the model without bone. RESULTS: Comparing compression with and without bone, the mean volumes of compressed soft tissues alone were 303mL and 306mL, respectively. When bone was present, the volume of soft tissues was squeezed more, yielding a smaller size by 3mL (1%). The bone had a volume of 41mL and pressed statically outward with an equal force oppositely directed to the inward compression of the overlying soft tissues. With bone removed and compression applied, the mean residual void was 16mL, because 25mL (i.e., 41mL minus 16mL) of soft tissues had collapsed inward. The volume of the limb under the tourniquet with and without bone was 344mL and 322mL, respectively. The collapse volume, 25mL, was 3mL more than the difference of the mean volume of the limb under the tourniquet. More limb squeeze (22mL) looked like better compression, but it was actually worse-an illusion created by collapse of the hidden void. CONCLUSION: In simulated first aid, mechanical modeling demonstrated how tourniquet compression applied to a limb squeezed the soft tissues better when underlying bone was present. Bone loss altered the compression profile and may complicate control of bleeding in care. This knowledge, its depiction, and its demonstration may inform first-aid instructors.

Study of Tourniquet Use in Simulated First Aid: User Judgment.

BACKGROUND: The purpose of this study was to survey the judgments of tourniquet users in simulation to discern opportunities for further study. METHODS: The study design constituted two parts: questions posed to four tourniquet users and then their tourniquet use was surveyed in simulated first aid, where the users had to decide how to perform among five different cases. The questions addressed judged confidence, blood volumes, a reason bleeding resumes, regret of preventable death, hemorrhage assessment, need for side-by-side use of tourniquets, shock severity, predicting reliability, and difference in blood losses. The mechanical performance was tested on a manikin. Case 1 had no bleeding. Case 2 had limb-wound bleeding that indicated tourniquet use in first aid. Case 3 was like case 2, except the patient was a child. Case 4 was like case 2, except caregiving was under gunfire. Case 5 was like case 4, but two tourniquets were to be used side by side. Each user made tests of the five cases to constitute a block. Each user had three blocks. Case order was randomized within blocks. The study had 60 tests. RESULTS: In answering questions relevant to first-aid use of limb tourniquets, judgments were in line with previous studies of judgment science, and thus were plausibly applicable. Mechanical performance results on the manikin were as follows: 38 satisfactory, 10 unsatisfactory (a loose tourniquet and nine incorrect tourniquet placements), and 12 not applicable (case 1 needed no mechanical intervention). For cases 1 to 5, satisfactory results were: 100%, 83%, 100%, 75%, and 58%, respectively. For blocks 1 to 3, satisfactory results were 50%, 83%, and 83%, respectively. CONCLUSION: For tourniquet use in simulated first aid, the results are plausibly applicable because user judgments were coherent with those in previous studies of judgment science. However, the opportunities for further studies were noted.

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.

New and Established Models of Limb Tourniquet Compared in Simulated First Aid.

BACKGROUND: The performance of a new tourniquet model was compared with that of an established model in simulated first aid. METHODS: Four users applied the Combat Application Tourniquet (C-A-T), an established model that served as the control tourniquet, and the new SAM Extremity Tourniquet (SXT) model, which was the study tourniquet. RESULTS: The performance of the C-A-T was better than that of the SXT for seven measured parameters versus two, respectively; metrics were statistically tied 12 times. The degree of difference, when present, was often small. For pretime, a period of uncontrolled bleeding from the start to a time point when the tourniquet first contacts the manikin, the bleeding rate was uncontrolled at approximately 10.4mL/s, and for an overall average of 39 seconds of pretime, 406mL of blood loss was calculated. The mean time to determination of bleeding control (± standard deviation [SD]) was 66 seconds (SXT, 70 ± 30 seconds; C-A-T, 62 ± 18 seconds; p = .0075). The mean ease-of-use score was 4 (indicating easy) on a scale of 1 to 5, with 5 indicating very easy (mean ± SD: SXT, 4 ± 1; C-A-T, 5 ± 0; p < .0001). C-A-T also performed better for total trial time, manikin damage, blood loss rate, pressure, and composite score. SXT was better for pretime and unwrap time. All users intuitively self-selected the speed at which they applied the tourniquets and that speed was similar in all of the required steps. However, by time segments, one user went slowest in each segment while the other three generally went faster. CONCLUSIONS: In simulated first aid with tourniquets, better results generally were seen with the C-A-T than with the SXT in terms of performance metrics. However, the degree of difference, when present, was often small.

Laboratory Model of a Collapsible Tube to Develop Bleeding Control Interventions.

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.

Systematic review of prehospital tourniquet use in civilian limb trauma.

BACKGROUND: Military enthusiasm for limb tourniquet use in combat casualty care has resulted in acceptance by the trauma community for use in the prehospital care of civilian limb injuries. To date, there has been no report synthesizing the published data on civilian tourniquet use. The objective of this systematic review was to compile and analyze the content and quality of published data on the civilian use of tourniquets in limb trauma. METHODS: The MEDLINE database was searched for studies on civilian limb tourniquet use in adults published between 2001 and 2017. Search terms were tourniquet, trauma, and injury. Military reports and case series lacking systematic data collection were excluded. Counts and percentages were aggregated and weighted for analysis. RESULTS: Reports were included from six regional trauma centers and one interregional collaboration (total of 572 cases). One national prehospital database report was included but analyzed separately (2,048 cases). All were retrospective cohort studies without prospective data collection. Three reports defined a primary outcome, two had a nontourniquet control group, and no two articles reported the same variables. Limb injury severity and characteristics were inconsistently and incompletely described across reports, as were tourniquet indications and effectiveness. Arterial injury was reported in two studies and was infrequent among cases of tourniquet use. Mortality was low, and limb-specific complications were infrequent but variably reported. CONCLUSION: The rapid increase in the civilian use of tourniquets for limb hemorrhage control has occurred without a large amount or high quality of data. Adoption of a multicenter registry with standardized data collection specific to limb trauma and tourniquet use can serve to improve the trauma community's understanding of the safety and effectiveness of tourniquet use in civilian trauma settings. LEVEL OF EVIDENCE: Systematic review, level IV.

Assessment of User, Glove, and Device Effects on Performance of Tourniquet Use in Simulated First Aid.

BACKGROUND: The effects of users, glove types, and tourniquet devices on the performance of limb tourniquet use in simulated first aid were measured. MATERIALS AND METHODS: Four users conducted 180 tests of tourniquet performance in eight glove groups compared with bare hands as a control. RESULTS: Among tests, 99% (n = 179) had favorable results for each of the following: effectiveness (i.e., bleeding control), distal pulse stoppage, and tourniquet placement at the correct site. However, only 90% of tests ended with a satisfactory result, which is a composite outcome of aggregated metrics if all (patient status is stable, tourniquet placement is good, and pressure is good) are satisfactory. Of 18 unsatisfactory results, 17 (94%) were due to pressure problems. Most of the variance of the majority of continuous metrics (time to determination of bleeding control, trial time, overall time, pressure, and blood loss) could be attributed to the users (62%, 55%, 61%, 8%, and 68%, respectively). Glove effects impaired and slowed performance; three groups (cold gloves layered under mittens, mittens, and cold gloves) consistently had significant effects and five groups (examination gloves, flight gloves, leather gloves, glove liners, and glove liners layered under leather gloves) did not. For time to bleeding control and blood loss, performance using these same three glove groups had worse results compared with bare hands by 26, 18, and 17 seconds and by 188, 116, and 124mL, respectively. Device effects occurred only with continuous metrics and were often dominated by user effects. CONCLUSION: In simulated first aid with tourniquets used to control bleeding, users had major effects on most performance metrics. Glove effects were significant for three of eight glove types. Tourniquet device effects occurred only with continuous metrics and were often dominated by user effects.

Unwrapping a First Aid Tourniquet From Its Plastic Wrapper With and Without Gloves Worn: A Preliminary Study.

BACKGROUND: The purpose of this study was to gather data about unwrapping a packaged limb tourniquet from its plastic wrapper while wearing different types of gloves. Because already unwrapped tourniquets require no time to unwrap, unwrapping data may provide insights into the issue of having tourniquets unwrapped when stowed in a first aid kit of a Serviceperson at war. MATERIALS AND METHODS: In a laboratory setting, 36 tests of nine glove groups were performed in which four people, gloved and ungloved, unwrapped tourniquets. Other tourniquets were environmentally exposed for 3 months. RESULTS: All the users successfully unwrapped each tourniquet. Mean times to unwrap by glove group were not significantly different (p = .0961). When mean values of eight experimental groups were compared with that of one control group (i.e., bare hands), results showed no significant difference (p > .07). Mean time was least for bare hands (12 seconds) and most for cold gloves layered under mittens (22 seconds). Among the 36 pairwise comparisons of difference between glove group means, after adjustment for multiple comparisons, no comparison was noted to be statistically significant (p > .052, all 36 pairs). Glove thickness ranged from 0 mm for bare hands to 2.5 mm for cold gloves layered under mittens. By glove group, the thickness-time association was moderate, as tested by linear regression (R2 = 0.6096). The tourniquets exposed to the environment had evidence of rapid photodegradation due to direct exposure to sunlight. Such exposure also destroyed the wrappers. CONCLUSION: In a preliminary study, different gloves performed similarly when wearers unwrapped a tourniquet from its wrapper. The tourniquet wrappers gave no visible protection from sunlight, and environmental exposure destroyed the wrappers.