a b s t r a c t

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 nonmed- ical 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 tourni- quet 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 perfor- mance 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 val- idation of a tourniquet practice program based on objective measurements.

(C) 2016

Introduction

Trauma is the leading cause of death between the ages of 1 and 44 years [1]. One of the most common causes of preventable trauma

? Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

?? Conflict of interest: The authors declare no conflicts of interest.

? Meetings: This study was presented at the 2015 Military Health System Research Sym-

posium conference.

* Corresponding author at: 13 Smilanski St, Rishon Le Zion 7525869, Israel. Tel.: +972 524257570.

E-mail addresses: erez_br@yahoo.com (E.N. Baruch), avi.benov@gmail.com (A. Benov), avishina@yahoo.com (A. Shina), amylaurenberg@hotmail.com (A.L. Berg), shlaifer.md@gmail.com (A. Shlaifer), elon.glassberg@gmail.com (E. Glassberg), james.k.aden2.civ@mail.mil (J.K. Aden), drtarifb@gmail.com (T. Bader), john.f.kragh.civ@mail.mil (J.F. Kragh), ayitzhak@gmail.com (A. Yitzhak).

death is limb injury [2-4] which may cause Massive bleeding that might lead rapidly to exsanguination and death [5-7]. Thus, time re- quired to control bleeding is of paramount importance even in civilian settings where hospitals are nearby the point of injury as at the Boston Marathon bombing [8-10]. Because military data from past conflicts have shown that prompt bystander use of tourniquets increases surviv- ability [6,11], civilian organizations, such as the American Heart Associ- ation and the American College of Surgeons, have recommended that lay bystanders should be competent in tourniquet use to stop bleeding from limb wounds [12,13].

Tourniquet use is now taught to nonmedical personnel in armies [14], law enforcements organizations [15], and civilian workplaces

[16] worldwide. Tourniquet practice programs can vary greatly, from in- struction cards [17] through video demonstrations [18] to a multiday course [19]. However, a performance comparison of different practice programs was not reported. Moreover, the lack of consensus is not

http://dx.doi.org/10.1016/j.ajem.2016.08.048

0735-6757/(C) 2016

limited to the type of the practice program. Even the amount of tourni- quet applications required in a practice session is unknown. No empiric comparisons of practice amounts were found in the medical literature, leaving the mainstay of any practice program undetermined. The aim of the present study is to compare performance in tourniquet use of nonmedical military recruits in a monthly tourniquet practice of either a single application or a triple application.

Methods

Materials

The Combat Application Tourniquet (CAT; Composite Resources, Rock Hill, SC) is the Israel Defense Forces’ (IDF) standard issue tourni- quet for controlling limb wound bleeding [20]. It is also the standard issue tourniquet in the US Armed Forces, according to the Committee of Tactical Combat Casualty Care [21,22]. The CAT is 38-mm-wide light- weight (~60 g) tourniquet. It uses a hook-and-loop fastener and a buck- le to fit a wide range of limb sizes, combined with a windlass system. The windlass uses a free-moving internal band to provide circumferen- tial pressure to the limb. Once tightened, it is then locked in place with a clip. All of the investigators in this study were competent with CAT use. The HapMed Leg Tourniquet Trainer (CHI Systems, Fort Washington, PA) is a simulated right-thigh body segment (serial no. 0023) with an amputation injury just proximal to the knee. The medial hip-pelvic area had an embedded computer interface which includes a touchpad. Software (version 1.12) internal to the mannequin allowed the leg to stand alone and be operated by user input through finger touch on the pad. Transducers in the mannequin can sense pressure and measure time, thereby reflecting the trainee’s success in Bleeding control [23]. The mannequin’s software allows the simulation of 7 built-in injury sce- narios. These scenarios differ from one another by the pressure thresh- old required to control bleeding (as required by different limb sizes). All uses were conducted with a scenario requiring a pressure threshold of 200 mm Hg. The mannequin was laid on a stretcher which was placed on the ground and was operated in accordance with the manufacturer’s instructions. There was no fluid or blood flowing out of the trainer; bleeding was simulated by red lights located in the wound area of the trainer. The number of lights illuminated represented the intensity of bleeding–all 26 lights on meant no control of bleeding, whereas no lights on meant bleeding had stopped. Intermediate control was indi-

cated by a few lights twinkling on and off.

Study design

Because this prospective educational study was a voluntary mannequin-based study, the Institutional Review Board of the IDF Med- ical Corps determined that it was not human subject research. The gen- eral design of the study was a preassessment and postassessment of the effect of an educational intervention in nonmedical personnel, as illus- trated in Fig. 1.

As part the standard combat training in the IDF, study participants underwent a 17-hour tactical field first aid course called the “Life Saver” course. The course curriculum includes practice in the following: Tourniquet application, basic wound dressing application, basic casualty evacuation, simple airway maneuvers, and education regarding envi- ronmental injuries. During the course, as performed routinely in the IDF [24], participants have practiced in applying a tourniquet on a fellow recruit’s limb (both arm and thigh) or on their own limb. Because a ces- sation of hemorrhage from a wound might be hard to identify while providing care at nighttime or under fire, participants were habituate to tight the tourniquet as much as they can in each application regard- less of a visual feedback of a hemorrhage. Effectiveness of application was determined by the absence of a distal pulse, as palpated by the Life Saver instructor. Pulse palpitation was conducted only after the par- ticipant had completed his application. There was no use of mannequins

in the course. All participants undertook written and practical examina- tions at the end of the course to possibly qualify as a “Life Saver.” In- structors in the Life Saver course are military medics who have undergone 4 additional weeks of “Life Saver Instructor” training in the School of Military Medicine, IDF Medical Corps [24].

Seven to fourteen days after completion of the Life Saver course (no tourniquet applications or training took place during this interval), an initial assessment was conducted. The initial assessment established the baseline tourniquet use performance of the participants before the educational intervention. Before the initial assessment, one of the inves- tigators briefed each of the participants individually. The briefing in- cluded an explanation of the study and the description of a scenario in which an amputated casualty (simulated by the mannequin) is lying be- hind cover, where no tactical threat is endangering the participant. Each participant was asked for a verbal consent to participate in the study. If he consented, the participant arrived at the assessment zone which was hidden to avoid cross-learning. To avoid any bias due to reasons which are not directly related to the participant ability to apply a CAT, the par- ticipant did not perform any rigorous physical activity before the assess- ment and did not carry any combat gear or weapon. The participant was placed approximately 0.5 m (1.5 ft) from the mannequin while holding a CAT in his hand. The participant was instructed to do his best at applying the tourniquet to the mannequin the instant the investigator ordered “Start!” (at which point the investigator activates the manne- quin). The investigator stopped the simulation only when the partici- pant stood up from the mannequin and called out “Done!”. No form of communication was allowed between the participant and the investiga- tor. All participants had one and only one initial assessment.

After initial assessment, the educational intervention was conduct- ed. Participants were allocated into 2 groups which differed only by the number of tourniquet applications per monthly practice session. The single-application practice (SAP) group was to conduct a single tourniquet application during a monthly practice session. The triple- application practice (TAP) group was to conduct a triple tourniquet ap- plication during a monthly practice session. Allocation to the study groups was based on the routine IDF randomized placement process. At adolescence, Israeli males undergo rigorous medical, cognitive, and psychosocial evaluation in IDF recruitment centers to determine their capabilities and placement in the army as service is compulsory [25,26]. These pre-enlistment scores are collected prospectively. Re- cruits who have arrived to an infantry brigade training camp were ran- domized into different platoons based on their pre-enlistment scores, ensuring psychotechnical and socioeconomic homogeneity within and between platoons to avoid any ability bias. Thus, all platoons were sim- ilar in size, demographics, and capabilities. This process is conducted routinely in any IDF infantry brigade. As part of the educational inter- vention, these platoons were allocated to the study groups using a flip of a coin–4 platoons to the SAP group and 5 platoons to the TAP group. Meaning, study allocation was based on randomized platoons and not on randomized individuals.

Each of the intervention’s practice sessions lasted several minutes per participant. All practice sessions were supervised by experienced military medics who were chosen by the brigade’s commanders and had undergone an additional 3-hour training by the investigators to en- sure competency in tourniquet use. This additional training was con- ducted with a ratio of 1 investigator to 3 medics. The training curriculum was divided into 2 parts: application technique and safety. The application technique part included the following: review of a proper tourniquet application technique, common pitfalls in tourniquet appli- cation [27], how to troubleshoot a failed application, and feedback tech- niques. The safety part included a review of the IDF Medical Corps CAT safety guidelines [20] and Possible complications of tourniquet applica- tion. Practice without supervision of these experienced medics was strictly prohibited. During sessions, the tourniquet was used by the par- ticipant on a fellow participant’s arm or thigh. Each participant was or- dered to do his best at applying the tourniquet while the supervisor

“Life Saver” course (n = 349)

Excluded

Not qualified as “Life Saver” (n = 42)

Excluded

No Initial assessment (n = 108)

Initial Assessment (n = 307)

Educational intervention – Allocation into different practice program groups

Excluded

SAP Final Assessment (n = 69)

No Final assessment (n = 13)

SAP group – 1 CAT application per monthly practice sessions (n = 82)

Excluded

TAP Final Assessment (n = 87)

No Final assessment (n = 30)

TAP group – 3 CAT applications per monthly practice sessions (n = 117)

Fig. 1. A flow chart illustrating assessments and interventions conducted in this study. As part of their standard combat training, study participants underwent the tactical field first aid Life Saver course. Seven to fourteen days after qualifying as “Life Savers,” participants’ performance in tourniquet use was assessed. Immediately after initial assessment, the study educational intervention was conducted, and participants were allocated into 2 groups which differed only by the number of tourniquet applications per monthly practice session. Allocation was based on platoons because participants were already randomized into similar platoons as part of the IDF routine process. Participants practiced according to their assigned program for 3 months and were then reassessed. Dropouts included 108 recruits who were not available for initial assessment and 43 recruits who were not available for final assessment. Because this study was conducted routinely during combat training of recruits, such training had to be stopped temporarily to allow participation. However, specific types of training could not be stopped, and thus, many recruits were then unavailable for study assessments.

observed his performance. If distal pulse was still palpable postapplication, the supervisor would feedback the participant and would correct his technique. No feedback was given during the applica- tion itself. Participants were not allowed to practice more than the allo- cated amount of practice, even in the case of failed application. All practice sessions were conducted according to the IDF Medical Corps CAT safety guidelines [20]. Safety was defined as an absence of adverse events (any undesirable sign, symptom, or medical or psychological condition) during and after the application of the tourniquet on a fellow participant’s limb. Uncomplicated pain that resolved promptly after device use was not considered an adverse event. The medics super- vising the practice sessions were instructed to report monthly to the in- vestigators on practice progress and immediately in the case of an adverse event.

Three months after initial assessment and initiation of the educa- tional intervention, study participants were reassessed. The final assess- ment method was identical to the baseline assessment described above.

Study population

The population of interest was the new male recruits of a single in- fantry brigade, enlisted to active military duty in November 2014, who had no previous medical training. A total of 349 recruits were available for the study. Inclusion criteria included successfully qualified as a “Life Saver,” participated fully in the group’s practice program, and attended both initial and final assessments. Excluded from the study were 42 re- cruits who did not qualify as “Life Savers.” Dropout included 108

recruits who were not available during initial assessment due to other training events and 43 recruits who were not available during final as- sessment. Thus, study included 87 participants in the TAP group and of 69 participants in the SAP group.

Analytical methods

Sample size required was estimated according to Fleiss test using Epi info Software (version 7.1.5.2; Centers for Disease Control and Preven- tion, Atlanta, GA), with a study power of 80% and an expected TAP to SAP participant ratio of 1:1. A sample size of 60 participants in each group was estimated to prove a hypothesis that TAP application time would be at least 15% shorter than the SAP application time. Because the study was conducted in an active combatant training ground, we ex- pected a dropout rate of 50%. Therefore, the sought initial size of the samples was at least 120 participants in each group.

Data were collected prospectively. Application time was measured in seconds and was defined as the time since the beginning of the assess- ment until the applied pressure reached the 200 mm Hg threshold and the mannequin sensed that the thigh was losing no more blood. In cases which participants could not apply sufficient pressure, application time was defined as the time from the beginning of the simulation until the participant called out “Done!” and stood up. Applied pressure was mea- sured in millimeters of mercury (mm Hg). In the event of a 0 mm Hg measurement when the participant called out “Done!” and stood up, he was defined as a participant who was unable to apply any pressure.

Descriptive statistics were used to report results. For intragroup comparisons of continuous data, a paired t test was used. A ?² test

Table 2

Comparison of mean differences in performance improvement between groups

was used for categorical data. Differences in performance from initial as-

sessment to final assessment were calculated for each parameter in

SAP group (n = 69)

TAP group P

(n = 87)

both groups. Group differences were compared to determine whether one group improved more than the other. The Student t test was per-

Improvement in application time (s) 8 +- 27.1 18 +- 28.5 .023

Improvement in applied pressure (mm Hg) 30 +- 124.2 39 +- 128 .649

formed to assess intergroup differences in means for continuous data. All t tests were 2 tailed. A Cochran-Mantel-Haenszel test was performed to compare between groups and across assessments the reduction in

Reduced proportion of participants who were unable to apply any pressure on the mannequin, n (%)

6 (8%) 16 (18%) .009

the proportion of participants who were unable to apply any pressure. P <= .05 was considered significant for all tests. Software included Microsoft Excel (version 2010, Microsoft Corporation, Redmond, WA) and JMP (version 10; SAS, Gary, IN).

Results

Median age was 18 years (interquartile range, 18-20), and all partic- ipants were males. These data were also similar among those who were excluded from the study. Table 1 summarizes the performances of both groups. Both groups had a similar results at initial assessment, as inter- group differences were not statistically significant (P = .6 for applied pressure, P = .07 for application time, and P = .3 for the number of par- ticipants who were unable to apply any pressure). After 3 months of practice, at final assessment, the SAP group had improved its mean ap- plication time by 8 seconds (P = .02) and mean applied pressure by 30 mm Hg (P = .05). The SAP group had no statistically significant dif- ference in its proportion of participants who were unable to apply any pressure. The TAP group had significantly improved its performance in application time by 18 seconds and in applied pressure by 39 mm Hg (P b .001 each), including a significant reduction in the proportion of participants who were unable to apply any pressure (45% during initial assessment vs 26% during final; P = .017).

Comparison of improvements between groups is detailed in Table 2.

The TAP group’s improvement in mean application time was signifi- cantly different and better than that of the SAP group (18 vs 8 seconds, respectively; P = .023). Although both groups had improved their ap- plied pressure in intragroup comparison from initial to final assessment, there was no significant difference in intergroup comparison (39 vs 30 mm Hg; P = .649). The TAP group improved more than the SAP group in reducing the proportion of participants who were unable to apply any pressure (18% reduction vs 8% reduction; P = .009).

No adverse event in either group was reported during the study.

Discussion

In this comparison of effectiveness of practice programs in nonmed- ical personnel, we found that 3 applications per practice session was su- perior to one in a monthly session over 3 months. This superiority was demonstrated by the differences of improvement between the groups. This difference in improvement represents the effect of a prospective practice program better than a point comparison between absolute values. For example, the absolute difference in application time be- tween the study groups is 4 seconds. However, this comparison disre- gards the small and statistically insignificant baseline differences

The difference in performance was defined as the final assessment’s result minus the ini-

tial assessment’s result. Mean differences and SDs are shown.

between the groups. Because of these small baseline differences, the dif- ference in improvement between the groups is 10 seconds–more than double the absolute difference and approximately 20% of an overall ap- plication time. Although tourniquet application is a lifesaving skill which is taught by commonly worldwide [15,21,28], no consensus for practice exists as no practice program has been prospectively validated yet. Other practice programs have shown their success with tourniquet applications by an observer ability to slide his index finger underneath a tourniquet [17] or by ultrasonic Doppler flow detectors which can dem- onstrate an absence of signal even when 20% of baseline blood flow is still present. In the present study, investigators demonstrated improve- ment in pressure and time as interobserver bias was avoided by the use of a mannequin. Moreover, the present study showed the feasibility of the TAP program, as practice took place in the field and was supervised by instructors who had only a medic’s education, like it will be per- formed in reality elsewhere. Thus, the TAP is a feasible and effective pro- gram which can be implemented by other organization wishing to train nonmedical personnel in tourniquet use. In addition, since currently there is no standard for tourniquet practice programs’ effectiveness, the TAP program’s results may be used in future comparisons of other programs.

An unintended cross-learning benefit was noticed in the TAP group.

Because practice included applications of tourniquet on a fellow’s par- ticipant limb, it allows cross-learning in that the recipient sees and feels the applier’s success and failure. Participants in the TAP group who apply more tourniquets per month unintendedly benefit more than SAP participants as practice continues. This finding supports prac- ticing tourniquet applications on a human (fellow recruit) model. Inter- mediate learners who need to personally feel the pressures and tensions required for reliable success will benefit from practicing on a fellow re- cruit. In addition, the cross-learning provides this experience in a shorter time; such a learning process would have taken much longer without cross-learning. Yet, we do not discourage the use of manne- quins because the use of both Mannequin models in tourniquet applica- tion practice can create a synergistic effect. Two mannequins are currently available for tourniquet practice in the IDF Medical Corps. The HapMed Leg Trainer used in this study (Fig. 2A) provides feedback to the user via its twinkling lights–all lights on meant no control of bleeding, whereas no lights on meant bleeding had stopped. The HapMed ability to directly measure time and pressure makes it an accu- rate tool for tourniquet performance assessment. However, it is costly (several thousand US dollars) and requires an electrical source to charge

Table 1 Performance results by practice groups
	SAP group (n = 69)				TAP group (n = 87)
	Initial assessment,	Final assessment,	Intragroup		Initial assessment,	Final assessment,	Intragroup
	mean (IQR)	mean (IQR)	comparison (P value)		mean (IQR)	mean (IQR)	comparison (P value)
Application time (s)	56 (41-67)	48 (34-60)	.02		63 (43.5-80)	44 (29.5-58)	b.001
Applied pressure (mm Hg)	123 (0-212)	153 (0-227)	.05		114 (0-224)	153 (0-228)	b.001
Participants not able to apply any pressure on	25 (36%)	19 (28%)	.361		39 (45%)	23 (26%)	.017

the mannequin, n (%) Abbreviation: IQR, interquartile range.

Fig. 2. The 2 tourniquet practice mannequins used by the IDF Medical Corps. A, The HapMed Leg Trainer used during the study. B, The Emergency Tourniquet Trainer used during combat training.

its battery after several hours of use. Therefore, the HapMed is used mainly for research purposes and not as a routine field tool. The Emer- gency Tourniquet Trainer (TraumaSim, Midvale, Australia) provides qualitative rather than quantitative performance assessment but pos- sesses a better feedback mechanism. The Emergency Tourniquet Trainer is composed of a tube covered by a thigh-shaped plastic. The tube is con- nected to a mechanical pump. Once the pump is activated, fluid is sprayed by the mannequin until a tourniquet applies enough pressure to collapse the tube (Fig. 2B). The Emergency Tourniquet Trainer allows both clear and instant feedback on the degree of bleeding control and an emotionally rewarding positive feedback for successful use. Moreover, this mannequin is relatively cheap (several hundred US dollars) and contains no electronics, making it suitable for field use. Because of its safety and quick feedback, mannequins should be used by novice users to understand indications, contraindications, procedure, mechanical goals, and determinants of success. Since 2015, the use of Emergency Tourniquet Trainer has become obligatory during the Life Saver course.

A high proportion of participants used the tourniquet so poorly that no pressure was applied on the mannequin by the end of their simula- tion. During initial assessment, 36% of the SAP participants and 45% of the TAP participants were unable to apply any pressure. After the educa- tional intervention, the TAP group performed better than the SAP group by reducing the proportion of participants who were unable to apply pressure (18% reduction vs 8%, respectively; P = .009). The US Armed Forces CAT success rate in caregiving on the battlefield is 79% [5]. The fact that approximately 1 of every 5 CAT applications failed was attrib- uted to narrowness of the CAT compared to wider tourniquets such as the Emergency & Military Tourniquet (EMT; Delfi Medical Innovations, Vancouver, BC, Canada), which is 2-fold wider than the CAT [29]. How- ever, the impact of user status, medical or nonmedical personal, was not assessed in that US military survey. Lakstein et al [30] reported higher percentage of tourniquet effectiveness when applied by medical per- sonnel compared to fellow nonmedical soldiers. Low CAT application success rate (20%-40%) of nonmedical personnel has been reported by Goolsby et al [17]. These data are worrisome, emphasizing the need for new and more methodical practice programs that will reduce the number of users who cannot apply enough pressure, as in the TAP group in our study. Postpractice screening, such as a periodic assess- ment of a randomized sample of the population of interest, could detect such poor performance. As a result of the current study, such screening is conducted in infantry brigades throughout the IDF since the summer of 2015, and its results are reported directly to the brigades’ com- manders. We believe that such screening programs should be consid- ered in other tourniquet teaching organizations.

The present study has several limitations. There was a high dropout rate of almost 50% overall. Because this study was conducted routinely during combat training of recruits, such training had to be stopped tem- porarily to allow participation. However, specific types of training could not be stopped, and thus, many recruits were then unavailable for study assessments. As this was expected in a study which was not conducted in an isolated environment dedicated solely to investigation, our initial sample size was purposefully more than double that needed. Because the final number of participants was higher than necessary (a sum of 156: 87 TAP and 69 SAP), we believe that dropouts did not significantly alter our findings. In addition, selected study duration was 3 months postintervention, as longer follow-up was not conducted. To assess the feasibility and performance of the practice programs on combat sol- diers, who actually serves as first aid providers, we conducted this study at the field, under real combat training conditions. Conducting an as- sessment required pausing of regular combat training and gathering of participants from remote training areas. Although assessing tourniquet use performance after 3, 6, 9, and 12 months of training would have been the preferred study design, because of operational constraints, we were able to conduct the assessment only at a 3 months postinter- vention period. Lastly, allocation to study groups was based on platoons rather than on individuals. During training in the IDF, recruits practice as a platoon and not as individuals. Conducting an allocation based on an individual randomization might require performance of the 2 practice programs concurrently in the same platoon, which would be intrusively and would significantly reduce the line commanders’ ability to comply with the study. Because platoons were created to be equal in size, in de- mographic and in capabilities as part of the routine IDF practice, we do not believe that a platoon-based allocation skewed results.

Conclusion

A monthly practice program of 3 applications per practice session was more effective than a program of a single application per session in improving the tourniquet use performance of nonmedical personnel. The TAP program is safe and feasible and can be supervised by medics. Although further study is needed to optimize tourniquet practice pro- grams, this study, which is the first reported comparison of programs that differ by amount of practice, shows that, in tourniquet use, practice does make perfect.

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