WikiJournal Preprints/Next Generation Junctional Tourniquet: A Case Report in a Non-injured Subject

Introduction
The leading cause of preventable death for today’s warfighter is junctional hemorrhage. A junctional hemorrhage is an externally compressible hemorrhage for which a standard extremity tourniquet with circumferential compression is ineffective. The anatomic junctions include the proximal groin, gluteal and pelvic regions, axilla and shoulder girdle, and the base of the neck. These are multidimensional dynamic joints with rotational forces and musculoskeletal anatomy preventing basic circumferential tourniquet compression. Circumferential compression is highly effective for peripheral-extremity injuries and has significantly reduced preventable battlefield fatalities due to hemorrhage. However, junctional hemorrhages have surpassed peripheral-extremity hemorrhages, as the leading cause of death from potentially survivable battlefield injuries. Eastridge et al reported junctional hemorrhages accounted for 19.2% of potentially survivable battlefield injuries whereas peripheral-extremity hemorrhages accounted for 13.5%. Several devices have been designed for combat medics to mitigate junctional hemorrhage. Field innovations and training in junctional tourniquet devices will save lives on the battlefield. The United States Army’s Report of the Dismounted Complex Blast Injury Task Force also noted the need for more research into junctional hemorrhage devices as “life-threatening ­bleeding in the groin or very proximal lower extremity regions” is often associated with dismounted complex blast injury. Multiple researchers and committees, including the Committee on Tactical Combat Casualty Care (CoTCCC), have reviewed and analyzed the current devices available for both a military combat and austere civilian trauma environment. The desirable traits of any junctional tourniquet have been well defined. In sum it needs to be small, light, easy to apply, and not slip (see Table 1).

Kowtal and Butler provided a comprehensive overview of the four current junctional tourniquets: The Abdominal Aortic and Junctional Tourniquet (AAJT),  the Combat Ready Clamp (CRoC), the Junctional Emergency Treatment Tool (JETT), and the SAM Junctional Tourniquet (SJT). The AAJT is not a true junctional tourniquet, but attempts to stop distal junctional hemorrhage via compression of the abdominal aorta. Thus, we have left it out of our comparison. A recent review of the currently available junctional tourniquets based on the above criteria found that the CRoC and SJT, compared to the JETT, have positive marks in the most categories. This coincides with our professional experience and opinion in that the SAM is the best device currently.

Table 2 presents a comparison of the current devices. Multiple disadvantages of these devices exist. They are expensive, bulky, time consuming to secure, do not consistently occlude the common femoral artery (CFA), and can shift with patient transport. A disadvantage specific to the CRoC is the inability to use a concomitant pelvic binder if needed for associated pelvic injury. And perhaps most significantly for reducing mortality on the battlefield, due to their size and weight, these tourniquets are often left out of the medic’s aid bag so not available at the point of injury. Drew et al specifically noted, in their review of both limb and junctional tourniquets, that the current models of junctional tourniquets may limit their use due to bulk and weight. Although we have not formally quantified percentages, our professional consensus is that less than ten percent of SOF and conventional medics carry a junctional tourniquet in their aid bag secondary to volume and mass. Combat medics need a junctional tourniquet that is small, lightweight, quick and easy to apply, and is reliable and stable for battlefield transport. Existing junctional tourniquets only stabilize in one direction and can easily slide from the optimal pressure point as demonstrated by Gaspary et el in a rigorous randomized comparison of the CRoC vs JETT vs SJT. This confirms what we have learned anecdotally from our combat experienced colleagues.

Patient Information
We present the case of a single patient (HAF) who did not have a traumatic injury at the time. Upon meeting the engineer (JTB), who, during professional conversation, presented a photo of an initial version of a junctional tourniquet that had been 3D printed for a medic. The physician then inquired if such devices had ever been shown to sufficiently occlude blood flow when applied at the common femoral artery (CFA). It had not, so the next day a pararescueman (JRV) and vascular surgeon (DEC) along with the engineer met at the 10th Field Hospital on Baghdad Diplomatic Support Center to apply it to the patient (HAF).

Materials and Methods
The original device, of which our team only had a photo, was modeled on an oral tobacco can with a slot for a single limb tourniquet to compress the CFA. Given only one limb tourniquet it only had two points of fixation. I.e. each end of the limb tourniquet was a single point of fixation. Thus, the system was still unstable and could easily slip during patient movement. We aimed to maximize the device stability using two limb tourniquets with a common slot for the lateral end of each (see figures 4 and 5). Consequently, it had three points of fixation on the patient. The device was printed via a Formlabs Form2 3D printer in resin. Sequential versions were iteratively printed and tested multiple times. The Air Force pararescueman (JRV) applied each device to compress the CFA on the first author with the other two authors present, during which arterial flow through the superficial femoral artery was evaluated using the Sonosite M-Turbo Ultrasound System. Each trial was done as part of the iterative design process in so much as to obtain enough feedback in order that the design could be improved and a new version 3D printed. The vascular surgeon determined successful compression of the CFA via her determination of cessation of flow in the SFA (Figure 1) on doppler. Each session led to device modification and improvement via the iterative design process following the principles of human centered design. The then final design is shown in figures 2 and 3. See figures 4 and 5 for detail on the use of two limb tourniquets to achieve three points of fixation. Besides the use of three limb tourniquets, the other major design innovation was the inverted mushroom top shape. Subsequent to returning home in the late summer 2018, we have made two additional modifications: the addition of nubs to the face to reduce lateral slippage and opening up the slots to eliminate the need to thread the limb tourniquet (Figure 6).

The currently available junctional tourniquets are bulky, ineffective, and expensive5-7. The multidisciplinary team provided a unique opportunity for collaboration with ideas, distinct skills, knowledge, and perspectives to create a clinically relevant solution. We developed a device for junctional hemorrhage control that has multiple advantages over the existing devices.

The NGJT is smaller and lighter than existing junctional tourniquets (Table 2). Further, the existing limb tourniquets are used with the NGJT, which reduces weight and space. This ensures each device can be easily carried in a medic’s personal aid bag on the battlefield. The NGJT is approximately 12% of the volume and 33% of the mass of existing junctional tourniquets. This makes it available at the point of need for immediate use because they will put it in their aid bags. The existing junctional tourniquets are too heavy and bulky for medics to carry and are often left in the vehicle or on base making them out of reach when needed.

The NGJT would likely be much less expensive than any current junctional tourniquets and may prove effective in both military and civilian medical communities. The NGJT can be 3D printed for approximately $10 U.S. dollars in resin. Mass production using injection molding would likely make them even more economical to produce. The need for a reliable junctional tourniquet translates to civilian trauma as well, given the modern-day risks for civilian mass casualty terrorist events. It has recently been proposed that civilian EMS be familiar with junctional tourniquets in the event of a mass casualty other than a terrorist attack or IED10. Although these authors mentioned the CRoC and the JETT, both may be prohibitively expensive and occupy too much space for many civilian EMS systems. A less expensive and more compact device would be more likely to be purchased by civilian EMS departments on strict budgets. The NGJT offers a far more affordable option.

Discussion
The application time for the NGJT is comparable to existing junctional tourniquets. Since the NGJT can use existing limb tourniquets, they can be wrapped around the patient with less movement of the patient via the medic sliding his/her hand under the patient with a single limb tourniquet strap in hand. The existing junctional tourniquets are not only larger, but require more patient movement as well as complex set up. Precise placement is essential to effectiveness, and thus adequate training is required prior to field use. The NGJT was designed, tested, and improvised based on anatomy and flow cessation on duplex ultrasound to optimize base shape and device stability. The device strap orientation was tested in a variety of configurations to ensure maximal stability and effectiveness. Overall, the NGJT is easier to use, easier to carry, and more effective than existing junctional tourniquets.

We see several areas for future improvement. Although our engineering innovations offers a lot of promise, we were not able to formally establish the best design. Might the same fundamental design, with a different shape, be applied to the challenge of junctional hemorrhage in the axilla? Most importantly the NGJT needs to be formally tested against both approved and in-development junctional tourniquets. We know of one emergency medicine physician exploring a repeat of the Gaspary protocol with the SAM versus NGJT.

Conclusions
We present a new device to address junctional hemorrhage, the leading cause of preventable death on the battlefield. It is smaller, lighter, and cheaper. The smaller and lighter nature of these devices ensure that any given medic will keep this potentially lifesaving piece of equipment close at hand. The device a medic carries will always be better than the device he or she doesn’t. Further, the decreased cost provides an opportunity for civilian EMS programs to take advantage of  life-saving devices. The increased accessibility and effectiveness of these field use junctional tourniquets offers the chance to save more lives on and off the battlefield.

Acknowledgements
We thanks United States Special Operations Command for providing the Mobile Technology and Repair Complex and enabling our innovation.

Competing interests
All authors with the exception of DT are on a patent obtained by the US Government for the NGJT. DT did the additional subsequent work of adding nubs and changing the slots.

US Military Disclaimer
All views presented are those of the authors and do not necessarily represent the views of DoD or its components.

Ethics statement
The sole subject was the first author.