Minimizing Preventable Deaths
Written by Peter Buxbaum
MMT 2011 Volume: 15 Issue: 8 (December)
The prevention of hypothermia among battlefield casualties is a major challenge for combat medics, and not only in extreme cold conditions. Hypothermia is the fourth leading cause of preventable battlefield deaths. The most frequent cause is hemorrhage. And there is a connection between those two phenomena.
Hypothermia induces coagulopathy, a condition making blood clotting more difficult. “Even a small decrease in body temperature can interfere with blood clotting and increase the risk of exsanguination,” noted a 2010 memorandum from the Defense Health Board Tactical Combat Casualty Care (TC3) working group. “Combat casualties in shock are at even greater risk of hypothermic coagulopathy. Shock victims are thus predisposed to hypothermia.”
A TC3 protocol encourages combat medics encountering a casualty suffering from a penetration wound to be mindful of the implications for hypothermia. “Hypothermia is far easier to prevent than it is to treat,” said the TC3 memo, “so prevention of heat loss should begin as soon after wounding as the tactical situation permits.”
The U.S. military has acquired a number of products that help medics deal with this difficult battlefield situation. The armed services have also developed and acquired a range of cold weather garments, allowing warfighters to operate, and medics to treat casualties, in adverse conditions.
“Our primary goal is to help the patient create clotting factors at the point of injury,” said Captain Martin Stewart of the 10th Mountain Division Medical Simulation Training Center in Fort Drum, N.Y. “In hypothermic patients it becomes difficult for them to create their own clotting.”
“By using the right kind of gear and applying the right procedures it is possible to reduce the number of preventable combat deaths to zero,” said Ricardo Flores-Artola, director of military products at North American Rescue. “This has been documented among an Army Rangers unit that has been at the forefront of a lot of combat missions.”
Cold weather clothing helps warfighters and medics to work in cold weather conditions. “We fielded the third generation of our Extended Cold Weather Clothing System in 2006,” said Major Barry Castro, assistant product manager for cold weather clothing at the Army’s Program Executive Office Solider. “We heard from commanders in Afghanistan that our soldiers had the ability to fight in cold weather while the Taliban had to hole up and were unable to exercise tactical operations.”
“We understand the austere environments that warfighters face in theater,” said Sean McDearmon, Army branch specialist for W.L. Gore & Associates, the makers of Gore-Tex fabric, and a supplier to the Army’s Extended Cold Weather Clothing System (ECWCS). “Our innovation efforts are focused on the comfort and survivability of soldiers in these extreme weather situations.”
North American Rescue produces the Hypothermia Prevention & Management Kit (HPMK), which has been endorsed by TC3. “HPMK is specifically designed to prevent hypothermia during tactical casualty evacuation,” said Flores.
The HPMK includes the Heat Reflective Shell (HRS), constructed of a four-ply, composite fabric that provides thermal insulation and is impervious to wind and rain. The HRS has a built-in hood and fluid absorption pad. A system of hook and loop closures allows access by medics to the casualty. The kit also contains a self-heating, four-cell shell liner designed to sustain six hours of continuous dry heat at a temperature of 106 F.
The company’s ARC-TC Thermal Wrap is a single-use disposal product designed for early prevention and management of hypothermia as close as possible to the point of injury. “Within 90 seconds of activation, the unit delivers 104 F of continuous radiant heat to the casualty’s back and chest, lasting a minimum of five hours from a fully charged BA-5590 battery,” said Flores. “This heating solution overcomes the limitations of chemical, self-heating devices by providing the capability to quickly produce constant heat for a long duration, even in high altitudes and in moist environments. The chest heaters can be adjusted to evaluate the casualty’s chest by moving the chest flaps to the side during the examination.”
North American rescue is experimenting with a new Dupont material that could make its hypothermia wraps lighter, more rugged and more heat conductive. The company is awaiting approval from the Food and Drug Administration before introducing the product to the market.
Estill Medical Technologies Inc. produces Thermal Angel, which heats fluids such as blood, Hextend, and other intravenous fluids, providing a casualty with warm fluids in an effort to prevent hypothermia. “Thermal Angel regulates the infusate at 5,000 times per second, producing a normothermic output temperature of 38 C [100 F],” said Brandon Lopez, the company’s vice president for sales and marketing. “The Thermal Angel does not require calibration, cleaning or maintenance. It is very easy to use and set up. It was designed to follow the patient throughout the entire continuum of care, streamlining the training requirements and decreasing the logistical footprint associated with managing the trauma patient.”
Estill Medical also produces a portable power source for the Thermal Angel, known as the Thermal Angel Ultra Battery. A recently introduced product innovation reduces the weight of the power source from six pounds to 1.25 pounds. The Ultra Battery is chargeable from a variety of sources. “The caregiver can get out there on a mission,” said Lopez, “knowing that whatever power source is available will be able to charge the battery.”
The U.S. Army Center for Predeployment Medicine trains doctors and physician assistants in the use of Thermal Angel as part of a course provided to them 90 days before they are deployed to theater. “It is a one-hour block of instruction,” said Brian Hill, a physician assistant and instructor in the tactical combat medical care course, “and we continue to use the product throughout the week-long course. Thermal Angel introduces the fluids to the patient at slightly warmer than normal body temperature in order to help prevent hypothermia.”
“We have found that the hypothermic kit and the warm fluids are a really good combination,” said Stewart. “The new Thermal Angel battery system is more portable and more advantageous for medics to use on the battlefield.”
The U.S. Army’s Extended Cold Weather Clothing System is a collection of seven layers designed to be mixed and matched by individual warfighters to meet their mission needs and the conditions of the environments in which they are operating. The various components of the system are supplied by several different manufacturers and then kitted and supplied to the military by ADS of Virginia Beach, Va. The Soldier Protective and Individual Equipment office of PEO Soldier designed and initially fielded the system, but the Defense Logistics Agency is now in charge of awarding long-term contracts for the garments.
The first generation of ECWCS was introduced in the late 1980s and consisted of an outer layer parka and trousers, which incorporated the Gore-Tex fabric; a fleece middle layer; and long thermal underwear. The second generation replaced the middle and under layers with less bulky material that provided the same level of warmth.
“The third generation represents a significant improvement over the second generation,” said Castro. “We never before approached the problem holistically. This time we attacked the problem of layering by giving soldiers the option of removing and replacing layers.”
The seven ECWCS layers consist of silk-weight top and bottom undergarments made of a thin, moisture-wicking fabric followed by a light fleece layer. The fleece top is equipped with a half zipper so that the wearer can adjust the garment has he warms up.
The third layer is a fleece jacket that provides protection against cold but not wind. The next layer up is a wind shirt that provides wind protection. These two layers can be worn individually or together depending upon conditions.
The fifth layer is a soft shell top and bottom, including a jacket with hood, designed to provide cold weather protection but only limited protection from inclement weather. Next up is a is a seamsealed wet/cold weather jacket and trousers constructed with twolayer Gore-Tex fabric that is completely waterproof, windproof and breathable.
Technically it is not a “rain suit.” Its design and construction properties far exceed that of a simple rain suit. Finally, the seventh layer is a large puffy parka and trousers for use in extreme cold when performing stationary tasks such as guard duty.
“The system is tailorable to any mission,” said Castro. “As soldiers move and produce sweat they can take some layers off and put others on.”
The Army doesn’t produce policies as to when each layer should be worn. “We have a mandate to operate from 120 degrees to minus 60,” said Castro. “It is up to the soldiers and their leadership. The design of the system is user dependent. The feedback we have received from soldiers has been great.”
W.L. Gore does not manufacture garments itself, but supplies its Gore-Tex fabrics to others who product the components for ECWCS and other cold weather gear for the U.S. military. These pieces include outerwear, footwear and gloves. “We describe Gore-Tex fabrics as durably waterproof, windproof and breathable,” said McDearmon.
To produce a finished fabric, a Gore membrane is laminated to various textiles including nylon, polyester, or Nomex. Gore-Tex fabrics have been incorporated into every generation of Army ECWCS, as well as into outerwear for all other branches of the U.S. military.
TenCate Protective Fabrics likewise produces materials that are incorporated into garments manufactured by others. The company’s Defender M fabric was designed primarily to be flame resistant, but has been incorporated in gear designed to protect warfighters from the elements.
“The fabric was adopted by the United States Marine Corps for its inclement weather combat shirt,” said Mike Stanhope, the company’s global R&D manager. “The shirt is not designed for extreme conditions but for intermediate conditions requiring water repellent properties and protection from cold and wind. If you are wet and it is 55 degrees out, you may suffer from hypothermia which could lead to death.”
The shirt is worn as part of a layered system, usually against the skin and under the body armor, according to Stanhope. The Norwegian, Italian and Australian militaries have also adopted the TenCate Defender M protective materials for some of their forces’ gear. ♦