On the Battlefield

Closing the Gaps in Combat Casualty Care.

by Tom Marlowe, MMT Correspondent

The analysis will result in a revised strategic plan in combat casualty care for the command, which in turn generates requirements for an annual broad agency announcement (BAA) released by USAMRMC to fill gaps in its capabilities, Army Colonel Dallas Hack, the new director, told Military Medical Technology. USAMRMC makes the BAA available to industry via the Web.

“We will prioritize the combat casualty care research efforts based upon our analysis of the current situation and future threats,” Hack stated. “Updates to the broad agency announcement will reflect that. We have ongoing efforts to work with some of our academic and industry partners as funded through some of our congressional funding.” The analysis could continue for another six months or so before generating definitive thoughts, Hack estimated, but the colonel nevertheless provided some insight into where combat casualty care could use some advancements.

“The issues of combat trauma are changing somewhat because of some of the success that we have had to date,” Hack reflected. “We have made major progress in the area of hemorrhage from extremity injuries. The mission that we have is to find better ways of caring for wounded troops. First, saving their lives, and then reducing the effects of their injuries.” Hemorrhage historically has caused many combat casualty deaths, and non-compressible hemorrhage remains a significant problem. Medics cannot stop the bleeding in a non-compressible hemorrhage, which occurs when the bleeding is so bad in a wound that physical pressure or a tourniquet does not stop it.

A significant number of combat casualties die from non-compressible hemorrhages, Hack revealed. Care for other injuries has improved dramatically due to improved training for medics, advanced tools for medical care, rapid evacuation techniques, and other factors. About 80 percent of combat deaths result from wounds so severe that instantaneously putting the victim on an operating table with top surgeons wouldn’t save them, Hack added. The largest number of other deaths in the remaining 20 percent comes from non-compressible hemorrhages.

“What can do you about that? If you cannot put physical pressure on something to stop the bleeding, what can you do about it?” Hack asked. “That’s what we call homeostasis, which is causing the blood to clot when it gets out to areas where it shouldn’t be. But we have to be careful not to over-activate that so the blood doesn’t clot within the blood vessels and cause other problems. So homeostasis, which is the stoppage of hemorrhage, is our major effort in terms of live-saving efforts.”

Perhaps the biggest outstanding need in combat casualty care, however, is a test for traumatic brain injury, Hack commented.

“There is still no good test for the nonvisible traumatic brain injuries to determine if someone has one or not,” he noted. “Particularly, there is no blood test. When someone has a heart attack, a blood test can determine if someone had one or not. We don’t have that equivalent level of test for brain injury— whether it is a blood test, an imaging test or a neural-cognitive test.”

There are no drugs approved by the Food and Drug Administration to treat brain injuries, Hack continued, and many potential tests face challenges overcoming the skull and other factors.

“We have fallen back,” Hack lamented. “We have neglected it, in my opinion. This is a public health problem. We have this problem in the military but also in the civilian world with motor vehicle accidents, sports accidents and falls, and the like. It’s a significant public health problem, and we have not done a good job addressing it.”

TREATING HEMORRHAGING

Working at the U.S. Army Institute of Surgical Research (ISR), Army Colonel Brian Eastridge, director of the Joint Trauma System, agreed with Hack that non-compressible hemorrhages are a top concern. In fact, he reported, the Army and the Marine Corps is fielding new solutions to warfighters in Iraq to assist with compressible and non-compressible hemorrhaging.

“Early on in the conflict, we did an analysis of casualties killed in combat, and we found a certain percentage of casualties that were killed in the conflict that we would classify as potentially preventable deaths,” Eastridge said. “Those potentially preventable deaths were mostly from hemorrhaging. Much of the hemorrhaging that was truly preventable was extremity hemorrhage. Looking at the data that we compiled in our trauma registry, IRS went back and fielded a proposal for somebody to develop a better mousetrap.”

After an evaluation of 10 top tourniquet proposals, the result was a new tourniquet that warfighters could apply with one hand, that saved the Army money, and that was userfriendly. Now every deployed soldier carries a tourniquet, Eastridge said.

A study by Dr. John Kragh, an orthopedic surgeon, found a survival rate of 90 percent if a victim applied a tourniquet appropriately when an extremity vascular injury was bleeding. But if a casualty with the same injury pattern did not have a tourniquet or bled through their tourniquet, the mortality increased to 40 percent, Eastridge recalled.

For non-compressible hemorrhages, the Army and the Marine Corps teamed up to develop a new solution for homeostatic pressings to stop bleeding. Up until now, the Army has fielded a heat dressing and the Marine Corps a quick-clot application—both designed to stop bleeding in cases where tourniquets or pressure did no good.

“The quick clot was associated with a number of significant burn injuries because it produces an exothermic reaction when it is applied to vigorous bleeding,” Eastridge described. “The more you bleed, the hotter it gets, so there were some pretty significant burns associated with quick clot.”

Now ISR has tested a combat gauze that stops bleeding much more effectively than the heat dressing or the quick-clot application. Troops were scheduled to begin receiving the combat gauze by the end of the calendar year.

In addition, ISR continues to study the effects of Recombinant Factor VIIa and its impact on hemorrhage control. A study of Recombinant Factor VIIa in use by physicians in operations Iraqi Freedom and Enduring Freedom by Ronald Kembro, John Horton and Michel Wagner found 65 percent of military physicians had the drug available during their deployment. Seventy percent of survey respondents in the study, published in November, indicated they would use the drug again.

“Recombinant Factor Seven is a drug that has had some controversy because of its safety profile and not its efficacy profile,” Eastridge explained. “We studied that earlier in the conflict and found that the use of Factor Seven conferred a small survival advantage in patients that got Factor Seven, and there was no increased risk of complications from the drug.”

REVISITING RESUSCITATION

Eastridge elaborated on several treatment advancements in several other areas outside of hemorrhages.

“One of the biggest advantages we have seen come out of our research has been the way we resuscitate casualties,” he explained. “At the beginning of the war, we resuscitated casualties the same way we resuscitate casualties in civilian practice.”

Military medical personnel would follow a standard procedure of advanced trauma life support care to resuscitate casualties with fluids and then go to blood as required. But in recent years, medical experts recognized that a small percentage of casualties who truly require blood are going to need most of the blood resources. These casualties require massive resuscitation to stop vigorous bleeding, Eastridge observed.

“We developed a paradigm to look at these massive resuscitations and found that there are several factors that actually predict who is going to need one of these big blood resuscitations, including patients that come in shock; patients with multiple amputations; patients that have ongoing vigorous bleeding; and patients with hypertension or low blood pressure on admission,” he said.

Those who require massive resuscitation need blood as quickly as possible as their blood does not coagulate quickly. So the military has introduced a new resuscitation scheme in theater whereby it resuscitates those cases with higher ratios of fresh plasma in addition to blood to control coagulation. The result has been a decrease in mortality for the population of casualties that receive massive transfusions.

A recent study of the massive transfusion population showed that prior to the new resuscitation technique, the population suffered a mortality rate of 60 percent. Resuscitating casualties with a nearly 1:1 ratio of blood to plasma has decreased the mortality rate to 20 percent. Eastridge’s own survey of U.S. military casualties during the last 18 months or more has shown a mortality rate of 20 percent overall for severe casualties that make it to a medical treatment facility.

The concept of supplying more blood directly to massive resuscitation patients has caught on with the civilian medical community in the United States as well. Several medical groups, most notably a group at the University of Texas at Houston, have analyzed the results of the massive resuscitation technique and found a significant reduction in mortality for those who receive blood and platelets early and vigorously, Eastridge revealed.

CIVILIAN SYMBIOSIS

Military medical and civilian medical systems have close relationships and often learn from one another, forming a very useful “symbiotic relationship,” Eastridge said. Usually, civilian medical practitioners learn much more from military medical facilities as warfighters rapidly develop medical techniques to fulfill combat requirements. Once these techniques are proven, they often become part of civilian medical care procedures. Trauma systems in particular really started during the Vietnam War, Eastridge professed, providing civilian environments with the lessons from military rapid evacuation and surgical advancements.

“We didn’t have an effective emergency medical service system; we didn’t routinely supply helicopters for aeromedical evacuation,” Eastridge said. “So everybody at home saw all of the things we could do with trauma care on the battlefield. At the same time, the Institute of Medicine came out with a report about trauma as a significant disease entity in our country. It’s the number one cause of mortality in folks up to 40 years of age. It’s under-recognized as a disease entity in our country.”

Guidance from the American College of Surgeons and other organizations shaped an effective U.S. civilian trauma system in the wake of Vietnam, Eastridge continued, providing a means to reduce mortality by 15 percent overall by many estimates.

But in a turnabout from Vietnam, military medical personnel turned to the civilian sector to study advancements in trauma systems at the beginning of the wars in Afghanistan and Iraq as U.S. forces largely had lost their institutional memory of trauma systems. Capabilities to treat so many casualties so quickly had not been in practice since the Vietnam War, Eastridge asserted.

“So at the beginning of this war, several of us put together a concept that perhaps if we are going to have a protracted conflict, we ought to develop a trauma system. We actually began to develop this trauma system in 2004,” he declared.

The task was daunting as U.S. trauma systems may encompass hospitals in different states or regions, but military hospitals in the same trauma system could be nearly 8,000 miles apart on a different continent. The U.S. military trauma system also takes a robust look at all aspects of trauma care, Eastridge noted, looking at issues like prevention and mitigation. Data collected from medical examinations goes into developing improvements for body armor, for example.

“We also look at prehospital medical care and the new concept of tactical combat casualty care, which has really been pushed vigorously during this conflict,” he remarked. “That came out of the leadership of that group as well as the affiliation with the system. The system also has a lot to do with developing evidence-based best practice. Developing evidence-based best practice and clinical practice guidelines is really a contemporary hot topic in civilian trauma systems.”

SPEEDY SURGERY

The military also has been examining civilian practices with regard to damage control surgery and optimizing casualty transport time. In the case of damage control surgery, medics minimize immediate surgical time by performing limited surgery to control bleeding and thereby stabilize patients. Surgeons then undertake any definitive surgery at a later date. Civilian medical practitioners have espoused the concept of damage control surgery for the past 10 or 15 years, but it only has really caught on with the military medical community during the recent wars in the Middle East.

With regard to casualty transport time, military doctors are looking at improving prehospital transport time, driven by the concept of the “golden hour” of care immediately following severe injuries.

“The concept of the golden hour was proposed by R. Adams Cowley back in the 1970s, but it was really a marketing ploy,” Eastridge commented. “He was such an influential person at the right time in history that the concept has really stuck. There is not one shred of data to substantiate that time period.” Eastridge acknowledges the need for speed, however, as the faster a patient receives surgical treatment in severe trauma cases, the better their chances of survival.

“We are vigorously investigating the prehospital time element with respect to medical evacuation,” he said. “Basically, optimizing it not only has potential implications with respect to medical care, but it also has potential implications with respect to optimizing medevac resources.

“In both of the conflicts now—and I suspect with many conflicts in the future—the large majority of our medical evacuations from the battlefield are air medical evacuations. So we are vigorously looking at which casualties get the most benefit out of medevac and what is the optimal timing in which they should get to the hospital. We are just beginning that, but that has very high visibility from an operational standpoint,” he concluded. ♦