Attrition: Blood Simple

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September 27, 2012: The U.S. Army has developed an Intelligent Tourniquet (iTK) to save limbs, lives, and wear and tear on combat medics. The iTK uses a cell phone sized computer, an automated air bladder, and vital signs sensors to automatically loosen or tighten a tourniquet to minimize loss of blood in a limb but not to the extent that the limb will be lost (from lack of blood). Normally this task has to be monitored by a medic, who usually has multiple casualties to deal with. By using iTK the wounded soldier is getting precise monitoring of the tourniquet while the medic can attend to other casualties.

This is another example of how technology and over a decade of war have combined to create some major advances in emergency medicine. Major advances have been made to deal with heavy bleeding. In the past troops would often die from loss of blood before a surgeon could get in there to stop the bleeding. Even before iTK, several new technologies were developed, and used heavily, to sharply reduce the number of troops bleeding to death from combat wounds (which are often multiple and massive).

Over the last nine years the U.S. military has received several generations of clotting bandages (to stop heavy bleeding) and granular substances that have the same effect. This was a major medical advance to come out of the war effort. But, competition being what it is, there have been several clotting products, each operating a little differently.

Over 95 percent of the time these clotting devices stop bleeding, especially in areas where a tourniquet could not be applied. While medics, and troops, prefer the bandage type device there are situations where the fine granular substance is a better solution (especially in the hands of a medic).

In the first two years of use over 250,000 of these bandages were obtained for military needs. This was to make sure everyone in a combat zone had one at all times. While there are not a lot of casualties in base areas, the occasional rocket or mortar shell is likely to cause the kinds of wounds where these bandages can be a lifesaver. So it was a morale boost if everyone could carry one around (a small first aid kit is a standard part of combat equipment).

Following the introduction of the clotting devices, there were more cases of wounded troops getting to a hospital alive but in need of massive transfusions to replace lost blood. This led to the development of new, and much improved, techniques for getting a lot of blood into a patient who needed that done and done as quickly as possible without inducing shock or death from blood loss. The new procedures involved some use of the new clotting agents but were mainly about adjusting the amount of saline solution used along with the blood and tweaking the overall procedure. This was possible because there were so many of these cases encountered in Iraq and Afghanistan to try new techniques on. These were often situations where you had no choice but to try something new. The new techniques have reduced bleeding fatalities by over 75 percent and are one of the reasons why combat deaths are less than a third of what they were in Vietnam and previous wars.

Meanwhile, it will be a few more years before iTK has completed all its developments and testing and is ready for the troops.