CAT WISE:

Throughout the history of war, from battles long ago to the recent conflicts in Iraq and Afghanistan, medics on the front lines have had one main goal: keep the injured alive until they can be safely evacuated to a treatment center.

While those killed in action since the beginning of the Iraq war are almost 90 percent fewer than during the Vietnam War, due in part to better medic training and faster evacuations, one of the biggest challenges medics still face is uncontrolled bleeding. It is the leading cause of preventable battlefield deaths.

And while tourniquets can be applied to certain extremity wounds, some areas of the body, like the armpit and pelvis, are difficult to compress. For those wounds, military medics have had to rely on a very simple tool.