The number one priority to treating injuries on the battlefield is to stop the bleeding. But that's challenging when wounds penetrate deep in the body. Of the 5,800 Americans killed in battle since 2001, the vast majority died from hemorrhages that were potentially survivable.

So the army is now testing a new tool called XStat that uses a pocket-sized injector to send ninety-two tiny sponges into a wound, stopping bleeding in fifteen seconds. It serves up two essential elements: pressure and clotting.

XStat uses miniscule disk-shaped sponges made of sterile cellulose and coated with chitosan, a clotting agent. The sponges expand from just three millimeters thick to fifty millimeters when they're in contact with blood. This speeds up clotting, and equally important, it puts pressure on the blood vessels to slow bleeding.

Field medics now use field dressings or tourniquets with mixed results. They work well for surface wounds, but not for deep penetrating wounds where the medic needs to pack in gauze and hold it until the bleeding stops. But with XStat, the medic could inject the sponges into the wound and treat someone else. Since the sponges clump together, they can be easily removed later. Just to be sure, they're also labeled with an 'X' that can be easily spotted by X-ray. One XStat injection of sponges is equal to five rolls of combat gauze, yet takes up less space in a medic's pack.

The company developing it is also working on a smaller version to inject sponges into more narrow wounds caused by shrapnel, handguns or knives. This would save thousands of lives on the battlefield ' and we wouldn't be surprised if they eventually show up in an EMT's arsenal.