In a combat situation, a wounded soldier can bleed to death quickly without prompt attention. But depending on where the injury is, like a deep wound at the neck, shoulder, or groin, traditional treatments, such as tourniquets, may not be able to staunch the blood loss. So, engineering students at Johns Hopkins University, Baltimore, MD, invented an injectable foam system designed to quickly stop this type of profuse bleeding. The invention is designed to apply pressure and curb blood loss during the critical first hour during which a wounded soldier can be moved to a site for more advanced medical help.

They first identified two liquid chemicals that, when mixed, quickly form a polyurethane foam. The foam expands to fill the wound opening, then hardens, and applies pressure to the walls of the injury, which, they say, should lead to more effective targeting and treatment at the source of the bleeding.

The two chemicals—a polyol and a diisocyanate—that produce the foam remain in canisters that are stored separately within the injector device before they are needed. The students designed the canisters to keep the chemicals stable in military conditions at temperatures up to 100 degrees F for at least one year. The injector is about the size of a whiteboard marker. On the battlefield, the soldier administering the treatment would mix the two chemicals with a mechanism inside the injector. Then, pushing down the plunger would insert the expanding foam into the wound to reduce bleeding.