Ultrasonic tourniquets could stop blood vesselsfrom bleeding out by non-invasively coagulating blood using focusedsound waves.
Called the Deep Bleeder Acoustic Coagulation (DBAC)program, it aims to create a cuff-like device that wraps around awounded limb. Rather than applying pressure to the wound to stem theflow of blood, the device would use focused beams of ultrasound (soundwaves above the audible frequencies) to non-invasively clot vessels nomatter how deep they are. Accordingto the Pentagon's Defense Advanced Research Projects Agency (DARPA), these internal bleeding injuries are the leading cause of death forsoldiers in the battlefield.
Theultrasound tourniquet is intended to buy time, so that a medic can getthe patient to a better-equipped medical facility.
Surroundingtissue may be damaged in the process, since it will be heated close tothe boiling point. But the blood vessels remain functional because "theblood flow in the vessel cools the wall and so protects it.
Source: technologyreview.comAdded: 21 August 2006