Defense R&D supports ultrasound cuff to stem bleeding

The Defense Advanced Research Projects Agency (DARPA) has developed specifications for an ultrasound scanner tailored for the battlefield: one that searches for internal bleeding, targets the source, and then increases the beam intensity to coagulate the wound. The agency has tapped Philips Medical Systems to build it.

Rising to the challenge, the Dutch company has assembled a multidisciplinary team of engineers from its ultrasound division in Bothell, WA, experts in acoustic hemostasis at the neighboring University of Washington Applied Physics Laboratory, and researchers from Philips Applied Technologies in Houston, PA, and San Jose, CA.

Together they have begun a four-year project to create a device small enough to fit in soldiers' backpacks and smart enough to find the source of bleeding and stop it, when placed on an arm or leg wound.

"There are many challenges involved in getting from concept to work-in-practice," said Michael Pashley, research department head of ultrasound imaging and therapy for Philips Research North America. "The first is to create a somewhat intelligent system that takes the place of a trained physician, understands the ultrasound data, and automatically determines where the bleeding is. Then, on the side of actually coagulating the blood, there is the challenge of getting sufficient energy to the right place without damaging the surrounding tissue."

The need for such a device is evident, based on the kinds of wounds inflicted on American soldiers in Iraq by improved explosive devices. Body armor leaves arms and legs exposed, leading to debilitating and sometimes life-threatening injuries.

Specifications developed by DARPA call for a cuff-like device that would be applied to the arm or leg of a wounded soldier. An ultrasound transponder built into the cuff would search for and localize the source of bleeding much like an automatic defibrillator finds and analyzes the electrical signals of the fibrillating heart. The cuff would stem the bleeding with a high-intensity, focused ultrasound pulse, buying time to move a soldier to a field hospital where intensive care can be given.

DARPA officials hope the device will not only save soldiers' lives but also reduce the number of limbs lost. Such a device might also be adapted for civilian use.

"Being carried on an ambulance is one possible scenario," Pashley said.

DARPA funds awarded nearly a decade ago stimulated the development of the hand-carried ultrasound units now invigorating the ultrasound marketplace. Receiving some of these early grants were the UW Applied Physics Laboratory and ATL, a premier ultrasound vendor (DI SCAN 3/13/96, ATL begins work on futuristic miniature ultrasound scanner). Before its acquisition by Philips, ATL spun off the business unit charged with developing these scanners into a publicly held company. This company, SonoSite, pioneered handheld ultrasound.

This latest round of DARPA funding may foreshadow the next step in the evolution of ultrasound systems: miniaturized devices designed for specific applications.