When Princess Diana's limo crashed in 1997, she might have lived if paramedics could have swiftly stopped the massive internal bleeding in her chest, lungs, and head. Now a group of scientists at the University of Washington in Seattle has developed an experimental technology that could rapidly seal off an accident victim's damaged blood vessels without the need for a single incision.
Doctors commonly stop hemorrhaging with powerful electrical currents that shrink blood vessels and induce blood clots, but the technique, called electrocautery, works only for wounds close to the surface. High-intensity ultrasound--waves having frequencies of one to 10 megahertz, far above the highest audible sounds--offers far more flexibility, claims bioengineer Shahram Vaezy. His team has found a way to focus very-high-energy ultrasound at precise sites deep within an injured area. The ultrasound beam is absorbed by the tissue and converted to intense, localized heat, which stops the bleeding by cauterizing the wound. "No other energy mode--not X rays, not lasers--can go deep and be brought into a tight focus," he says.
Current research focuses on surgical applications, but Vaezy envisions emergency medical technicians taking ultrasound equipment with them to the accident scene. "If there's internal bleeding because of blunt trauma--the person had high impact with the steering wheel, for example--we can use imaging technology to see where there's bleeding and apply high-intensity ultrasound to stop it," he says. Although he is still a year away from clinical studies, his tests convince him that noninvasive surgery could eventually save thousands of lives each year.
