Ultrasound to treat war wounds

[Guest guest]

Ultrasound to treat war wounds

 

 

 

 

 

 

 

 

 

 

By Paul Rincon

 

 

 

Science reporter, BBC News

 

 

 

 

 

http://news.bbc.co.uk/2/hi/science/nature/5106598.stm

 

 

 

 

 

 

 

The technology could potentially save lives on the battlefield

 

 

 

The US military plans a portable device that uses focused sound

waves to treat troops bleeding internally from wounds sustained on the

battlefield.

 

 

Ultrasound can seal ruptured blood vessels deep within the body without the need for risky surgery.

 

 

The lightweight device has to be designed so that soldiers can operate it with minimal training.

 

 

Blood loss from wounds to the extremities is regarded as a major, preventable cause of battlefield death.

 

 

 

 

 

 

 

 

 

It's a grand challenge but we're keen to have a go at it

 

 

Lawrence Crum, University of Washington

 

 

 

 

The ability to treat soldiers with internal bleeding on the battlefield

could prevent combat deaths and amputations, according to a US military

presentation on the project.

 

 

These occur, it says, due to the delay involved in evacuating soldiers from the battlefield to a surgical facility.

 

 

The device would first use ultrasound imaging

technology, in particular " Doppler ultrasound " , to locate internal

bleeding. This employs a physical phenomenon known as the Doppler

effect to look for a characteristic signature of bleeding vessels.

 

 

It would then deliver a focused beam of high-powered ultrasound to those sites in order to cauterise the damaged vessels.

 

 

The Deep Bleeder Acoustic Coagulation (DBAC) programme is sponsored by the US Defense Advanced Research Projects Agency (Darpa).

 

 

Darpa envisages the device as a " cuff " containing an

array of ultrasound transducers, different elements of which will

detect bleeding and deliver focused, high-powered energy to the wound.

This cuff would be flexible enough to be wrapped around the treatment

area.

 

 

Competing teams - one headed by the multinational

Philips, the other by Seattle-based AcousTx Corporation - have both

been awarded contracts by Darpa to develop the technology.

 

 

'Serious effort'

 

 

The AcousTx team includes Siemens Corporate Research and

medical ultrasound company Therus. The Philips team includes

researchers at the University of Washington, Seattle, responsible for a

number of early studies showing that ultrasound could halt bleeding.

 

 

Together, the contracts are worth a potential $51m (£28m) over four years.

 

 

" This is a pretty serious effort. These groups are

working on making this an autonomous system that any soldier, or first

responder, could use in an emergency, " said Lawrence Crum, a member of

the team headed by Philips and an engineering research professor at the

University of Washington, Seattle.

 

 

Randy Serroels, general manager of AcousTx told the BBC

News website: " High-intensity focused ultrasound is already used in a

number of areas such as cancer treatment, fibroid treatment, and in

breaking up kidney stones, so the technology is available today. The

unique part is to combine that with imaging ultrasound and to automate

the procedure. "

 

 

Ultrasound stops bleeding partly by heating the damaged area and partly through mechanical effects.

 

 

The heating produced when this energy is absorbed

prompts an insoluble protein called fibrin to precipitate from blood,

forming a network of fibres that promotes clotting and plugs the wound.

Heating also denatures the blood vessel's connective tissue (collagen)

which helps form mechanical plugs and thermally " welds " tissue.

 

 

One mechanical effect is called streaming; the high

intensity beam pushes blood away from the injury, either back into the

vessel itself or to the sides.

 

In addition, the pressure changes induced by ultrasound

lead to the formation of bubbles in the blood - an effect known as

cavitation. This in turn may lead to the formation of free radicals -

highly reactive charged molecules - which accelerate the clotting

process.

 

 

Engineering challenge

 

 

While the science is reasonably well understood, it is the engineering that will determine success or failure.

 

 

Making the detection and treatment of bleeding an

automatic process perhaps poses the biggest challenge of the project,

according to Professor Crum.

 

 

" We've demonstrated in our laboratory that we can detect

internal bleeding and that you can stop it using ultrasound. But you

need a very intelligent, skilled administrator to do that, " he told the

BBC News website.

 

 

Describing the project as " high-risk, high-return " , he explained: " It's a grand challenge but we're keen to have a go at it.

 

 

" If one of these big companies could make one of these

it could be something like the [automated external] defibrillator. That

was also a remarkable challenge, now everyone has one. They are even

selling them for the home market. "

 

 

In about a year-and-a-half, the prototype technologies

will be put through their paces on a Stanford University testbed. This

is expected to involve " blind " tests on lab tissue.

 

 

Paul.Rincon-INTERNET