麻豆传媒

DOCTORS may eventually use sound waves to halt haemorrhages deep within the
body without having to slice into a patient.

There is no widespread method for stopping internal bleeding without surgery,
which is itself risky. As an alternative, some researchers are hoping to use
ultrasound to pinpoint, heat and cauterise internal wounds. But cooking tissue
in that way is too dangerous if bleeding occurs in areas such as the brain, or
if the problem is hard to pinpoint and doctors need to treat a large area of the
body.

Now a team from the University of Washington in Seattle has discovered that
high-intensity focused ultrasound beams can accelerate natural clotting, and
stop bleeding without heating up tissue.

Sound waves make blood move around more than usual. This activates platelets
by tricking them into thinking they are flowing through an open wound. In lab
experiments, the new method activated platelets, causing them to stick to
membranes and each other, both necessary steps for clots to form.

Such a technique could be a welcome or even life-saving option when
cauterising is too dangerous. 鈥淚t鈥檚 a phenomenon we are really excited about,鈥�
says team member Lawrence Crum. The researchers have also found that clotting
occurs more rapidly if gas-filled microbubbles called ultrasound contrast agents
are present. The bubbles are often injected into tissue as an aid for ultrasound
imaging.

The next step, according to team member Wayne Chandler, will be to learn how
to optimise the technique before moving on to animal then human tests, which
could take place in the next few years.