Sealing up the lungs

Engineers at the University of Washington  have created a 'Star-Trek style' tricorder device that can seal punctured lungs using ultrasound.

The high-intensity ultrasound beams from the new unit focus on a particular spot inside the body on the patient's lungs. Focusing the ultrasound beams creates a tiny but extremely hot spot about the size and shape of a grain of rice. The rays heat the tissue and blood cells until they form a seal. Yet the tissue between the device and the spot being treated does not get hot, as it would with a laser beam.

'No one has ever looked at treating lungs with ultrasound before,' said Shahram Vaezy, a UW associate professor of bioengineering.

Indeed, physicists were sceptical that the idea would work at all, because a lung is essentially a collection of air sacs, and air blocks transmission of ultrasound. But now, experiments have shown that punctures on the lung's surface, where injuries usually occur, can be healed with ultrasound therapy.

'The results are really impressive,' Vaezy said. But he cautioned that the technique is still in the early stages of development and not yet being tested on human beings.

'You can penetrate deep into the body and deliver the energy to the bleeding very accurately,' Vaezy said. Recent tests on pigs' lungs showed that high-intensity ultrasound sealed the leaks in one or two minutes. More than 95 percent of the 70 incisions were stable after two minutes of treatment.

The findings suggest that ultrasound might replace what is now a painful, invasive procedure. Lung injuries are relatively common because the chest is a big surface that's often exposed to crushing or puncture wounds, said Gregory Jurkovich, chief of trauma at Harborview Medical Center in Seattle and a UW professor of surgery. A busy trauma room like Harborview's, he said, admits about two patients with bleeding lungs per day.

Often the bleeding can be stopped simply by packing the wound and applying pressure. In other cases, doctors insert a straw and drain the blood and air so the wound can heal. But in about one in 10 cases, neither of these methods is successful, and doctors must operate to stop the bleeding. That means making a long incision and separating the ribs, and then either sewing up the organ or removing a section of the lung.

The research was funded the National Institutes of Health, the Department of Defense and the National Space Biomedical Research Institute.