Artficial lung success

The device could help patients waiting for transplants

A device which could supplement or even replace failing lungs in humans has been tested successfully in animals.

The lung, which in theory could be implanted into the body, or sit outside it, is designed to help people waiting for transplants.

Similar bridge-to-transplant devices already work to assist weak hearts in preparation for such an operation.

Researchers from universities in Michigan and Texas developed the device, and claim it can reproduce 100% of normal lung function.

They have used it to keep a sheep alive for a week, and are hopeful that clinical trials in humans can start soon.

Hundreds of patients in the UK are potential candidates for lung transplantion - many of them suffer from the condition cystic fibrosis, or from diseases such as emphysema.

However, there is a desperate shortage of donor organs in the UK, and patients face a long wait, sometimes years, before a suitable donor can be found.

Many - like 13-year-old Lucy Travell-White this week - die before an operation can be attempted.

Until now, there is only one option for a patient with lung failure, and that is extracorporeal membrane oxygenation (ECMO), a device which replaces oxygen and removes carbon dioxide as the patient's blood is pumped through it.

However, long-term use of ECMO is not recommended.

Hollow fibre

The new artificial lung uses tiny hollow fibres to mimic the structure of a human lung, and increase the surface area available for oxygen to pass into the blood.

We've overcome the technical hurdles and now must confirm that it can truly take over from failing lungs for a longer time

Dr Robert Bartlett, University of Michigan

The resulting device is small enough to allow implantation into the body, where it would be attached to the pulmonary artery, the main blood vessel from the heart to the lungs.

From here, the heart's own pumping power would drive blood through it.

The lack of an artificial pump reduces potential damage to red blood cells as they pass through.

Dr Roger Bartlett, who is leading the research, said that he hoped it would allow patients to stay out of hospital and healthy while they waited for a transplant.

He said: "This generation of long-term, bridge-to-transplant implantable lungs is on the verge of reaching the patients who need it most, and have no other options.

"We've overcome the technical hurdles and now must confirm that it can truly take over from failing lungs for a longer time, and with less risk, than current life support technology."

Scarred lungs

Plans to start trials in humans will probably involve patients with pulmonary fibrosis, a progressive scarring of the lungs.

These patients have the highest death rate while on the waiting list for a transplant.

Dr Steve Tonge, from Aston University, is carrying out his own research into materials which can help oxygen exchange in the lungs, particularly those in premature babies, who often have breathing difficulties because their lungs are not fully developed.

He told BBC News Online: "You have to create a huge surface area - if you opened up a human lung, it would cover a tennis court.

"I can't imagine that you will ever be able to do it better than nature."

The results of early experiments with the device were presented at the ASAIO meeting into artificial organs in New York.