LONDON (AP) - Swedish doctors have pioneered a technique that could dramatically increase the number of lungs available for transplant and save the lives of many who would otherwise die waiting for a donor.

The method, which involves injecting a coolant into the lungs after the heart has stopped beating, enabled lungs from a dead donor to be transplanted for the first time. It was described this week in The Lancet medical journal.

Organs start to deteriorate as soon as the heart stops beating. Until now, the main source of organ donations has been brain-dead people on life-support machines.

But scientists have recently discovered that the lungs have a unique ability to maintain themselves for about an hour after the heart stops beating because they fill with blood saturated with oxygen and the airways fill with air.

Dr. Stig Steen, professor of cardiothoracic surgery at the University of Lund in Sweden, describes in The Lancet how he successfully transplanted into a 54-year-old woman the lungs of a man who died of a heart attack in an intensive-care unit after a failed resuscitation attempt.

The man's lungs were injected through the chest with a coolant 65 minutes after he died. The cooling extends the ability of the lungs to survive for at least another 12 hours, Steen said.

The lungs were removed after three hours.

The recipient has so far survived for five months. Experts say that if lung transplants fail, it is usually in the first few hours.

``They have proven this is feasible,'' said Dr. Christopher McGregor, director of transplantation at the Mayo Clinic in Rochester, Minn., who was not involved with the research.

``This would be a completely new source of donors. It's a real advance,'' he said. ``The fact that the first case has gone well is very encouraging.''

Steen said potential new donors include people who die from bleeding brains or those killed in traffic accidents who are brought to the hospital in time for their lungs to be cooled.

Kidneys have been transplanted from dead people, but they have been removed from the bodies immediately, Steen said.

About half of all deaths in Sweden are caused by heart disease and problems with the blood vessels in the brain, the study said.

``This group could be a potential source of lung donors,'' it added. ``We hope that there will be enough donor lungs of good quality for all patients needing a lung transplant.''

The availability of donated organs varies widely from country to country. In some countries, such as Austria and Belgium, everyone is presumed to be a potential donor unless they specifically refuse. In most others, including in the United States, donors or their families must give permission before an organ is removed.

In the United States, there are about 3,000 people waiting for a lung transplant at any given time. About 850 of them will get one, according to statistics from the United Network for Organ Sharing, which manages the U.S. transplant waiting list. In 1999, 591 people died on the waiting list.

Transplant societies around the world say there are nowhere near enough donated organs to meet the need.

Current estimates indicate that of the 20,000 or so Americans who die each year under circumstances that make their organs suitable for transplant, only about 3,000 agree to donate them.

Copyright 2001 The Associated Press. All rights reserved.