IVOX may be the infant precursor of the artificial lung of the 21st century. The IntraVascular OXygenator is ready for human trials and awaiting approval by the Food and Drug Administration for those tests. The first phase is expected to begin soon at LDS Hospital in Salt Lake City, said Dr. JD Mortensen, who has devoted much of his 40-year career as a cardiopulmonary specialist to the quest for a device that would allow patients to survive a lung crisis. He now is chairman of the board and vice president of CardioPulmonics, a company that will market IVOX when it is ready.

"Nothing I've done has excited me so much," he said of the device, which has been in development for five to six years and is now patented. It will take therapy for impaired lung function a giant step beyond the mechanical oxygenators now routinely used to assist breathing.

IVOX consists of "an efficient, small oxygenator made of hundreds of thousands of hollow fibers." It is threaded through a leg or neck vein and pushed into the vena cava, the body's largest vein, which carries oxygen-depleted blood to the right atrium of the heart.

Once inserted, it unfurls, filling the vena cava with tiny fibers covered with a membrane that is only a micron thick. Oxygen is fed through the fibers and permeates through the membrane into the blood. At the same time, the gas-permeable fibers transmit carbon dioxide, breathing's waste product, from the blood into the hollow fibers so it can be removed from the body.

In animal experiments, IVOX has proved slightly more efficient at removing carbon dioxide than the natural lungs themselves, Mortensen said.

"It's pretty revolutionary to give oxygen and remove carbon dioxide intravenously," he said. "To date, we've not been able safely to relieve the lungs when they are ill and can't function."

"This may give us a way to keep people alive while their lungs recover the ability to do it. Now, when a patient is in dire circumstances, we have to use a ventilator; 40 percent of our targeted patients never get off the ventilator. The necessity of using high pressure to push oxygen into sick lungs can make things worse."

In addition, the IVOX patient will probably be awake and able to talk, as there is no tube in the throat and no need for medications related to the device.

The Salt Lake group plans to apply to the FDA within three months for approval of controlled clinical studies. A half dozen critically ill patients will be treated at LDS Hospital in Salt Lake City in the first phase of the trials, which will test the device for safety. In the second phase, patients will be treated at approximately four centers, Mortensen said. A number of American institutions have asked to be included in the research, as well as others in Japan and Europe.

IVOX is designed for short-term use in patients, but it raises an image for the future, Mortensen said. "If such a device were effective for seven days, why not seven weeks or seven years?"

The prospects hold hope in the 21st century for the 200,000 people each year in America's intensive care units who are on mechanical respirators, he believes, as well as for people with chronic lung ailments such as emphysema.