The McGowan Institute scientists are developing improved artificial lungs. Brack G. Hattler, MD, PhD, Professor of Surgery and Executive Director of the Medical Devices Laboratory at the University of Pittsburgh, and William J. Federspiel, PhD, the University’s William Kepler Whiteford Professor of Chemical Engineering, Surgery and Bioengineering, and Director of the Medical Devices Laboratory, currently are conducting laboratory research that is tackling fundamental problems associated with making artificial lungs more efficient and biocompatible, and is developing next generation artificial lungs or blood oxygenators.
The purpose of an artificial lung is to help lung-failure patients survive the tenuous bridge of time between loss of respiratory function and a lung transplant, and to allow a patient whose lungs have undergone trauma, like severe smoke inhalation, to rest and heal. Artificial lungs are small and portable, and are designed to allow patients to remain mobile and therefore stronger for surgery. In healthy lungs, blood vessels absorb oxygen from the blood that's pumped in from the heart, then release carbon dioxide through exhalation. An artificial lung basically imitates the way a normal lung works.
Researchers in Pittsburgh who are developing and testing prototypes believe artificial lung clinical trials in humans, similar to studies already underway in Canada and Europe, may begin as early as this spring.
"We are doing extensive work with the Department of Defense," says Dr. Hattler. "They are very interested in support of soldiers in combat." He expects human trials this spring for his group's external device, the Hemolung.
The Hemolung consists of a small cylindrical oxygenator that is approximately 4 inches in diameter. A cylindrical bundle of micro-porous hollow fiber membranes woven into a mat is wrapped in multiple layers around a central core. Oxygen flows through the hollow fiber membranes, while blood is circulated though the hollow fiber bundle. The core is spun at approximately 1000 RPM, dramatically enhancing gas exchange, as well as serving as a pump to move the blood through the external circuit. The 6-month clinical trial could begin early in 2008 on the Hemolung. Hope is that the FDA will approve it quickly, for patient use by the end of 2008.
Down the road, Dr. Federspiel hopes an implantable lung will be available to support patients with chronic diseases like asthma and cystic fibrosis. He and his laboratory have been exploring an enzyme that, when used to coat the fibers in the artificial lung, accelerates the removal of carbon dioxide from the blood and may reduce the amount of blood that needs to be fed through the device, making it more efficient and safer for patients.
According to the National Heart, Lung, and Blood Institute, 150,000 Americans experience lung failure each year. A third do not survive, and those who do often suffer permanent respiratory damage. One thousand wait in line for lung transplants; 25% will die because their lungs fail them while they wait.
Current treatment for lung failure is to hook patients up to an artificial respirator. It is costly, immobile, and requires intubation, a process that can cause infection, says John Conte, a heart-and-lung transplant surgeon and associate professor at Johns Hopkins University School of Medicine. "You don't want to take a patient who's been flat on his back, with poor muscles and infection at the IV site, and do a transplant. That's a recipe for disaster."
Illustration: McGowan Institute for Regenerative Medicine.
USA Today (01/29/08)
Medical Devices Laboratory
ALung Technologies, Inc.