Researchers at the University of Alabama at Birmingham injected a foam sealant into the lungs of a former smoker on Oct. 29, 2012, to treat his worsening emphysema. He was the first patient in the United States treated in a late-stage clinical trial of the AeriSeal System. The therapy, approved for use in parts of Europe and Israel, is undergoing investigation in the U.S. as a potential method of reducing lung volume in patients with severe emphysema.
Emphysema, a lung disease usually caused by smoking, damages air sacs in the lung called alveoli. The sacs fill with air that the body is unable to exhale, causing the lungs to expand. This in turn flattens the diaphragm, the primary muscle used for breathing. The flattened diaphragm is unable to function properly, making it extremely difficult for the individual to breathe. An estimated 4.9 million Americans have been diagnosed with emphysema.
A treatment known as lung volume reduction surgery has been employed to treat emphysema with some success. In the procedure, diseased portions of the lungs are surgically removed, allowing the lungs to return to a more normal size. This in turn allows the diaphragm to resume normal function. However, lung volume reduction surgery comes with substantial risk, including a 50 percent risk of major cardiac or pulmonary complications.
"We have been in search of a less-invasive way to achieve the same goal of lung reduction, without the risks inherent in surgery," says Mark Dransfield, M.D., associate professor in the division of Pulmonary, Allergy and Critical Care Medicine and primary investigator in the new study.
The AeriSeal System treatment is performed via a standard bronchoscopy, in which a bronchoscope is used to thread a catheter through the patient's airway to the most diseased areas of the lung. The foam, a proprietary polymer, comes in two liquid parts which are mixed together moments before injection. The addition of air to the mixture produces the foam. Within about 30 minutes of injection, the foam hardens to a rubbery consistency, blocking off the holes in the air sacs and causing sealing the damaged regions of lung. Over the course of several weeks, the air sacs deflate and the lung shrinks in size, clearing the way for the diaphragm to return to normal function.
"Based on previous studies and experience overseas, the AeriSeal System appears to be nearly as effective as lung volume reduction surgery without the more significant risks of surgery," says Dransfield. "The main side effect of this therapy is an immune system inflammatory response with flu-like symptoms that resolves over the course of two or three days."
University of Alabama at Birmingham