The Zephyr Endobronchial Valve (EBV) is a one-way valve that blocks off diseased lung sections to inhaled air but allows trapped air already inside the area to escape. This enables the collapse of the diseased part of the lung, allowing for the healthier parts of the lung to expand.

Emphysema, a type of chronic obstructive pulmonary disease, is an ongoing, progressive disease of the lower respiratory tract in the lungs. It is a seriously disabling disease with the potential for major complications and is often eventually fatal.

The symptoms of emphysema include shortness of breath and wheezing, an abnormal whistling sound made by the lungs during breathing. It is usually caused by smoking or other long-term exposure to inhaled irritants such as air pollution, chemicals, manufacturing fumes or small particles such as coal dust.

The randomized study, known as the LIBERATE study, is investigating the safety and effectiveness of the EBV for treating emphysema symptoms as compared to a current standard medical therapy program alone. Tanya Wiese, D.O., director of the Interventional Pulmonary Program, is principal investigator of the UofL study.

“The Zephyr EBV’s novel mechanism of action shows promise to help the healthy parts of the lung expand and reduce the effect of the disease,” Wiese said. “While not a cure, we believe this device could bring relief and improved quality of life to our patients with emphysema.”

The EBV can be placed by a doctor in a diseased section of the lungs using bronchoscopy, a procedure to access the lungs using a small tube with a camera on the end. With bronchoscopy, a physician can reach the airways in the lung by passing the tube through either the mouth or nose so invasive surgery is not required.

The problem of emphysema is particularly acute in Kentucky. The American Lung Association estimates that more than 56,000 Kentuckians, or 13 percent of the population, have emphysema, making the incidence of emphysema in Kentucky one of the highest in the United States.

Enrollment in the study is expected to be completed by the end of 2015 and patients will be followed for three years. To schedule an appointment to be screened for inclusion or for more information, contact Crissie DeSpirito at 502-852-0026 or Additional information on the LIBERATE study is available on the national clinical trials website,, using the Clinical Trials Identifier NCT01796392 or by calling 1-888-248-LUNG.

The other trial sites are Arizona Pulmonary Specialists, Cleveland Clinic, Duke University Medical Center, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Southern Illinois University School of Medicine, Temple University Hospital, University of Alabama at Birmingham, Beth Israel Deaconess Medical Center, University of Pittsburg Medical Center, The Mayo Clinic, University of California at Davis Medical Center,  University of California, San Francisco and University of Southern California.


The study is sponsored by Pulmonx Inc., a pulmonology-focused medical device company headquartered in Redwood City, California.

Jill Scoggins is Director of Communications at UofL's Louis D. Brandeis School of Law. She has been at UofL since 2010.