The demonstrated benefits of LVRS and the rigors of surgical lung volume reduction have led investigators and medical equipment manufacturers to develop minimally invasive techniques to achieve lung volume reduction without open thoracotomy. Devices and techniques under study include bronchial occlusion devices inserted via fiberoptic bronchoscopy, promotion of focal atelectasis and fibrosis by bronchoscopic injection of polymers into emphysematous regions of lung, bronchopulmonary fenestrations to enhance expiratory flow, and thoraco-scopic plication or compression of emphysematous lung. The goal of all of these procedures is to replicate the benefit of LVRS without the trauma, risks, and extended recovery of open LVRS.
A one-way endobronchial valve system has been developed (Emphasys Endobronchial Valve; Em-phasys Medical; Redwood City, CA) for the treatment of emphysema. The valve is designed for insertion into bronchi leading to emphysematous regions of lung. The intent is to promote atelectasis in emphysematous regions by preventing airflow into the bronchus while allowing outflow of air. The resulting atelectasis could reduce hyperinflation and dead space and allow expansion of previously compressed normal regions of lung, improving gas exchange. Emphysematous regions of lung may not always collapse following valve insertion due to collateral ventilation and/or severely reduced recoil in the lung distal to the valve. Even without atelectasis, the valve is intended to improve V/Q ratio by shifting ventilation away from emphysematous regions of dead space to better perfused areas of lung.
Furthermore, the one-way valve should inhibit dynamic hyperinflation of overly compliant emphysematous lung during exercise.