devices and methods for altering gaseous flow within a lung to improve the expiration cycle of an individual , particularly individuals having chronic obstructive pulmonary disease . the methods and devices create channels in lung tissue and maintain the patency of these surgically created channels in tissue . maintaining the patency of the channels allows air to pass directly out of the lung tissue which facilitates the exchange of oxygen ultimately into the blood and / or decompresses hyper - inflated lungs .