A collateral ventilation bypass trap system directly linked with a patient's lung or lungs may be utilized to increase the expiratory flow from the diseased lung or lungs, thereby treating one aspect of chronic obstructive pulmonary disease. The system includes a trap, a filter/one-way valve, an air carrying conduit and a retention device for securing system elements in position. The system also includes a flow restriction device for controlling the flow of air through the air carrying conduit.