Patent ID: 8082921

Claim:
A method for reducing the residual volume of a target lung area which is connected to neighboring lung areas with collateral airflow channels, the method further maintaining patency of and without obstructing the bronchii leading to the target lung area, said patency maintained in order to prevent post obstructive pneumonia the method comprising: a. placing the distal tip of an indwelling catheter in a feeding bronchus proximal to and ventilating said target lung area, wherein said catheter is anchored in said proximal feeding bronchus without occluding said bronchus, and wherein the catheter remains in place for an extended treatment period lasting longer than 30 minutes; b. causing a decrease in residual volume in the target lung area, the decrease causing a remodeling of neighboring lung areas, the decrease caused by displacing during the treatment period the native respiratory gases consisting of oxygen, CO2 and N2 naturally residing in the target lung area, displacing said gases by delivering through said catheter a diffusible low molecular weight (DLMW) gas which is at least twice as diffusible as the respiratory gases, wherein the diffusibility of the DLMW gas allows more volume of DLMW gas to diffuse through the collateral channels into neighboring lung areas compared to the volume of respiratory gas diffusing through the collateral channels into the target lung area from neighboring areas; c. maintaining an exhaust pathway external to the catheter, to allow the native respiratory gas and the DLMW gas to flow in the proximal exhalation direction out of the lung area through the proximal feeding bronchus over the treatment period.