An implantable medical device is described. The implantable medical device includes an anti-condensation filler that is highly permeable to a predetermined class of small molecules, such as oxygen. The implantable medical device includes a small molecule discharge bag that is permeable to the small molecule, and a cannula that connects an interior of the small discharge bag to the anti-condensation filler. In operation, small molecules are collected and transported through the anti-condensation filler to the cannula for diffusion through the small molecule discharge bag. Even when this device is implanted in a high humidity and temperature gradient environment, the anti-condensation filler prevents condensation, such as water condensation.
