Is it possible to fill human lungs with some liquid and viscouse substance which would allow only oxigen pass through it (easily), not any other atoms or molecules? I've read such experoments been conducted on mice who were capable to breath underwater with lungs filled with perfluorocarbone liquid. But what I'm looking for is to breath fresh air, not underwater.

The liquid would have to alot of oxygen in it, and would therefore need to efficiently dissolve the gas. Perlfluorocarbone liquids are oxygen-rich which is why they'd work.

Now you have a way of introducing oxygen into the body (at least theoretically), so how do you remove carbon dioxide, and remove it efficiently to avoid acidosis?