[semi-extrinsic]

Nitpick (on TFA): perfluorocarbons are not "a liquid form of O2". The thing about these liquids is that they can dissolve a huge amount of both O2 and CO2, compared to normal liquids. It's kinda crucial that they can carry lots of CO2 out of the body as well.

Calling PFCs "a liquid form of O2" is like saying carbonated water is "a liquid form of CO2".

[amelius]

But how do you replenish this once the O2 is absorbed? Do you pump out the delivery agent, then pump the O2-rich form back in?

[kazinator]

Obviously; and--I would hope!--out the same end where it came in.