The idea of breathing one of these heavily oxygenated liquids has been around for a while and I believe even tested on live animals. I can’t remember if it was tested on humans.

In theory it all works and has great benefits for breathing in high pressure environments. In reality I believe the issues encountered were: getting past the feeling of drowning at the beginning, needing very strong lungs for even normal breathing rates, and then transitioning back to air being problematic.