I'm not sure if I missed something but I like to think I'm reasonably clued up on diving matters. Whilst recently reading a book, it made the claim that the scene in “The Abyss” where the divers breathe liquid “air” was in fact based on real technology?! The film was released in 1989 and was quickly a cult diving film. If you are reading this and have not seen it shame on you! .
The technology is called “Total Liquid Ventilation” (TLV). This technology has been around from the late 1960s when a scientist Leyland C Clarke kept a mouse alive for several hours submerged in an Oxygenated perfluorocarbon. Recently TLV has been developed to help premature babies whose lungs are more used to fluids than gases. Supposedly the US Military are developing it for use with their deep diving teams where it allows longer bottom times than “traditional” heliox and trimix and because there is no air to compress it would theoretically allow divers to ascend and descend without decompression stop just like on The Abyss mentioned above.
The potential applications don’t stop there. NASA and the US Air Force (and maybe others) have discovered that pilots equipped with a TLV system could endure far higher G-forces as those forces are spread more readily through a liquid than the gas normally found in their lungs. For more information visit the Wikipedia page on liquid breathing.