Part of the motivation is to avoid having to cut into neck and throat, keeping in mind that I'm just an armchair observer.
Apparently they have to do traciotomy if injuries or surgical area prevents using tube through the mouth.
Maybe there is possibility of sending nano-sized devices into the body, assuming more advancement has to take place. You send in your agent-nanobot, with 2 oxygen atoms, it releases the O2 inside, then exits the body. Probably terribly naive of course.
First thought was a 'sugar' with the O2 attached, then they separate and the 'sugar' gets absorbed, rather than somehow getting out of the body.
Very naive, as I suppose simply an O2 molecule needs to be binding with some carrier molecule in the blood, rather than a simple dissolved gas, thats almost a mini-bubble.
I believe that's embolism which isn't good.
From SCUBA diver class we learned that dissolved gas is bad, maybe can cause stroke.
Just speculating, as science advances might enable processes, internally, rather than the 'hooked up to big machine' type approach.
Either those 'carriers' I'm suggesting would be exiting (the body) or would become metabolized ? I suppose they can't just 'dump' an O2 molecule into blood somewhere.
Good place to start, (for my own understanding) would be study the lungs and processes there.