He didn't ask, because anyone with a clue (that's not you) and who's done CPR with a LUCAS and ET tube knows you can actually deliver TOO MUCH oxygen doing CPR.
But, but, but.........google never came up with anything like that.
Well, I learned about oxygen toxicity by doing CPR a few hundred times, not google, so I'm sure no-elk will find some "fact" on google that "proves" something that makes me a communist.......