system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: When giving CPR, how can you give oxygen to the victim through breaths if what you're breathing out is CO2?





Edit: Thank you everyone for your explanations. It seems that its kind of split as to whether or not you give breaths during CPR. But as many have already mentioned, CPR as taught to lay people are instructed to do just chest compressions while rescue breaths should only be attempted by those who are trained and/or know what they're doing. However, one user pointed out that it really depends on the situations and, like it or not, peoples first instinct when giving CPR is rescue breaths whether trained or not. As for my original question about breathing out CO2, thanks to those that answered that! I didn't expect this to turn out to have so many comments. ALSO if anyone is seeking more information about CPR please see legitimate(while I know some of you are legitimate health care professional, you just never know with others) sources outside of reddit like your local Red Cross!
gpt
About 16% of the air you breathe out is oxygen.

But anyway, you don't need to give breaths when performing CPR.  It actually wastes time.  The chest compressions themselves will cause the lungs to inflate and deflate and thus draw in air.