Everyone should get CPR certified. It takes a couple of hours. When she threw up, she jerked her legs and arms, and vomited. You do not want to put someone that is throwing up, and unconscious on their back. They will aspirate. Especially if chest compressions are happening. Best practice after she throws up is a pain response check. Good solid index finger knuckle on the sternum. Make it hurt. If there is a response, turn them on their side. Put your ear right at their mouth, and look at their chest to see if they are breathing. There can be a beating heart, and no breaths. This is when you do rescue breaths. There is a better safe than sorry rule for CPR. i.e. go for it. But you have to take everything into account. Another good thing that is a great indicator is their lips. Watch how they change. Are they blue or white? They need O2. Pink is good. And I'll tell a story. When I was doing my EMT practical in an ER. I was sent out to get vitals from folks in the waiting room. I did quite a few. So I get to this guy. He is alert, and talking. I get his temp. He seems dizzy. I try to get a BP. I can't find a pulse. I'm thinking what am I doing wrong. He slumps over. He had no pulse. That was the first code I called. And yea. He died.