Well that's what I was about to point out... By inncorect head positioning you pump stomach full of air and than eventually all the stuff comes up... About 90% of my cardiac arrests are messy. My latest one which was a save happened to be a gentelman with stomach ultcer bleeding for days. When fireman pressed on his chest there was a fountain of half digested blood that went about 2-3 feet in the air. I dont know how hard core you are but I wouldnt recommend putting your mouth on that.

HIV doesnt worry me as much as Hep B. Well I had a shot for it but that's not somethign that typical bystander will have.

I'm all for making cpr simple for a layman. But medical professional should be thought differently.