As far as liability, Ohio has a good samaritan law, IE: if you`re not a liscanced doctor or nurse and you stop to help because there`s no one else to do so you can`t be sued for screwing up. Better to try to help and break a rib doing CPR than to do nothing and watch someone die.
In Ohio, perhaps. In other states, the good samaritan law applies only to first responders, not lay people.
Statistics show that CPR performed by lay people is usually ineffective.