"Volunteer SAR-ship crewmember here; when you suspect whoever is lying down is not breathing by themselves, begin CPR immiditially AND DO NOT STOP until medical professional arrives, even if this means that you have to go on for several hours. We do not perform CPR to have the patient miraculously wake up and make out with us, we do this to sustain the most vital bodily function - the circulation of oxygen to the brain - until we can get that person to a hospital."