The benefits of mouth to mouth or rescue breathing are real and well documented. However, the importance in respect to chest compressions are not as important. To answer the question the ration is 30:2 chest compressions:breaths, with rescue breaths done first. I personally saved a mans life with just chest compressions and an AED. My cpr instructor taught that chest compressions were the most important and it was, because the person who went into cardiac arrest is back at the gym.

