Physicians from around the country participated in a 5-year study to evaluate CPR taught to the general population and medical personnel. They concluded that patients had increased survival with compression-only CPR. Only 30% of patients needing CPR get it. Avoiding the mouth-to mouth guideline increased the percentage of patients receiving CPR. For those who did get either kind of CPR, survival of patients was in the 10-20% range, but it was better when compression was not mixed with breathing for the patient, if intubation was not available. The best action is to compress vigorously at 100 times per minute until the patient can be shocked by a portable defibrillator.
See JAMA, October 6, 2010—Vol 304, No. 13, 1447-1455.