Two new studies conclude that mouth-to-mouth resuscitation is not nearly as important as chest compressions when it comes to bystanders saving the life of someone in cardiac arrest.
The studies, both published in the New England Journal of Medicine, provide clear evidence that non-medically-trained people can save lives using the simpler form of "hands only" CPR.
Two years ago, the Heart and Stroke Foundation followed the lead of the American Heart Association in promoting "hands-only" CPR for most bystanders who find adults in cardiac arrest.
The change in approach came amid research that found that adults needing CPR get it only about one-quarter to one-third of the time.
It's estimated that only about six to eight per cent of people who go into cardiac arrest outside a hospital survive. But both studies found that survival rates rose when bystanders did dispatcher-directed, hands-only CPR.
One of the new studies, carried out in London and the Seattle area, involved more than 1,900 people who witnessed someone in cardiac arrest and called for help. Emergency dispatchers instructed callers to do either hands-only CPR or standard CPR.
The second study was similar but done in Sweden with nearly 1,300 participants.
In both studies, most of the patients died, no matter what form of CPR they received. But in the Swedish test, the 30-day survival rate was slightly better for those who didn't get rescue breathing: 7 per cent with rescue breathing and 8.7 per cent without.
In the larger study, when bystanders did chest compressions alone, it slightly increased a patient's chance of leaving the hospital without brain damage:
• 11.5 per cent escaped brain damage through standard CPR
• 14.4 per cent escaped brain damage with chest compressions alone
The new studies should encourage dispatchers and bystanders to be more aggressive about telling bystanders to use the simpler technique.
The larger study found that when the 911 dispatcher told the caller to start CPR, 80 per cent were willing to attempt it when given hands-only instructions. That was higher than the 70 per cent who were willing to attempt the standard version.
The standard version used to call for two quick breaths for every 15 chest compressions. That changed in 2005 to two breaths for every 30 compressions. The "hands only" version calls for not stopping chest compressions at all for the mouth-to-mouth breaths.
Many are reticent to try standard CPR because it can be confusing. It requires tilting the victim's head back, clearing the airway, pinching the nose, covering the mouth completely and blowing in.
Many people panic, worry that they can't do it right, and instead choose to stand aside and wait for help to arrive.
Traditional CPR is still the preferred form of resuscitation for someone who has stopped breathing because of choking, drowning or other respiratory problems. It's also the best method for children in cardiac arrest, who need the oxygen that rescue breathing provides.
In an accompanying commentary in the NEJM, Dr. Myron Weisfeldt of Johns Hopkins School of Medicine in Baltimore said CPR courses should continue to teach rescue breathing.
"It is important in cases of cardiac arrest due to obvious respiratory failure, which include most cardiac arrests in children and in some adults," he wrote.
