July 28, 2010 -- Bystanders who perform CPR on patients with suspected heart attacks can safely skip the rescue breathing -- typically called mouth-to-mouth resuscitation -- and just perform the chest compressions, according to two new studies.
''We feel comfortable saying chest compressions alone, when performed by a layperson, will provide at least the benefit that conventional CPR, with rescue breathing, will provide," researcher Thomas D. Rea, MD, medical director for King County, Wash., Medic One, tells WebMD.
The suggestion to skip the mouth-to-mouth part of CPR, he emphasizes, does not apply to emergency medical personnel, but only to laypeople who may be able to provide CPR after a suspected heart attack while waiting for professional medical help to arrive.
Rea's study, along with another head-to-head comparison of the two CPR approaches, is published in the New England Journal of Medicine.
''We are trying urgently, desperately, to make CPR more accessible to bystanders," Rea says, noting that performing CPR soon after a heart attack can increase the likelihood of survival twofold. Hopefully, he says, the finding that the rescue breathing is not crucial will make the technique simpler and perhaps more palatable for people.
CPR was first proposed about 50 years ago, when researchers suggested that external chest compression could provide blood circulation to the brain and heart after a heart attack. The mouth-to-mouth breathing was added later.
But in recent studies, researchers have focused on whether both components are always crucial. In 2008, the American Heart Association issued an advisory for the public, advocating hands-only CPR for bystanders not trained in CPR with rescue breathing.
CPR Techniques: The Studies
Rea's team evaluated 1,941 patients who had out-of-hospital heart attacks and were given CPR from bystanders being instructed by emergency dispatchers. Patients were randomly assigned to get either chest compression only or conventional CPR with rescue breathing.
The researchers looked at the percent in each group that survived to hospital discharge.
"We found that survival in the chest compression alone group was 12.5% and survival in the conventional CPR group was 11%," Rea tells WebMD.
Rea's study was supported in part by the Medic One Foundation and the Laerdal Foundation for Acute Medicine. In the second study, Swedish researchers evaluated 1,276 patients with suspected out-of-hospital heart attacks, assigning half to conventional CPR and half to compression-only.
The rate of 30-day survival was similar in the groups -- 8.7% of those getting compression-only CPR and 7% of those getting conventional CPR. The Stockholm County Council, SOS Alarm, and the Swedish Heart-Lung Foundation supported the study.
CPR, With and Without Mouth-to-Mouth: Other Views
The two new studies are good news for bystanders, some of whom have been reluctant to do the rescue breathing part of CPR, says Myron L. Weisfeldt, MD, chairman of the department of medicine at Johns Hopkins University School of Medicine, Baltimore, who wrote an editorial to accompany the studies.
Some bystanders worry about the risk of disease transmission in mouth-to-mouth resuscitation, he tells WebMD, although the risk has been shown to be low.
Based on the new studies, he says, "chest compression alone appears to be just as valuable as chest compression with rescue breathing." The new findings, he says, apply to adults with cardiac arrest.
The chest compression component, he suspects, is also easier for most people to perform than the mouth-to-mouth.
''For the consumer, this is important [news]," says Sumeet Chugh, MD, associate director of the Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles. ''Enough data has accumulated to say that bystander CPR positively impacts survival," he tells WebMD. Now, the finding that chest compression alone seems adequate is even better news, he says.
"It is a little awkward to do rescue breathing on someone you don't know," he says.
But, he says, those who go to a CPR course should still expect to be taught the rescue breathing technique, he says, as it may be needed in other situations.