Cardiopulmonary resuscitation using only chest compression is more lifesaving than standard CPR when performed by nonprofessionals, possibly because of its simplicity, according to an article published online Oct. 15 in the Lancet.
In the United Kingdom, compression-first CPR already is the standard recommendation for treating sudden adult cardiac arrest; guidelines since 2005 have reduced (though not eliminated) the recommended amount of mouth-to-mouth or mouth-to-nose ventilation from earlier recommendations. The current findings add weight to the case for compression-only CPR without any rescue ventilation as the default for nonprofessional bystanders confronted with a cardiac arrest.
For their research, Dr. Michael Hüpfl of the department of anesthesiology at the Medical University of Vienna and his colleagues performed a meta-analysis pooling data from three randomized trials, and analyzed results for 3,031 patients. They found that chest-compression-only CPR performed by bystanders under directions from a telephone dispatcher was associated with an improved chance of survival compared with standard CPR performed by the same (14% vs. 12%) in adult patients experiencing cardiac arrest outside a hospital. The absolute increase in survival was 2.4%, with the relative chances of survival increased 22% by chest compression–only CPR (Lancet 2010 [doi:10.1016/S0140- 6736(10)61454-7]).
In a secondary meta-analysis of seven observational cohort studies, the researchers saw no significant difference between the compression-only and standard CPR arms.
Compression-only CPR, the investigators concluded, should become the default instructions for dispatchers to give to bystanders. “The pooled effect size of about 22% might seem small, but rates of survival after out-of-hospital cardiac arrest have been about 4%-8% for the past few decades, so our result could represent important progress,” they wrote in their analysis.
The reason for the relative success of compression-only CPR, the researchers wrote, may lie in its simplicity to perform. “By avoidance of rescue ventilation during CPR, which is often fairly time consuming for lay bystanders, a continuous uninterrupted coronary perfusion pressure is maintained, which increases the probability of a successful outcome. These considerations were the main reason to increase the compression-to-ventilation ratio for standard basic life support from 15:2 to 30:2 in the 2005 resuscitation guidelines.”
Already, in advance of the Lancet article, the Resuscitation Council UK, which makes CPR guidelines widely followed in the United Kingdom and in Europe, had new guidelines for bystanders in the works that do away with the recommendation for rescue ventilation.
Dr. Jerry P. Nolan of the Royal United Hospital NHS Trust in Bath, England, and an author of existing Resuscitation Council guidelines, said in an interview that the council’s new guidelines, scheduled to be published Oct. 18, were somewhat coincidental to the Lancet article – but that the coincidence was fortuitous.
“The guidelines went ahead on less strong data, but this really seals it,” said Dr. Nolan, who contributed editorial comment on the findings in the Lancet. “If people have not been trained, they should be no doubt doing compression only. The act of stopping compression [to ventilate] most certainly leads to long delays.”
In cases of adult cardiac arrest where a trained professional is on the scene, standard CPR with ventilation remains preferable, Dr. Nolan said, noting that compression-only CPR “works for only about the first 4 or 5 minutes. The whole thing comes down to what is ideal for the bystander’s level of training.”
In terms of improving the general public’s ability to provide a first response in cases of cardiac arrest, Dr. Nolan said he had great hope for compression-only CPR. “In the U.K. right now in about 30% of [cardiac arrest] cases, someone attempts CPR,” he said. “What we would like to see is a big increase in the number of bystanders that are prepared to do CPR. A good percentage of people will benefit.”
Dr. Nolan said that he expects that CPR guidelines throughout Europe and the United States will soon be updated to reflect the compression-only emphasis.
Dr. Hüpfl and his colleagues’ study was funded by the National Institutes of Health and the American Heart Association. Coauthor Dr. Peter Nagele disclosed that his institution, Washington University in St. Louis, had received research support from Roche Diagnostics, unrelated to the study, and that he had received consultancy fees from Gerson Lehrman Group. Another study author, Dr. Harald F. Selig, reported receiving a salary from St. John’s Ambulance Service, Vienna, and other support from Novo Nordisk.
Dr. Nolan and his coauthor on the editorial, Dr. Jasmeet Soar of the North Bristol (England) NHS Trust, declared no conflicts of interest.