Someone suffering cardiac arrest ‘in the street’ may be more likely to survive if a layperson who attempts cardiopulmonary resuscitation (CPR) leaves out the rescue breaths altogether and just concentrates on chest compressions, suggest the authors of US research in this week’s JAMA.
As evidence increased for the importance of uninterrupted chest compressions for CPR after a heart attack, authorities in Arizona, US began a public education campaign in 2005 that encouraged laypeople to use chest-compression-only CPR (COCPR), especially as it is also easier to learn and perform than conventional CPR with rescue breathing.
Researchers in Phoenix, Arizona have now compared outcomes in 4415 adults who suffered a cardiac arrest away from hospital during the five years beginning January 2005: 2900 were given no CPR at all by bystanders, 666 were given conventional CPR with rescue breaths and 849 had COCPR.
They found that the likelihood of a bystander performing any kind of CPR increased from 28.2% in 2005 to 39.9% in 2009. And over time, CPR became increasingly likely to be COCPR rather than conventional CPR – it accounted for 19.6% of all CPR attempts in 2005 but 75.9% by 2009.
Over the same period, rates of survival to hospital discharge more than doubled, from 3.7% to 9.8%. There was a marked difference in survival between the three groups. Just 5.2% of people who had received no bystander CPR survived to hospital discharge, compared with 7.8% who had had conventional CPR and 13.3% for COCPR. The authors found on further analysis a roughly 60% improved odds of survival for COCPR compared with conventional or no bystander CPR.
The authors suggest several reasons for the apparent survival benefit of COCPR compared with conventional CPR, including: forward blood flow deteriorates rapidly during even brief disruptions of chest compressions; adequate blood flow takes a long time to return after resuming chest compressions; conventional CPR is complex; and breaths take a significant time to perform.
The author of an accompanying editorial, David C. Cone from Yale University School of Medicine, says that these results and those from other studies that suggest a survival benefit for COCPR should encourage further investigations into the method.
“In the meantime, physicians and other health care professionals involved in resuscitation should look to the new [CPR] Guidelines 2010 documents for the international consensus on the science of compression-only CPR, and should look to new-curriculum CPR classes that will follow as opportunities to encourage the general public to learn this simple and potentially lifesaving skill.”