For cardiac arrest CPR performed by laypersons, chest compression-only may lead to better outcomes

Out-of-hospital cardiac arrest is a major public health problem, affecting approximately 300,000 individuals in the United States annually. Although survival rates vary considerably, outcomes can be improved with bystander CPR. In 2005, a statewide program was established in Arizona aimed at improving survival. "These efforts included changes in the approach to the care provided by both bystanders and emergency medical services (EMS) personnel and were based on the increasing evidence in favor of minimizing interruptions in chest compressions during CPR," the authors write. A multifaceted effort was launched to encourage bystanders to use compression-only CPR (COCPR) because this approach is easier to teach, learn, remember, and perform than conventional CPR with rescue breathing, according to background information in the article.

Bentley J. Bobrow, M.D., of the Arizona Department of Health Services, Phoenix, and colleagues evaluated whether widespread endorsement of COCPR for adult sudden cardiac arrest would be associated with an increased likelihood that lay rescuers would perform CPR and an increased likelihood of survival to hospital discharge compared with no bystander CPR and conventional CPR. The study included patients at least 18 years old with out-of-hospital cardiac arrest between January 2005 and December 2009 in Arizona. A total of 4,415 adults with out-of-hospital cardiac arrest met all inclusion criteria for analysis, including 2,900 who received no bystander CPR, 666 who received conventional CPR (15.1 percent), and 849 who received COCPR (19.2 percent).

The researchers found that rates of survival to hospital discharge were 5.2 percent for the no bystander CPR group, 7.8 percent for conventional CPR, and 13.3 percent for COCPR. The annual rate for lay rescuers providing any type of bystander CPR increased significantly over time, from 28.2 percent in 2005 to 39.9 percent in 2009. "Among patients who received bystander CPR, the proportion with COCPR increased significantly over time, from 19.6 percent in 2005 to 75.9 percent in 2009. Overall survival also increased significantly over time: from 3.7 percent in 2005 to 9.8 percent in 2009." Further analysis indicated that COCPR was associated with an approximately 60 percent improved odds of survival compared with no bystander CPR or conventional CPR.

The authors add that there are multiple reasons COCPR may have advantages over conventional CPR techniques, including the rapid deterioration of forward blood flow that occurs during even brief disruptions of chest compressions, the long ramp-up time to return to adequate blood flow after resuming chest compressions, the complexity of conventional CPR, the significant time required to perform the breaths, and the critical importance of cerebral and coronary circulation during arrest.

Editorial: Compression-Only CPR -- Pushing the Science Forward

In an accompanying editorial, David C. Cone, M.D., of the Yale University School of Medicine, New Haven, Conn., writes that the findings of this and other studies suggesting a survival benefit for compression-only CPR should encourage and justify continuing investigations involving this CPR 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."