NEJM: More evidence supports compression-only CPR by bystanders
Swedish researchers have found no difference in 30-day survival when witnesses to cardiac arrest performed either compression-only cardiopulmonary resuscitation (CPR) or standard CPR, which consists of chest compressions and ventilation, according to a study in the July 29 New England Journal of Medicine.

"Overall, this study lends further support to the hypothesis that compression-only CPR, which is easier to learn and to perform, should be considered the preferred method for CPR performed by bystanders in patients with cardiac arrest," the authors concluded.

Leif Svensson, MD, PhD, and colleagues from the Karolinska Institute in Stockholm, Sweden, led an effort that prospectively randomized patients with suspected, witnessed, out-of-hospital cardiac arrest (OHCA) to undergo either compression-only CPR or standard CPR (two ventilations alternating with 15 compressions). Witnesses to the OHCA received CPR instructions from emergency medical dispatchers

The primary endpoint was 30-day survival. The secondary endpoints were one-day survival, the first detected cardiac rhythm and survival to discharge from the hospital.

A total of 1,276 patients from Sweden were randomized: 620 to compression-only CPR, 656 to standard CPR. Researchers found no significant differences between the two groups for the primary and secondary endpoints.

Additionally, they found no significant differences in primary or secondary outcomes among the subgroups studied: age, interval between call and first EMS response or first cardiac rhythm.

The authors noted that the American Heart Association (AHA) guidelines call for the two breaths after 15 chest compressions to have a duration of only 1.5 to 2 seconds. Studies, however, have found durations of 16 seconds on average.

"It is very difficult for a layperson to provide adequate ventilation," they wrote. "Studies also have shown that both laypersons and health workers hesitate to initiate CPR that includes mouth-to-mouth ventilation, for reasons of health and safety."

The AHA and European Resuscitation Council guidelines have recently changed to emphasize compresson-only CPR for OHCA. Svensson and colleagues concluded that their study, which shows no difference in survival, reinforces compression-only instructions for bystanders performing CPR prior to the arrival of emergency personnel.