Review of: Iwami T, Kawamura T, Hiraide A, et al: “Effectiveness of bystander-initiated cardiac-only resuscitation for patients with out-of-hospital cardiac arrest.” Circulation. 116(25):2900-2907, 2007.
The Science
This study, from Osaka Japan was prospective, population-based, observational study of consecutive cardiac arrest resuscitation from May 1, 1998 through April 30, 2003. This means the data was extracted from a database registry. The goal of the study was to determine if a difference exists between patients that received conventional CPR and those that received chest compression-only CPR. They measured ROSC, admission to hospital, hospital discharge and one-year survival.
During this time there were 24,347 adult out-of-hospital cardiac arrests. Resuscitation was attempted on 23,436, of which 13,444 were presumed to be of cardiac origin. Of these, 4,902 were witnessed and 783 (16%) received conventional CPR, 544 (11%) received chest compression-only CPR, and the remainder received no bystander CPR.
When the authors excluded the 864 arrests where it took EMS greater than 15 minutes to arrive, they discovered that the overall mortality and morbidity was the same for conventional and chest compression-only CPR. Both modalities were significantly better than no CPR. For arrests longer than 15 minutes no statistical difference existed between the two modalities, but the data was trending toward improved outcomes with conventional CPR.
The Street
This study made the headlines and essentially led the public to surmise that compression-only CPR was superior to conventional CPR. While that isn’t what the data showed, it does address the issue that appears to keep bystanders from performing CPR — performing mouth-to-mouth ventilation. However, if you look more closely at the data you’ll see that only 27% of the arrests received bystander CPR. Of those that didn’t get bystander CPR, the vast majority were witnessed cardiac arrests in the home.
I believe the data from this study is consistent with other studies showing compression-only CPR is at least as effective as conventional CPR. The question of whether establishing a patent airway enhances passive ventilation is yet to be definitively decided.
With that said, the bottom line is the survival rate from cardiac arrest is unlikely to exceed 10% unless we can get bystanders to start CPR. What we need now is to pilot compression-only CPR training and determine whether this increases the likelihood of bystanders performing CPR. We should concentrate our efforts on family members of at-risk patients since their arrests occur predominantly in the home.
