Article Text

Cohort study
Another step towards the acceptance of chest compression only CPR for primary cardiac arrest
  1. Gordon A Ewy
  1. Department of Medicine, University of Arizona College of Medicine, Tucson, Arizona, USA
  1. Correspondence to: Dr Gordon A Ewy
    Department of Medicine, University of Arizona College of Medicine, 1501 North Campbell Avenue, Tucson, Arizona 85724, USA; gaewy{at}

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Implications for practice and research

  • Out-of-hospital cardiac arrest (OHCA) is a major public health problem.

  • For decades, guidelines prescribed mouth-to-mouth (MTM) ventilation as the first step in resuscitation of both primary and secondary cardiac arrest.

  • The report by Iwami and associates is another observational study in patients that found improved survival of patients with primary OHCA who received chest compression only cardiopulmonary resuscitation (CO-CPR) by bystanders.1


Bystander-initiated MTM ventilation alternating with chest compressions was initially the standard, and has been in the guidelines for bystander CPR for patients with cardiac arrest for a half century. Two decades of research in our physiological laboratory at the University of Arizona Sarver Heart Center led us to conclude that CO-CPR improved survival of patients with primary cardiac arrest.2 ,3 Between 2005 and 2010, advocating and teaching CO-CPR for bystanders of patients with primary OHCA in Arizona resulted in improved survival of patients with witnessed arrest and a shockable rhythm from 17.7% to 33.7%.4 However, most countries have not adopted this approach.


Iwami and associates analysed the outcomes among 1376 OHCA patients in a prospective, nationwide, population-based cohort study of OHCA victims in Japan in whom an automatic external defibrillator (AED) was used by lay bystanders who provided bystander CPR.1 Accordingly, these patients were a subset most likely to have a primary cardiac arrest.


Survival was better in the group who received CO-CPR by bystanders. Among them, 506 (36.8%) received CO-CPR and 870 (63.2%) received conventional CPR. The CO-CPR group (40.7%, 206 of 506) had a significantly higher rate of 1 month survival with favorable neurological outcome than the conventional CPR group (32.9%, 286 of 870; adjusted OR 1.33; 95% CI 1.03 to 1.70).1


Their results, improved survival in those who received CO-CPR, were even more significant, for in Japan 1.6 million citizens/year participated in the bystander CPR training programmes consisting of chest compressions plus MTM ventilation and AED use.1 During the time of this study, CO-CPR was not officially advocated. In fact, during the 5 years of this study in Japan, their emergency telephone dispatchers were basically trained and ordered to give CPR instruction with conventional CPR.1 Nevertheless, the incidence of bystander CO-CPR increased from 5% in 2004 to 44% in 2009!1

This is another report of a CPR technique that has been advocated by national and international guidelines for decades, a technique in which thousands of man hours have been spent demonstrating and millions of dollars spend on education, is less effective than a technique that until recently has not been endorsed, advocated nor taught.5

Unfortunately, the long road to the acceptance of CO-CPR for bystanders has not as yet reached its destination. Hopefully reports such as that of Iwami and associates will help those responsible for guidelines worldwide to reach the right conclusions—that CO-CPR should be advocated for patients with primary OHCA. That primary cardiac arrest be taught as an unexpected witnessed (seen or heard) collapse in an individual who is not responsive.2 And that MTM ventilation plus chest compressions should be reserved for respiratory arrests. But even in this subset of patients, the optimal ratio of ventilation to compressions is unknown and should be the subject of additional investigations.


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  • Competing interests None.

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