New Study Suggests That Compression Only CPR Is Better Than No CPR

A study by Gabriel Riva and his colleagues published in Circulation assessed the rates of different forms of cardiopulmonary resuscitation (CPR) during three different guideline periods. They showed that there was almost a two-fold increase in the rates of CPR before the arrival of emergency medical services (EMS) as well as a 6-fold higher rate of compression-only CPR (CO-CPR) over time. Additionally, any form of CPR was associated with doubled survival rates when compared to no CPR. These findings support the use of CO-CPR as an option in future CPR guidelines as it is associated with higher CPR rates and higher overall survival in out-of-hospital cardiac arrest when compared to no CPR.

CPR, which consists of repeated chest compression and rescue breaths, has been demonstrated to be a strong predictor of survival in out-of-hospital cardiac arrest (OHCA). The concept of compression-only CPR emerged as an alternative to standard CPR (S-CPR), as it was easier to teach, was associated with a higher rate of CPR and therefore, a higher rate of survival. The Swedish Register for Cardiopulmonary Resuscitation (SRCR) is a national quality register for reporting OHCA in Sweden. Using this SRCR, Dr. Riva and his colleagues used the identified all patients with a bystander witnessed OHCA between 2000 and 2017. These patients were then divided into three groups: (1) Patients with no CPR initiated before EMS arrival (No-CPR) (2) Patients who only received chest compression (CO-CPR) (3) Standard CPR consisting of rescue breaths and chest compression (S-CPR). The three different CPR guideline periods were defined as 2000-2005, 2006-2010 and 2011-2017. In the study, a total of 30,445 cases were analyzed. Of those, 40.0% received no CPR, 39.2% received standard CPR and 20.8% received compression only CPR. The patients who did not receive CPR had the highest median age, highest proportion of women and highest proportion of arrests occurring at home. Additionally, the median EMS response time was different between the three groups with the response time being 7 minutes in the no CPR group, 10 minutes in the standard CPR group and 8 minuets in the compression only CPR group.

As compared to the first time period (2000-2005), the proportion of patients that received any form of CPR has increased from 40.8% to 58.8% in the second period to 68.2% in the third period. The proportion of patients who received standard CPR changed from 35.4% to 44.8% to 38.1%. Finally, the proportion who received compression only CPR increased from 5.4% in the first period to 14.0% to 30.1%. Amongst the three groups, standard CPR had the highest 30-day survival rate (13.8%), followed by compression only CPR (13.5%) and finally, no CPR (5.8%). When compared to no CPR, after adjusting for differences in baseline characteristics, the adjusted odds ratio was statistically significant in the standard CPR group (OR 2.6; 95% CI 2.4-2.9) and the compression only CPR (OR 2.0; 95% CI 1.8-2.3). When comparing standard CPR to compression only CPR, there was no statistically significant difference in the overall 30-day survival (OR 1.03; 95% CI 0.94-1.13). However, the difference between the two groups became statistically significant after adjusting for baseline variables (OR 1.2; 95% CI 1.1-1.4).

While the data suggests that both CO-CPR and standard CPR are associated with a higher survival rate, the neurological function is an important outcome to consider. The European guidelines, which were last updated in 2017, recommend that all bystanders perform chest compression in cases of cardiac arrest, and that “those bystanders who are trained, able, and willing to give rescue breaths and chest compressions do so for all adult patients in cardiac arrest”. However, there is a well-recognized evidence gap in knowledge in regards to the effectiveness of CO-CPR when compared to standard CPR. A randomized trial would be needed to compare outcomes of standard and compression-only CPR. Currently, there is an ongoing randomized controlled trial in Sweden (clinical trials number NCT02401633) that hopes to address this gap.