Surviving a Cardiac Arrest

CPR from bystanders associated with an increase in cardiac arrest survival in new study

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh
For people who suffer from cardiac arrest, a stranger's knowledge may be one of the primary factors determining their chances of survival.

A recent study looked at survival rates of cardiac arrest and bystander CPR rates in Denmark, which recently implemented several programs to improve responses to cardiac arrest.
The researchers found that a bystander performing CPR after a person goes into cardiac arrest was associated with improved chances of survival upon reaching the hospital, after 30 days, and after one year.
Although the data showed the results of a number of factors affecting cardiac arrest survival rates, there is a strong correlation between bystander CPR and increased chances of survival.

"Attend a CPR training course."

Mads Wissenberg, MD, of the Department of Cardiology in Copenhagen University Hospital Gentofte, led the study to see the effects of bystanders performing CPR on cardiac arrest survival rates.
Cardiac arrest occurs when the heart stops beating and pumping blood through the body. It can be caused by many risk factors and diseases. Cardiac arrest can be treated, but it often leads to death, as blood is needed to provide the body with oxygen.
Cardiac arrest refers to an event when the heart stops contracting or is in such an irregular or weak rhythm that blood is not effectively pumped within the body to sustain life.  Heart attacks, caused by blocked arteries to the heart muscle, can be one of many causes of cardiac arrest.
When a person experiences cardiac arrest, one of the first methods of treatment may be cardiopulmonary resuscitation, or CPR.
To perform CPR, a person must provide at least 100 chest compressions per minute. The person performing CPR may also push air into the lungs of the person suffering from cardiac arrest by breathing into their mouth or nose, or by using a respiration device.
CPR is a way to manually circulate blood throughout the body until a person can receive medical attention.
To see how effective CPR and CPR education were at increasing survival chances among people who suffered from cardiac arrest, this study looked at data from the Danish Cardiac Arrest Registry, where EMS personnel log instances of out-of-hospital cardiac arrests.
The researchers used data between 2001 and 2010 of 19,468 patients who experienced cardiac arrest due to heart problems outside of a hospital and who were not around emergency medical services personnel when the incident occurred. The average age of the patients was 72 years, and 67.4 percent were men.
The study used this time period, because between 2001 and 2010, Denmark implemented several guidelines and education programs for CPR. Mandatory CPR training was implemented in elementary schools and for people acquiring a driver's license over this time.
The authors of the study estimated that about 15 percent of the Danish population took a CPR training course between 2008 and 2010.
The researchers looked at data on whether a bystander had witnessed the cardiac arrest, whether they performed CPR, whether the subject had regained a heart rhythm, and the subjects' survival rates after the incident.
The study found that, from 2001 to 2010, the rate of bystander CPR rose from 21.1 percent of the cardiac arrests to 44.9 percent. Moreover, survival rates of cardiac arrest at 30 days and one year after the incidents tripled.
Additionally, from the beginning to the end of the data period, patients who were alive upon arrival to the hospital increased from 7.9 percent to 21.8 percent. 
The authors suggest that there are multiple factors behind the improvement in cardiac arrest care. Better CPR training and stronger emergency responses may be reasons for the increased survival rate.
According to Chris Galloway, MD, who is Board Certified in Emergency Medicine, "While out of hospital survival for cardiac arrest remains low and will never approach the crazy expectations set forth by medical shows on TV, the most critical interventional time to increase survival is at the time of occurrence. Bystander CPR and AED's (Automated External Defibrillator) offer the best chances for the patient while the 911 system is activated to get the patient to the hospital. It is amazingly gratifying to help save someone's life and with our aging population, bystander witnessing of cardiac arrest is becoming a more common occurrence. Get CPR certified!"
The researchers noted that survival rates remained low for people who did not receive bystander CPR. Although the study design does not allow for drawing causal conclusions, the correlation between bystander CPR rates and survival rates is strongly supported by the data.
This study was published on October 1 in JAMA.
The research was funded by the Danish foundation TrygFonden, the Danish Heart Foundation, and the Health Insurance Foundation. Several of the authors reported conflicts of interest including board membership with TrygFonden, grants, and compensation for speaking.
Review Date: 
September 27, 2013
Last Updated:
October 2, 2013