The study found prompt CPR from bystanders saved lives and lessened the chance of brain injury in victims of cardiac arrest.
Sudden cardiac arrest - a condition that kills around 200,000 Americans a year - is where the heart stops pumping blood around the body. The most common reason is an irregular heart rhythm caused by ventricular fibrillation (VF).
Once the heart stops beating it is a race against time. The priority is to get it pumping again to restore blood and oxygen supply - particularly to the brain. The longer it remains without oxygen, the higher the chances of permanent injury and death.
CPR - cardiopulmonary resuscitation - is an emergency procedure to manually pump blood through the heart and the body in a person in cardiac arrest. Its purpose is to preserve brain function while waiting for medical attention to restore circulation and breathing.
In the Journal of the American Medical Association, researchers led Dr. Carolina Hansen of the Duke Clinical Research Institute in Durham, NC, review the effect of a state-wide program in North Carolina to increase bystander and first responder assistance to people who suffer sudden cardiac arrest.
The program - called The HeartRescue Project - delivered public training in schools and hospitals and also at major events such as State Fairs. It also offered additional instruction for emergency services about optimal care for patients in cardiac arrest.
Bystanders were encouraged to perform chest-compression CPR - without the need for mouth-to-mouth resuscitation.
The project also encouraged the use of automated external defibrillators (AEDs - machines that deliver an electric shock to get the heart back into rhythm) while waiting for the ambulance.
More survivors with less brain injury
The study used data on out-of-hospital cardiac arrests in urban, suburban, and rural communities in North Carolina from 2010 to 2013 - the same period over which the program rolled out across the state. There were two significant findings.
The first significant finding was that the proportion of patients who received CPR initiated by ordinary bystanders and who also received defibrillation from first responders rose from 14.1% in 2010 to 23.1% in 2013. This increase was also linked to greater likelihood of survival.
The second significant result was an increase in the proportion of survivors with less brain injury following cardiac arrest, and that bystander-initiated CPR was tied to this increase.
The data covered 4,961 cases that were tracked through a national registry that records cardiac arrests occurring outside of hospitals.
The registry includes information about the responses of bystanders and first responders, and the emergency services. It also records how well patients fare. First responders include firefighters, police officers, lifeguards and others who arrive on the scene ahead of the ambulance.
Dr. Hansen says they were surprised to see that survival increased only for those who received bystander-initiated CPR, compared with those who did not receive bystander initiated CPR, and notes:
"This suggests that the very earliest intervention is crucial, and is something anyone can do. It saves lives."
The HeartRescue Project is working to place more portable AEDs in public places so they can be used promptly by ordinary members of the public as well as trained first responders.
Medtronic Philanthropy, who fund the project, helped finance the study.
Meanwhile, Medical News Today recently reported a study led by the Cedars-Sinai Heart Institute that found black people have a higher risk of sudden cardiac arrest than white people. In the journal Circulation, the researchers describe how they analyzed 2002-2012 data from the metropolitan area of Portland, OR, and found the rate of sudden cardiac arrest among black residents was double that of white residents.