Each year, approximately 295,000 persons in the United States experience an out-of-hospital cardiac arrest (OHCA). Approximately 92% of persons who experience an OHCA event die.
An OHCA is defined as cessation of cardiac mechanical activity that occurs outside of the hospital setting and is confirmed by the absence of signs of circulation. Whereas an OHCA can occur from non-cardiac causes (i.e., trauma, drowning, overdose, asphyxia, electrocution, primary respiratory arrests, and other non-cardiac etiologies), the majority (70-85%) of such events have a cardiac cause.
This landmark report is based on a review of of 31,689 OCHA cases of presumed cardiac etiology (October 1, 2005 and December 31, 2010) in the Cardiac Arrest Registry to Enhance Survival (CARES) Registry. Results indicate:
- The mean age of victims is 64 years old
- 61% were male
- The survival to hospital discharge rate was 9.6%
- 36.7% of cases were witnessed by a bystander
- 33% received bystander CPR
- 3.7% were treated by a bystander with an automated external defibrillator (AED)
The majority of persons who experience an OHCA event, irrespective of etiology, do not receive bystander-assisted cardiopulmonary resuscitation (CPR) or other timely interventions that are known to improve the likelihood of survival to hospital discharge (e.g., defibrillation). Because nearly half of cardiac arrest events are witnessed, efforts to increase survival rates should focus on timely and effective delivery of interventions by bystanders and emergency medical services (EMS) personnel.
"Provision of optimal care at the scene is essential to survival," according to principal investigator, Byran McNally, MD, of Emory University, and colleagues. "If a pulse is not restored before EMS transport, additional efforts at the receiving hospital almost invariably fail."
This is the first report to provide summary data from an OHCA surveillance registry in the United States. The CARES program is a collaboration of Emory University and the Centers for Disease Control and Prevention. Sites in 20 states currently participate in the program.
The CARES data is consistent with data from the American Heart Association. Here's a summary of key stats:
- 295,000: Annual incidence
- 8-9.6%: Rate of survival to hospital discharge
- 5,760: Annual incidence in youth <18
- 6%: Rate of survival to hospital discharge in youth <18
- 64: Mean age of victims
- 61%: Proportion of victims who are male
- 36.7%: Proportion of cases witnessed by a bystander
- 31-33%: Proportion of OCHA victims who receive CPR
- 2-3.7%-: Proportion of OCHA victims who are treated with an AED before EMS arrival
 Lloyd-Jones D., et al. Heart Disease and Stroke Statistics 2010 Update: A Report from the American Heart Association, Circulation published online Dec. 2009, DOI: 10.1161/CIRCULATIONAHA.109.192667
 McNally, B., et al. Out-of-hospital cardiac arrest surveillance: Cardiac Arrest Registry to Enhance Survival (CARES): United States, October 1, 2005-December 31, 2010. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report. July 29, 2011, 60(SS08);1-19.
By Mary Newman