Survival After Cardiac Arrest Five Times Higher in Some Cities than Others: EMS May Be Key

EMS-treated cardiac arrest survival ranged from 3.0% to 16.3%; ventricular fibrillation survival ranged from 7.7% to 39.9%

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Sept. 24, 2008 – When hit with cardiac arrest your chances of survival are five times greater in some cities than others, which researchers say proves this often lethal event is treatable and that quality EMS services may be under-appreciated.

Approximately 166,000 to 310,000 Americans per year experience an out-of-hospital cardiac arrest (OHCA), although resuscitation is not attempted in many of these cases.

Graham Nichol, M.D., M.P.H., of the University of Washington, Seattle, and colleagues conducted a study to determine whether cardiac arrest incidence and outcome differed across geographic regions. Their goald was the identification of effective interventions that are used in some communities but have not been implemented in others.”

The study included data on all out-of-hospital cardiac arrests in 10 North American sites (8 U.S. and 2 Canadian) from May 2006 to April 30, 2007, followed up to hospital discharge, and including data available as of June 28, 2008.

Cases were assessed by organized emergency medical services (EMS) personnel. The ten sites were participants in the Resuscitation Outcomes Consortium, and were located in: Alabama; Dallas; Iowa; Milwaukee; Ottawa, Ontario; Pittsburgh; Portland, Ore.; Seattle; Toronto; and Vancouver, British Columbia.

Among the 10 sites, with a total population of 21.4 million for the areas studied, there were 20,520 cardiac arrests assessed by EMS personnel, according to the report in the September 24 issue of Journal of the American Medical Association.

Resuscitation was attempted in 11,898 cases (58.0 percent of total); 2,729 (22.9 percent of treated) had initial rhythm of ventricular fibrillation or ventricular tachycardia (unstable, rapid heart rhythm) or rhythms that were shockable by an automated external defibrillator; and 954 (4.6 percent) were discharged alive.

The incidence of EMS-treated cardiac arrest per 100,000 population ranged from 40.3 to 86.7; for ventricular fibrillation, the incidence per 100,000 population ranged from 9.3 to 19.0.

The EMS-treated cardiac arrest survival across sites ranged from 3.0 percent to 16.3 percent; ventricular fibrillation survival ranged from 7.7 percent to 39.9 percent, with significant differences across sites for incidence and survival.

“These findings have implications for pre-hospital emergency care. The 5-fold variation in survival after EMS-treated cardiac arrest and 5-fold variation in survival after ventricular fibrillation demonstrate that cardiac arrest is a treatable condition,” the authors write.

“Out-of-hospital cardiac arrest is a common and lethal event. There are significant and important regional variations in the incidence and outcome of cardiac arrest. Additional investigation is necessary to understand the causes of this variation in an effort to better understand implications for allocation of resources to prehospital emergency care clinical practice and translational cardiac arrest research to reduce the magnitude of this variation and improve cardiovascular health.”

Editorial: Surviving cardiac arrest—location, location, location

“...it is time to recognize the importance of EMS systems to the health of a community,” writes Arthur B. Sanders, M.D., and Karl B. Kern, M.D., of the University of Arizona, Tucson, in an accompanying editorial in this week’s JAMA.

“Physicians and the public should demand data on survival from cardiac arrest from every community. Publications and organizations should use these survival data when rating cities for livability and health indices, and businesses and individuals should take these public health data into account when deciding whether to relocate or expand to a new city.

“It is time to work to overcome barriers in each community, devote appropriate resources, and optimize survival of all patients so that location by city becomes a minor factor in survival of cardiac arrest.”

More Links to News About Cardiac Arrest

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  More About Cardiac Arrest

The American Heart Association urges the public to be prepared for cardiac emergencies:

   ● Know the warning signs of cardiac arrest. During cardiac arrest a victim loses consciousness, stops normal breathing and loses pulse and blood pressure.

   ● Call 9-1-1 immediately to access the emergency medical system if you see any cardiac arrest warning signs.

   ● Give cardiopulmonary resuscitation (CPR) to help keep the cardiac arrest victim alive until emergency help arrives. CPR keeps blood and oxygen flowing to the heart and brain until defibrillation can be administered.

What is cardiac arrest?

Cardiac arrest is the sudden, abrupt loss of heart function. The victim may or may not have diagnosed heart disease. It's also called sudden cardiac arrest or unexpected cardiac arrest. Sudden death (also called sudden cardiac death) occurs within minutes after symptoms appear.

What causes cardiac arrest?

The most common underlying reason for patients to die suddenly from cardiac arrest is coronary heart disease. Most cardiac arrests that lead to sudden death occur when the electrical impulses in the diseased heart become rapid (ventricular tachycardia) or chaotic (ventricular fibrillation) or both. This irregular heart rhythm (arrhythmia) causes the heart to suddenly stop beating. Some cardiac arrests are due to extreme slowing of the heart. This is called bradycardia.

Other factors besides heart disease and heart attack can cause cardiac arrest. They include respiratory arrest, electrocution, drowning, choking and trauma. Cardiac arrest can also occur without any known cause.

Can cardiac arrest be reversed?

Brain death and permanent death start to occur in just 4 to 6 minutes after someone experiences cardiac arrest. Cardiac arrest can be reversed if it's treated within a few minutes with an electric shock to the heart to restore a normal heartbeat. This process is called defibrillation. A victim's chances of survival are reduced by 7 to 10 percent with every minute that passes without CPR and defibrillation. Few attempts at resuscitation succeed after 10 minutes.

How many people survive cardiac arrest?

No statistics are available for the exact number of cardiac arrests that occur each year. It's estimated that more than 95 percent of cardiac arrest victims die before reaching the hospital. In cities where defibrillation is provided within 5 to 7 minutes, the survival rate from sudden cardiac arrest is as high as 30–45 percent.

What can be done to increase the survival rate?

Early CPR and rapid defibrillation combined with early advanced care can result in high long-term survival rates for witnessed cardiac arrest. For instance, in June 1999, automated external defibrillators (AEDs) were mounted 1 minute apart in plain view at Chicago's O'Hare and Midway airports. In the first 10 months, 14 cardiac arrests occurred, with 12 of the 14 victims in ventricular fibrillation. Nine of the 14 victims (64 percent) were revived with an AED and had no brain damage.

If bystander CPR was initiated more consistently, if AEDs were more widely available, and if every community could achieve a 20 percent cardiac arrest survival rate, an estimated 40,000 more lives could be saved each year. Death from sudden cardiac arrest is not inevitable. If more people react quickly by calling 9-1-1 and performing CPR, more lives can be saved.

>> Go to this American Heart Association presentation on Cardiac Arrest

Related AHA publications:

>> Heart and Stroke Facts

>> Heart Disease and Stroke Statistics Update

Unified national effort needed to save lives by increasing use of CPR

American Heart Association scientific statement

Jan. 15, 2008 – A unified effort by the public, educators and policymakers is needed to reduce deaths from sudden cardiac arrest by increasing the use and effectiveness of cardiopulmonary resuscitation (CPR), according to a new statement from the American Heart Association.  The statement, “Reducing barriers for implementation of bystander-initiated cardiopulmonary resuscitation,” appears online in Circulation: Journal of the American Heart Association.

“Bystander cardiopulmonary resuscitation rates are woefully inadequate, resulting in an enormous missed opportunity to save lives from cardiac arrest,” said Benjamin S. Abella, M.D., M.Phil., clinical research director for the Center for Resuscitation Science at the University of Pennsylvania in Philadelphia, and lead author of the statement. 

Studies indicate that in many communities only 15 percent to 30 percent of out-of-hospital cardiac arrest victims receive bystander CPR before emergency medical services (EMS) personnel arrive at the scene.  Considering that cardiac arrest survival falls an estimated seven percent to 10 percent for every minute without CPR, the low rate of bystander CPR has a big impact on outcomes, he explained.

Approximately 166,200 out-of-hospital sudden cardiac arrest deaths occur annually in the United States.  Sudden cardiac arrest often results from an irregular heartbeat called ventricular fibrillation (VF) which causes the heart to quiver so that it cannot generate blood flow.  Treatment of VF requires CPR to keep blood moving through the body until the patient’s heart can be shocked to terminate the VF and allow the heart’s pacemaker cells to establish a normal rhythm.  

In the last decade, automated external defibrillators (AEDs), portable defibrillation machines, have become increasingly common in public buildings such as casinos, airports and schools.  However, Abella said defibrillation is only one of the four links in the Chain of Survival, a sequence of four actions that must occur quickly to help ensure the best chances of survival.

The Chain of Survival requires: (1) early recognition of the emergency and phoning 911 for EMS, (2) early bystander CPR, (3) early delivery of a shock via a defibrillator if indicated and (4) early advanced life support and post-resuscitation care delivered by healthcare providers.

“Quick initiation of CPR, as well as providing high quality CPR, is crucial to survival,” Abella said.  “What’s needed is a two-pronged approach: first, substantially increase the number of bystanders trained in CPR who then provide CPR during an actual emergency and second, improve the quality of training and actual CPR performance through measures of its effectiveness.”

“In communities where widespread CPR training has been provided, survival rates from witnessed sudden cardiac arrest associated with VF have been reportedly as high as 49 percent to 74 percent,” Abella said.  “Unfortunately, on average, approximately six percent of out-of-hospital sudden cardiac arrest victims survive to hospital discharge in the United States.”

The statement identifies specific potential barriers to improving U.S. cardiac arrest survival rates including: fear of infectious disease, fear of litigation and fear of poor performance, all of which Abella said could be overcome with adequate education, training and public awareness.

Specific recommendations in the statement include:

   ● Local, state and federal government agencies should provide CPR education in such settings as school systems and government-funded hospital and clinic systems.

   ● Communities should create and support emergency dispatcher-assisted CPR training programs with an emphasis on recognizing the symptoms of cardiac arrest.

   ● The public should understand that when bystanders perform CPR immediately, the victim’s chance of surviving cardiac arrest can double or triple at little risk to the rescuer.

   ● The public should be made aware of Good Samaritan laws through CPR training materials and by including information with community AEDs.

   ● Community lay rescuer and EMS programs should include a process for continuous quality improvement that includes a review of resuscitation efforts, quality of CPR and CPR instructions provided to bystanders by dispatchers.  CPR instructional programs should always include an objective CPR quality assessment for certification.

   ● Research funds should be targeted toward improving methods of CPR education, skill retention and creative methods to widen the scope of current CPR training and education.

Abella said creative approaches to CPR education include initiatives such as the American Heart Association’s Family and Friends CPR Anytime™, a 22-minute, individual training program that provides an instructional video and an inflatable manikin, and other approaches such as Internet-based instruction.  Another idea is to provide hospital-based training for family members of patients at risk for cardiac arrest.

The statement also recommends directing research dollars to learn more about ways to increase the use of bystander CPR.

“By broadening training and encouraging the public to perform CPR, we believe we can save thousands of additional lives each year in the United States,” Abella said.

Co-authors are:   Tom P. Aufderheide, M.D.; Brian Eigel, Ph.D.; Robert W. Hickey, M.D.; W.T. Longstreth, Jr., M.D.; Vinay Nadkarni, M.D.; Graham Nichol, M.D.; Michael R. Sayre, M.D.; Claire E. Sommargren, R.N., Ph.D.; and Mary Fran Hazinski, R.N., M.S.N.