Proper placement of defibrillators key to effective use

Jul 28, 2009

The appropriate placement of automated external defibrillators (AEDs) is critical to optimize their use in public places, according to two studies published in Circulation: Journal of the American Heart Association.

Sudden is the sudden, abrupt loss of . Without immediate bystander cardiopulmonary resuscitation (CPR), brain death and permanent death start to occur in just four to six minutes after someone experiences cardiac arrest. Cardiac arrest can be reversed by immediate bystander CPR and treatment within a few minutes with an to allow the heart to restore a normal heartbeat. More than 92 percent of out-of-hospital cardiac arrest victims don't survive to hospital discharge. In cities where bystander CPR and defibrillation is provided within 5 to 7 minutes, the survival rate from out-of-hospital sudden cardiac arrest is as high as 30 percent to 45 percent, according to the American Heart Association.

In one study, researchers found that school-based AED programs have a high rate of survival for students and others on school grounds.

Researchers found that 83 percent of 1,710 U.S. high schools with AED programs that they studied had an established plan for sudden cardiac arrest. However, only 40 percent practiced and reviewed their plans at least annually with potential school responders.

Of 36 cases of sudden cardiac arrests at the 1,710 schools:

  • 94 percent received bystander CPR,
  • 83 percent received an AED shock and
  • 64 percent survived to including 9 of 14 student athletes and 14 of 22 non students.
Three factors — prompt recognition of sudden cardiac arrest, the presence of a trained rescuer to initiate CPR and access to early defibrillation through on-site AEDs — are critical to improving survival from sudden cardiac arrest in schools, said Jonathan A. Drezner, M.D., lead author of the study and associate professor and team physician in the Department of Family Medicine at the University of Washington-Seattle.

"It is not just about the AEDs — schools must have a comprehensive emergency response plan for sudden cardiac arrest that includes training anticipated responders in CPR and AED use, access to an AED, and practice and review of the response plan," Drezner said.

"It is crucial to recognize that AEDs permit early defibrillation not only in young athletes but also in other individuals who may experience an unexpected sudden cardiac arrest. We found that more than half of sudden cardiac arrest events reported in schools occur in adults working at the school or attending a school event. Schools are a strategic location for AED programs to serve large concentrations of people at risk for sudden cardiac arrest."

In a Danish study, researchers examined strategic placement of AEDs in public urban locations. A significant amount of interest and money is focused on AED deployment and public access defibrillation programs worldwide, but knowledge about where and how widespread AED deployment in the community should be is lacking, said Fredrik Folke, M.D., lead author of the study and a cardiology research fellow at Gentofte University Hospital, Hellerup, in Denmark.

To evaluate whether public AEDs were located where the majority of cardiac arrests occurred, Folke and colleagues digitally marked the exact locations of all arrests on a map and then analyzed the locations of 104 AEDs placed in municipal institutions in Copenhagen, Denmark, from 1994 through 2005. About 25 percent of out-of-hospital cardiac arrests occurred in public places.

According to the cardiac arrest analysis, carefully choosing AED coverage in 10 percent of the city area would provide coverage for about 67 percent of all cardiac arrests occurring in public. The highest rates of cardiac arrest in cities were in high-density public areas such as major train stations, large shopping centers, central bus terminals and sports centers.

"Our findings suggest that public access defibrillation programs should cover the greatest possible number of arrests in public, which is consistent with the recommendations from the American Heart Association," Folke said. "But if AED deployment in the community is driven by local or political initiatives and not on strategic AED placement, there is a high risk of AEDs being placed primarily in low-incidence areas of cardiac arrest and hence low likelihood of the AEDs ever being used."

Placing AEDs in about 10 percent of the city area cost an estimated $41,000 per extra year of a survivor's life — deemed "acceptable" by the researchers. However, unguided AED placement trying to cover the entire city had an estimated cost of $108,700 per extra life year.

In an accompanying editorial, Dianne L. Atkins, M.D., a pediatric cardiologist at the University of Iowa, wrote that the two "informative" studies demonstrate that the mere presence of an AED in the general area of an arrest does not guarantee success. Successful AED programs require immediate bystander CPR and non-equipment components in addition to AED-availability, she said.

"The need for ongoing CPR training, fully-developed and executed emergency plans and links to EMS are vital to the immediate and long-term outcomes of shock delivery," Atkins wrote.

Source: American Heart Association (news : web)

Explore further: Experts call for higher exam pass marks to close performance gap between international and UK medical graduates

add to favorites email to friend print save as pdf

Related Stories

In-home AEDs don't improve sudden cardiac arrest survival

Apr 01, 2008

David Callans, MD, a professor of cardiovascular medicine at the University of Pennsylvania School of Medicine, will be available to comment on the New England Journal of Medicine study on the use of automated external defibrillators ...

Study prompts new mandate for N.C. high schools

Mar 09, 2009

A new study at Wake Forest University School of Medicine reveals that many N.C. high schools are not adequately prepared to handle the immediate medical needs of a student or employee who suffers a sudden cardiac arrest on ...

Recommended for you

Obese British man in court fight for surgery

Jul 11, 2011

A British man weighing 22 stone (139 kilograms, 306 pounds) launched a court appeal Monday against a decision to refuse him state-funded obesity surgery because he is not fat enough.

2008 crisis spurred rise in suicides in Europe

Jul 08, 2011

The financial crisis that began to hit Europe in mid-2008 reversed a steady, years-long fall in suicides among people of working age, according to a letter published on Friday by The Lancet.

New food labels dished up to keep Europe healthy

Jul 06, 2011

A groundbreaking deal on compulsory new food labels Wednesday is set to give Europeans clear information on the nutritional and energy content of products, as well as country of origin.

Overweight men have poorer sperm count

Jul 04, 2011

Overweight or obese men, like their female counterparts, have a lower chance of becoming a parent, according to a comparison of sperm quality presented at a European fertility meeting Monday.

User comments : 0

More news stories

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.