PHILADELPHIA -- Publicly-accessible automated external defibrillators (AEDs) can seem near-miraculous in their ability to pull sudden cardiac arrest victims back from sure death. Not surprisingly, stories of their successes have a strong emotional appeal in a country where more than 900 people die of cardiac arrest every day. But actually measuring and analyzing the national scope and impact of this "bystander"
Photo: Hoag Levins
The nearly-miraculous medical capabilities of AEDs are well established but scientific data about their placement, use and outcomes is lacking.
AED emergency response model remains an elusive goal for policy makers and the nation's health care research community.
Hardly larger than laptop computers, AEDs are smaller versions of the manually-operated devices long used in hospitals to shock a suddenly-stopped human heart back into a normal rhythm. AEDs are so fully automated that aside from flipping the power switch and placing their adhesive "paddles" on a person's bare chest, the user has only to press one or two buttons to complete the process. One 2006 Journal of the American Medical Association article hailed them for being so laymen-friendly "they may be used appropriately by individuals with as little as a sixth-grade education."
There are now an estimated 1 million of these devices in place across the U.S. and studies over the last two decades clearly show that when properly used by a bystander within minutes of a sudden cardiac arrest an AED can dramatically increase survival probability.
Lack of scientific data But other facts about the deployment, use and efficiency of publicly-accessible AEDs are less well defined, even as governments, corporations and individuals purchase and install an estimated $500 million worth of additional machines each year. There is, for instance, a lack of central registries at the city, state and national level capable of routinely gathering data about AEDs' exact locations or battery power levels or overall operational status. Also largely unknown are the criteria used to place many of them in their current locations, or how many times they are used by members of the public, or what the outcomes of those emergency response events are, or how the bystander AED model's overall national benefits compare to its overall costs.
Dr. Michael Sayre, Vice Chairman of the American Heart Association's Emergency Cardiovascular Care Committee, says the lack of fundamental scientific data on AED resusciation
Dr. Michael Sayre, Vice Chairman of the American Heart Association's Emergency Cardiovascular Care Committee finds the lack of AED data frustrating.
trends reminds him of the famed adage from the eminent 19th-century scientist Sir William Thompson Kelvin that "If you can't measure it, you can't improve it."
'Missed opportunities' "There absolutely are a lot of missed opportunities because of our inability to really measure what's going on with AEDs," said Dr. Sayre, who is also an Associate Professor of Emergency Medicine at Ohio State University Medical Center. "This sort of data gathering has proven to be more difficult than many people initially imagined it would be."
Dr. Graham Nichol, medical director of the clinical trial centers of both the University of Washington and the national Resuscitation Outcomes Consortium, agrees. "The biggest challenge to expanding the public's use of AEDs is lack of knowledge about the location of the devices," he said. "There is no systematic data gathering about patterns of AED distribution, use or outcome. Nor is there systematic data gathering about out-of-hospital cardiac care process and outcome. A few years ago, some of us recommended designating cardiac arrest as a public health condition to facilitate this reporting but there has been little progress since then."
Bystander reticence Despite the machines' proven life-saving potential, actual use of AEDs by members of the general public has remained relatively low. Multiple studies over the last decade indicate that sudden cardiac arrests in public spaces are often observed by large numbers of bystanders, almost all of whom do nothing beyond calling 911.
The widespread installation of the battery-powered, knapsack-sized devices in public locations ramped up dramatically after passage of the 2000 Cardiac Arrest Survival Act mandating their placement in federal buildings. At the time, Congressional testimony by the American Heart Association and announcements by President Bill Clinton predicted that the use of such bystander AEDs would save 20,000 more lives a year.
Ten years later, in 2010, extrapolating from its studies in eight U.S. and two Canadian cities, the Resuscitation Outcomes Consortium,
Sudden Cardiac Arrest Association President Lisa Levine says U.S. culture has not yet embraced the AED.
a multi-center collaboration of U.S. and Canadian cardiac arrest investigators, estimated that bystander AEDs save a total of about 474 lives annually across both countries.
Tiny percentage That same year, the Cardiac Arrest Registry to Enhance Survival (CARES), set up in 2004 by the Centers for Disease Control and Emory University's School of Medicine, finalized a report of its first 63 months of monitoring out-of-hospital cardiac arrests (OHCA) in 36 communities in 20 states. A bystander AED was used in 1,172 of 31,689 incidents and a total of 275 of those victims survived.
Dr. Vincent Mosesso, Jr., Medical Director of both the University of Pittsburgh Medical Center's Prehospital Care Services and the national Sudden Cardiac Arrest Association (SCAA), said that nationally only two percent of sudden cardiac arrest victims get treated with a bystander AED and "there's a huge potential to save more." A patient-advocacy nonprofit headquartered in Washington, D.C. with 52 chapters across the country, the SCAA's 6,000 members are mostly cardiac arrest survivors, health care professionals and emergency responders.
Little impact Overall, available evidence suggests that fifteen years of equipping American buildings with hundreds of thousands of bystander AED units has had little impact on national out-of-hospital cardiac arrest (OHCA) survival statistics. Circulation, the American Heart Association Journal, published a 2010 report on a systematic review of 79 studies of U.S. resuscitation trends. It concluded that "Survival from OHCA has not significantly improved in almost 3 decades, despite enormous efforts in research spending and the development of novel drugs and devices."
"What's both sad and frustrating is that the AED has not become ingrained in our culture yet," said SCAA President Lisa Levine. "We need to not only incorporate these devices into our buildings but into our community consciousness as well -- and that hasn't happened." To change that, the SCAA is lobbying to have AED orientation made a mandatory in America's high schools.
"If we did that," Levine said, "in just four years we'd have hundreds of thousands of AED-trained individuals out in their communities. But that's been an uphill battle because it's one thing to mandate training and quite another to fund it."
Beyond the lack of basic knowledge that impedes wider bystander-AED use is the even larger problem of
Photo: Hoag Levins
Emergency physician Raina Merchant is concerned about the public's inability to quickly find out where AEDs are located.
knowing where to find one when you need it. In a 2010 article about AEDs in Current Opinion in Critical Care, University of Iowa Children's Hospital pediatrician Dr. Diane L. Atkins wrote "the author is aware of three instances in Iowa, Georgia and Washington where a student died despite the onsite availability of an AED. In each case, the AED was not used because its presence was unknown to those around the victim."
AED locations not known On the other side of the country, this same issue has energized Dr. Raina Merchant, Assistant Professor of Emergency Medicine at the University of Pennsylvania's Perelman School of Medicine in Philadelphia. "If you're trying to increase the use of AEDs across any geographic area, the first step is to make sure that members of the general public, or the 911 centers they most often call, have some quick, easy way to find out exactly where local AEDs are, but that's exactly what you don't find in city after city," she said.
During the last decade, most states passed laws authorizing the use of AEDs; some statutes call for central registries but few jurisdictions have established such databases. And even those that have tried have encountered unexpected problems. For instance, Washington State is generally regarded as having the country's best-organized public AED program along with a law requiring registration of all public machines and locations. In King County, comprising Seattle and its suburbs, the AED registry is part of the computer system of the EMS dispatch centers. In a three-year study of those centers' daily operations from 2007 to 2009, researchers analyzed the role that AEDs played in local response to all the county's out-of-hospital cardiac arrests. One surprising finding was that more than half of the public AED units bystanders actually used to treat OHCA victims were not in the county's highly-regarded EMS database or shown on its AED map.
Difficult challenge "I think the example of King County is instructive," said Dr. Merchant. "Even in that Mecca for resuscitation science, they didn't have 50% of the devices in their database. It illustrates how difficult a challenge this is for any city or county."
In Philadelphia, Dr. Merchant is spearheading an innovative effort to create the country's first interactive city directory and map of crowd-sourced AED locations. A research fellow at both the Leonard Davis Institute of Health Economics and Penn Medicine's Center for Resuscitation Science, she has raised funds from organizations like the Robert Wood Johnson Foundation's Health and Society Scholar's program, and organized the creation of MyHeartMap.org. Over the last several months, the social media initiative recruited more than 300 smartphone-wielding AED documenters with a contest offering a cash prize to the person who found the most public AED locations. In early May when the contest ended, more than 1,500 AEDs had been located. Each of the two winners found and photographed more than 400 devices, and each won a $9,000 prize. The information generated by the contest has been entered into a database and will soon be the core of a GPS-connected interactive smart phone app that can be used to quickly locate the nearest AED anywhere in Philadelphia.
Lack of knowledge and inclination In recent years, other researchers have looked at the general public's attitudes toward bystander AEDs and reported a significant lack of knowledge as well as inclination. Researchers in U.S., European and Japanese cities found that a high percentage of "bystander" AED responders in public places were actually off-duty professionals trained in emergency response procedures, including healthcare workers, police officers, firemen and EMS technicians.
A shopping mall study by investigators from Brown University and the University of Pittsburgh found that 57% of the public were not willing to use an AED for fear of operating it incorrectly and further harming the victim. Thirty eight percent were worried that using an AED on a dying person could potentially ensnare them in personal legal liabilities. The actual facts are that in most states, Good Samaritan laws specifically absolve public AED responders from any legal liability related to their resuscitation attempts and medical authorities say AEDs aren't dangerous to use.
"There's almost no chance of doing any harm to yourself or to the patient with an AED," said
Three-Year Project to Create a Registry of Locations
University of Pennsylvania emergency physician Zachary Meisel. "These units are fully automated; they read the downed person's cardiac rhythm and won't shock if the patient doesn't need it. So, when in doubt, use the AED along with manual chest compressions -- because that can prevent not only death but long term neurological injury."
Nevertheless, concerns about using AEDs appear to share a certain international consistency. When a five-member team from Amsterdam's VU University Medical Center surveyed more than 1,000 travelers from 38 nations passing through that city's central railway station, they found that 47% were not willing to use an AED and 53% did not know what an AED was when shown one. Forty nine percent believed only medical personnel were authorized to access the station's wall-mounted AEDs.
'Not yet sufficiently prepared' The researchers' 2011 paper in the Annals of Emergency Medicine concluded that "Only a minority of individuals demonstrate sufficient knowledge and willingness to operate an AED, suggesting that the public is not yet sufficiently prepared for the role... Wide-scale public information campaigns are an important next step to exploit the lifesaving potential of public access defibrillation."
In Philadelphia, Dr. Merchant's social media AED mapping project is designed to be both an information gathering effort as well as a promotional campaign employing the culture's most popular digital communications technology to directly engage large numbers of local residents with the issue of sudden cardiac arrest and AED function. It has spawned waves of stories about AEDs in the local and national print, online and TV media.
"We used the fun of the chase and the gadget-enthusiasm of gamers and techies and geocachers to make this thing fly as an educational exercise," said Dr. Merchant. "It's collecting data we need and improving the participants' awareness of these devices and their life-saving importance."
The same kind of central AED database Merchant is working to establish in Philadelphia can also be useful in managing other aspects
Photo: Hoag Levins
Once installed, AEDs remain in place for years and require routine maintenance and functionality testing. Their batteries slowly deplete and their chest pads also "age out" and can become dysfunctional.
of citywide defibrillator programs, like device maintenance and operability. Because so few jurisdictional authorities have accurate central AED registries, it's impossible to generate the address lists that would enable local officials or journalists to systematically visit a region's AED sites to check the maintenance and battery-life date on the front of each machine; or ascertain if there is a maintenance program in effect for a given group of AEDs that have hung on the same walls for years.
The same lack of ownership and location data can also inhibit the recall or repair of AED models that have been found to be defective. AEDs are curious in that they are a Class III medical device sold as consumer electronics products through mass-market outlets like Walmart and Amazon.com. Class III devices are the most strictly regulated by FDA and are typically only available via physicians and hospitals; AEDs are covered by the same rules that apply to defibrillators implanted in the body. But the two kinds of devices are subject to very different record-keeping protocols.
FDA advisories For instance, surgically-implanted defibrillators must be documented in a central national registry run by the American College of Cardiology. When the FDA issues advisories about potential mechanical problems or dangers in various implantable models, it's relatively easy to know where the defective units are, as well as to communicate with the hospital and surgeons that put them in. But what happens when the FDA must issue advisories about potentially defective AEDs whose malfunction could directly result in a life not being saved?
In 2006 Dr. Jignesh Shah of Beth Isreal Deconess Medical Center and Harvard Medical School and Dr. William Maisel, now chief scientist of the FDA's Center for Devices and Radiological Health, completed a study of AED advisories and published their findings in the Journal of the American Medical Association. They found 52 FDA advisories affecting 385,922 AED units and noted that "current advisory notification schemes arguably do not adequately inform the public" because there were so few records of where the AEDs were located or exactly who owned or oversaw them.
'Impossible to know' The authors went on to conclude "the inability to track devices and end users makes it impossible to know how many AED units were actually fixed or taken out of service during the study period because of these advisories... efforts should be directed at developing a reliable system to locate and repair potentially defective (AEDs) in a timely fashion."
That often-broken connection between AEDs installed in unknown locations and FDA safety advisories is only one part of the larger challenge of maintaining such devices in a fully-operation state over long periods of time.
What is believed to be the first academic study to assess the routine maintenance and long-term functionality of a typical cluster of public AEDs was published in the journal, Resuscitation, in 2009. University of Iowa investigators visited business, school and government building AED locations throughout Johnson County, Iowa. They wrote, "AEDS were frequently inaccessible and were noted to have depleted batteries and/or expired AED pads... Consistent maintenance protocols need to be implemented to insure that successful defibrillation is possible when a sudden cardiac arrest occurs."
AEDs malfunctioned, patients died A few months ago a team of researchers led by Dr. Lawrence Deluca of the University of Arizona's Emergency Medicine Research Center published the result of their study of FDA AED adverse event reports in the Annals of Emergency Medicine. They analyzed 1,150 instances in which an AED failed to operate properly and the sudden cardiac arrest victim being treated died. The authors wrote that "data on device maintenance ...were frequently absent" and that "underreporting, inadequate tools for analysis, and lack of structured data collection" thwarted efforts to determine the cause of many AED failures in fatal adverse events.
In its latest External Defibrillator Improvement Initiative Paper, the FDA emphasizes the importance of enhancing the safety and effectiveness of AEDs as well as the manual defibrillators used by emergency response teams. It notes, "Over the past five years we have seen persistent safety problems with all types of external defibrillators, across all manufacturers of these devices. From Jan. 1, 2005 to July 10, 2010, there were 68 recalls, exhibiting an increase from nine in 2005 to 17 in 2009, the last complete year for which data are available. During this period, the FDA received more than 28,000 medical device reports (MDRs), which also exhibited an increase from 4,210 in 2005 to 7,807 in 2009."