Anicka Slachta | September 26, 2017 | Heart Failure

Automated external defibrillators might be increasingly available and encouraged for public use in the case of out-of-hospital cardiac arrests (OHCA), but a study recently published in the European Heart Journal found they aren’t being used nearly as much as they should be.

Public access defibrillation (PAD) is only used in 0.15 to 4.3 percent of OHCA, lead author Christopher M. Smith and colleagues wrote in the study, though automated external defibrillators (AEDs) are safe and intended for use by any bystander witnessing a medical emergency. Smith and co-authors performed an extensive search of MEDLINE and EMBASE databases for articles about PAD, eventually narrowing the field to 68 studies which they used to better understand why the public is shying away from AED use, and what barriers and facilitators are involved in the PAD process.

“A clinical intervention of great efficacy has had only a limited impact on OHCA at a population level,” Smith and co-authors wrote. “An understanding of the reasons why PAD is used so infrequently is vital to increasing its effectiveness and improving survival.”

Most of the articles were in the form of surveys or interviews, or otherwise observational studies, the researchers wrote. Smith and colleagues identified 11 “core themes” in their findings, all of which contributed to PAD use—or lack of use—across the world: knowledge and awareness, willingness to use, acquisition and maintenance, availability and accessibility, training issues, registration and regulation, medicolegal issues, dispatch-assisted AED use, AED locator systems, demographic factors and human factors.

Awareness of AED use fell into a large range on the population level—according to Smith’s research, between 15 and 89 percent of populations studied knew what AEDs were and how to use them. As few as 5 percent but as many as 22 percent of individuals were able to find their nearest public-access AED.

When asked about willingness to use the device, most members of the public were wary. As many as 85 percent, 84 percent and 88 percent of people surveyed said, respectively, they were worried about not knowing how the device worked, not feeling comfortable using it or feared causing harm to the patient. A small percentage were also worried about legal liability. Still, 88 percent of surveyed populations said they’d be willing to study CPR and AED use so they would feel more comfortable using those techniques in the future.

Effective facilitators of PAD were increased knowledge, awareness and training, trust that the AED was well-made and would work, and a willingness to learn on the public’s part. Barriers were numerous, including inaccessibility of the AEDs, poor maintenance, discomfort in using the device and lack of training.

Smith and co-authors noted that while investing in increasing public access to AEDs is “commendable,” people could make better use of what’s already available to them. One barrier to AED use, though, is that many of the devices aren’t available for 24-hour emergencies.

“Many OHCAs occur outside of ‘normal business hours,’ and many public-location AEDs are not available at these times,” Smith and colleagues wrote. “Targeted location of AEDs will be most effective if combined with efforts to improve actual availability.”

Increased survival rates have been seen in victims who received PAD before emergency medical services arrive, the authors wrote, compared with solely first-responder AED use. Despite this statistic, many people don’t think of themselves as equipped to administer AED, even though the devices are designed for easy, fast use by anyone—a fact the study’s authors think is important to broadcast. Emergency responders can also help guide someone through AED use over the phone, they wrote.

“This review highlights a number of key barriers to PAD,” Smith and co-authors stated in the paper. “Few people know what an AED is, where to find one, or how and by whom one can be used. There is variation in the proportion of people willing to use an AED reported in studies, but lack of confidence and fear of harm are common themes. Many organisations do not feel that they should obtain an AED or feel unable to do so.”

The authors also noted their survey-based evidence is limited, and, due to its nature, low-quality. The review points out highs and lows of PAD, but doesn’t advocate for any particular improvements or policy changes in public AED usage.

“Public access defibrillation represents an efficacious means of improving OHCA survival, but its effect at a population level is greatly hampered by low usage rates,” they wrote. “An increase in PAD will require robust methods to identify barriers to public-access AED use and theoretically informed interventions developed using validated frameworks.”

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