Defibrillators Malfunction at Shockingly High Rates

By Sarah Zhang | February 28, 2012 3:34 pm

spacing is important
Diagram for AED electrode placement.

Touted as life-saving devices, some 1.5 million automated external defibrillators (AEDs) are around the US. AEDs are designed to be used by anyone, regardless of training, to restore normal heartbeats after sudden cardiac arrest. And in this life-or-death situation, a surprisingly number of the devices fail.

Between 2005 and 2009, there were 28,000 reports of AED malfunction in the US, representing 1 out of 50 devices in the country. Mark Harris at IEEE Spectrum investigates the cause of these failures. Surprisingly basic engineering errors were responsible for some of the malfunctions, such as parts that are just too imprecise for a matter of life or death:

One AED, the brand name of which the FDA would not disclose, was found to occasionally misdiagnose the heart’s electrical rhythm. It delivered some shocks that weren’t needed and failed to deliver others that were. The culprit was a resistor that could vary in resistance by up to 10 percent of its stated value. “When our engineer looked at this design, it was an instant ‘uh‑oh,’ ” says [Al Taylor of the FDA].

How could regulations on medical devices be so lax? Harris explains a loophole in the FDA regulation system:

If you count AEDs as Class III devices—those intended to support and sustain life—then manufacturers must produce extensive efficacy, safety, and reliability data, usually provided by large-scale clinical trials. This process can cost upward of US $800 000 and take two years.

Manufacturers can, however, get around those requirements, thanks to what’s called the 510(k) process, which effectively removes AEDs from Class III. The process requires merely that a new AED be “substantially equivalent” to any AED on the market. The 510(k) system was originally intended as a temporary measure to grandfather in devices already on the market in 1976. More than 30 years later, the process is still being used to clear AEDs.

While this system sounds broken, strict regulations always have to be weighed against access. If standards were so high that AED devices have trouble getting approved in the first place, that’s still not much help to someone in cardiac arrest. “You can always find engineering problems, but patients in cardiac arrest are predominantly going to die,” physician Gust Bardy told IEEE Spectrum. “The more restrictions one puts on AEDs and the more demands for AED perfection, the fewer lives will actually be saved.”

In fact, lack of access to AEDs is probably responsible for more deaths than faulty ones: AEDs were used in only 4% of sudden cardiac arrest cases out in public places. Mark Hardy’s feature at IEEE Spectrum explores how better policy on the regulation and deployment of AEDs can save more lives.

Image via Wikimedia Commons / PhilippN

CATEGORIZED UNDER: Health & Medicine, Technology
  • Chris

    When in doubt, just do like Mr. Bean does

  • Al Cibiades

    So misdiagnosis due to imprecise R values is OK because having 10 “typical” AEDs is better than having 1 “precise” AED?
    I don’t get the point of this story.

  • Redshift

    The point is, these devices need to be safer BUT you can’t make the regulations so strict that no company is willing to produce them

  • Kate T.

    I find this article simultaneously interesting and disturbing. It begins by reporting on a real issue that may very well be costing human lives and at the very least is wasting money and time in the health care system–then goes on to downplay and excuse it. It’s like giving a kid a broken toy and saying, “Well, at least you got a toy!” We’re supposedly a “developed nation.” Can we do no better than that?

    While it’s probably safe to say lack of access is (currently) the more likely cause of death when it comes to this situation, if there *is* access to an AED, I think it’s *also* safe to say you’d rather have one used on you that bloody well worked and wasn’t prone to malfunctioning due to “basic engineering errors.” I’d like to see data of American health care providers’ experiences of using AEDs compared to some other nations’ (e.g., Canada, Australia, Norway, etc.), where, I’m guessing, there would be more regulation on this sort of device.

  • XT-3000 Larynx Extractor

    Pun intended?

  • Paul


    I see what you did there.

  • jasvll

    After reading the argument put forward in the article, it’s clear to me that the solution to the problem of limited access to AEDs is updating the regulations to allow manufacturers to market those novelty handshake buzzers as AEDs. They’re much cheaper, making it possible for every home, possibly every individual, to have immediate access to an AED.

  • Squirtly

    No no no! Defibrillators are NOT used to shock a beatless heart back to life. They STOP hearts that have entered irregular rhythms (called fibrillations, hence the name DEfibrillator) in the hopes that they’ll start back up in sinus rhythm. This may be overly pedantic and irrelevant to the article, but it’s a very important distinction that nobody seems to get right. Zapping a stopped heart will only keep it silent.

  • Brian Too

    This problem may well be under-recognized for another reason. Victims in cardiac arrest/arrhythmia are in deep and obvious trouble. If the AED fails them it would be, ah, not unlikely that bystanders would assume they were beyond help.

  • plomeley

    Bad news, regs in Australia are no stricter and with the march of globalised regs are essentially the same. Note also we rely on FDA database for failure rate data – local info I
    is not publicly available…

  • foci eredmények

    So there aren’t any other alternatives for AED? safer ones? Is so pathetic that even they know is a wrong procedure they still use it

  • Rimai

    I´ve personally seen an automated defibrilator malfunctionig in resuscitation situation.
    Luckily we took the decission to defibrillate manually after some five to seven minutes from the start of the resuscitation. The patient survived, but if we had trusted the device the outcome would have been different. The reason behind the malfunction was that the device couldn´t detect the ventricular fibrillation due to bad connection of a cable. In my opinion this kind of malfunction could be avoided with a better design of the defibrillator. Poorly designed defibrillators shouldn´t be allowed on the defibillating busines…

  • Sarah Zhang

    @Squirtly, you’re right the wording was a little sloppy. Fixed to clarify.

  • Wil

    I have been designing and making medical devices (in the U.S.) for 28 years. Over the past few years, the FDA has been hammering all defibrillator manufactuers in the U.S., large or small. There have been good reasons for the attention, but those reasons do not include the fact that the products were released via a 510(k), instead of a PMA.

    Most medical device manufacturers put a great deal of time, money, and effort into a brand new device, until it gets a 510(k) or PMA clearance and goes onto the market. Then the engineers and the big budgets are diverted to the next brand new device, and the just- launched device stays pretty much the same, and ignored, for the next 10 to 30 years. This long product life span means that product redesigns (which would normally catch any design flaws) and new technologies do not find their way into the older products very often.

    Over the past 40 years the FDA has gradually, and substantially, raised the bar. This is also true of the ISO international technical standards. Medical devices of the 1970’s that were considered brilliant, safe and were quickly cleared by the FDA, would be laughed out of the room today. This is also true of the processes used to design, validate, and manufacture the devices.

    The main reason that a PMA is required for Class III devices isn’t that it is a superior process for catching design flaws than a 510(k) is. The first reason is that if a device is truly a new technology, then its safety and efficacy has to be proven in the human body. The second reason is that if a device is life saving, life preserving, or life extending, then it needs to pass a much more challenging testing regimen than if it wasn’t.

    The defibrillators mentioned in the above article would have failed any testing what-so-ever, let alone a challenging testing regimen.

  • Drew

    I guess having some AED’s around that work is better than having no AED’s. It’s like some CPR is better than no CPR.

  • Wendy Clarke

    The Lifeline View defibrillator shows you
    what to do in an emergency in full colour, high definition video, check it out


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