A Shocking Truth

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A Shocking Truth

1212 SoftwareBugs cause errormessages or malfunctions.43596781011Power-up self-test13If tests miss componentdefects, the device may fail.6 Voltagemonitoring circuitIf this draws power from thesource it monitors, a falsealert can cause a shutdown.Circuit boards7Faulty circuit boards arethe main cause of repairs onmalfunctioning AEDs.8 ResistorsThe wrong resistor canlead to misdiagnosis of theECG waveform.9 BatteriesProblems with powermanagement, recharging,or accidental discharge canmake AEDs cancel shocks.10 ElectrodesThese can dry out if notmaintained and regularlyreplaced.11 PaddlesSkin burns may occur atthe electrode sites,parti cul arly during repeateddefibrillation attempts.14 Locationand displayMany units are inaccessibleor marked “For use bytrained personnel only.”james provostfunctional, and ready to operate at a moment’snotice, often by people who have never seen a defibrillatoroutside of a TV hospital drama.“It was a really daunting technical challenge,”says Carl Morgan, who developed some of the firstpublic AEDs at Heartstream (now part of Philips).“We helped pioneer the concept of self-test, wherethe device wakes up every day and performsextremely comprehensive tests on itself. Theseare supplemented by other tests done weekly andmonthly to conserve the battery.”In modern AEDs, he adds, twice as much softwarecode is dedicated to self-testing as to signalprocessing (for analyzing heart rhythms), and thebulk of the device’s battery power is also reservedfor tests. Even so, things occasionally go wrong.Last year, officials at the U.S. Food and DrugAdministration (FDA) noticed a disturbing trend.Between 2005 and 2009, the annual number of problems reportedwith AEDs increased by 85 percent. Medical-device reports areissued by manufacturers whenever they think one of their unitsmay have malfunctioned, contributing to a death or serious injury.In that five-year period there were more than 28 000 such reports—one malfunction for every 50 devices in the country. More than 750of the reports followed a death. Problems included the AED displayingerror messages, being unable to power up, and failing to delivershocks. In the same period, up to 70 kinds of AEDs were recalled,including models from every AED manufacturer in the world. Ofthose recalls, 17 fell into the most serious category, in which therewas a reasonable probability that the problem would have led to seriousinjury or death.“This opened our eyes,” says Mitchell Shein, who oversees the regulationof pacemakers, defibrillation devices, and the electrical leadsattached to both for the FDA. “Was the approval process providingus with adequate control so that devices making it to market were safeand effective? We needed to make an assessment.”spectrum.ieee.orgMarch 2012 • IEEE Spectrum • NA 33


The FDA discovered that manufacturershad evaluated barely a third of themalfunctions and had identified the problemin only a third of those cases. Some90 percent of the failures were thus unexplained.Worse, because the manufacturershad declined to reveal their salesvolume to the FDA, the agency couldn’tnail down the rate of malfunction or tellwhether it had risen over time.“I was stunned to hear this,” saysE. Magnus Ohman, a physician on theFDA’s oversight panel for AEDs. “We’rein the era of transparency. If I go to a restaurant,I get the hygiene rating.” Anotherphysician on the panel, Frank LoGerfo,complains, “If these devices can selfreportafter an incident, it’s almost inexplicablethat we don’t have very detaileddata for each device where it failed.”Eventually, the agency set its own engineersto work on the job. “We found somepretty egregious design errors,” says AlTaylor of the FDA’s Office of Science andEngineering Laboratories. “There weremany situations where deficient productdesign and—let’s put it bluntly—poorengineering were a cause or a contributoryfactor to an adverse event.”One AED, the brand name of whichthe FDA would not disclose, was foundto occasionally misdiagnose the heart’selectrical rhythm. It delivered someshocks that weren’t needed and failedto deliver others that were. The culpritwas a resistor that could vary in resistance by up to 10 percent ofits stated value. “When our engineer looked at this design, it was aninstant ‘uh‐oh,’ ” says Taylor. “We would have to do analysis to decide ifit needed a 1 percent or a 0.1 percent resistor, but this was clearly off thescale.” The reason? Only at that higher tolerance can the noise- cancelingcircuitry isolate the cardiac signal from environmental sources of radiation,such as the oscillating electric fields of fluorescent tubes.In another device, a voltage-monitoring circuit drew power from thevery source that it was checking. Because of this, a momentary dropphy. William Maisel, deputy director for science atthe FDA, explains: “Fix on fail means identifying andtrending problems on a case-by-case basis, repairingindividual devices rather than communicating theproblem to all users. In one example, a firm trackedhundreds of complaints tied to a known defect. Theyserviced each device when it failed but did not systemicallynotify other users so that their devicescould pro actively be evaluated and repaired.”in voltage would cause a false signal to shut down the AED, and thedevice would be unable to deliver a shock. Still another recalled AED—made by MRL, of Buffalo Grove, Ill.—would work perfectly until somebodydropped it. The impact could cause a circuit board connector toperforate an insulation shield, creating a short circuit and generatingRF interference that would prevent analysis of the patient’s arrhythmia.Again, the unit would not deliver a shock.The companies put some of the blame on a manufacturing environmentthey say has become increasingly globalized in the past15 years. “Most of the risk today is in the supplied material, the commercialoff-the-shelf components; these are the components that go inyour iPhones and your laptops, and we don’t control their specification,”says Brian Webster, president of Physio-Control, a division ofMedtronic. “We’re prisoners of that supply chain.”Beyond failures in design and purchasing control, the FDA foundHow did the AED industry get into this state? Ithas to do with a quirk in the law regulating medicaldevices. If you count AEDs as Class III devices—those intended to support and sustain life—thenmanufacturers must produce extensive efficacy,safety, and reliability data, usually provided bylarge-scale clinical trials. This process can costupward of US $800 000 and take two years.Manufacturers can, however, get around thoserequirements, 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 “substantiallythat many AED manufacturers were practicing a “fix on fail” philoso- equivalent” to any Continued on page 57Photographer: dan saelinger; Prop Stylist: ARiana Salvato34 NA • iEEE Spectrum • March 2012 spectrum.ieee.org


A Shocking TruthContinued from page 34AED on the market. The 510(k) systemwas originally intended as a temporarymeasure to grandfather in devices alreadyon the market in 1976. More than 30 yearslater, the process is still being used to clearAEDs, as well as 25 other high-risk products,including implantable pacemakers,ventricular bypass devices, and systemsfor electroconvulsive therapy. Meanwhile,external defibrillators have graduatedfrom manual operation that requires somedegree of skill to complete automation.They have also been upgraded to administera biphasic shock, use rechargeable batteries,and incorporate LCD screens, CPRpacing systems, voice prompts, and selftestingcircuits. These features add to thethings that can go wrong—and as they wereintroduced, they were grandfathered in.In a recent report, the Institute ofMedicine of the National Academies notedthat “Prior 510(k) clearances are legallybinding on the FDA when making clearancedecisions. Thus, any unsafe or ineffectivedevices are embedded in the system.”Dr. Michael Carome, a physician with theconsumer advocacy group Public Citizen,goes further: “The entire cate gory of AEDshas been insufficiently regulated by theFDA. The status quo essentially representsongoing, uncontrolled human experimentationwith no ethical oversight,” he says.The FDA is now considering whetherto remove the 510(k) loophole for AEDsand classify them as full Class III products.Despite claims from manufacturersthat reclassification will double or triplethe development time for new devices,the change seems likely to proceed.The FDA’s Shein agrees that the vastmajority of today’s AEDs are effective.“There is room for improvement, but itwould be a poor choice to leave an AEDhanging on the wall rather than applyingthe therapy to a patient,” he says. Rare failures,like that of the unit used on EugeneMalofiy, are of course distressing. But amuch bigger factor in the poor survivalrate from sudden cardiac arrest is the difficultyof getting access to an AED in the firstplace. In the United States, AEDs are usedin just 4 percent of sudden cardiac arreststhat occur in public places. One reason isthat AEDs are not always easily located;more on this later. Another deterrent isthat many AEDs are labeled “For use bytrained personnel only.” These labels arosebecause virtually all AEDs are prescription-onlydevices, bought under the authority—andresponsibility—of a medi cal officerat the airport, mall, or school. If an AEDwere somehow misused—or even correctlyused by someone not explicitly authorizedby the prescribing physician—that doctorcould be held legally liable and theoreticallyThe Most Accurate, Most RuggedTemperature Measurement.Ever.Up to ±3500V Isolation BarrierControlFPGAMEASURpoint provides isolationup to ±3500V continuously or 5000Vfor transients, protecting your analogsensor signals. Ethernet and applicationsoftware included.Not everyone favors reclassification.“AEDs are fine, technologically,” says GustBardy, a physician who helped to foundthe Seattle Institute for Cardiac Research(and is a consultant for Cardiac Science).“You can always find engineering problems,but patients in cardiac arrest arepredominantly going to die. There seemsto be an unrealistically high expectationthat these machines can reverse the processof death. The more restrictions oneputs on AEDs and the more demands forAED perfection, the fewer lives will actuallybe saved. Innovation will be pushedoverseas, and we’ll be stuck with AEDsthat are older and more expensive.”spectrum.ieee.orgMeasurement of temperature in industrial settings can provide bigsurprises. High common mode voltage from transients caused bynearby generators or motors can wipe-out instrumentation.ISO-channel technology makes temperature or voltagemeasurements almost indestructible, while providing accuracy of±0.15⁰C including all errors.Accurate measurements need protection.800-525-8528www.datatranslation.com/everMarch 2012 • IEEE Spectrum • NA 57


even lose his or her medical license.In fact, modern AEDs are safe and simpleenough for anyone to operate: A 1999study found that even untrained sixthgraders could use them nearly as effectivelyas trained paramedics. Also, GoodSamaritan laws cover the well-intentioneduse of public AEDs by lay peoplenationwide. But discouraging “traineduse” labels persist—even for public AEDsfound within buildings of the FDA itself.Worse still are stories of bystandersvainly seeking AEDs that werelocked away in offices or languishing inunmarked closets. The solution appearsto be education and openness. In 1998,Washington state began a citizen defibrillationprogram that included advertising,public training sessions, and thecreation of a detailed registry of AEDlocations around the state. The survivalrate for witnessed sudden cardiac arrestin Seattle is now more than 45 percent,compared with less than 0.5 percent inDetroit and 4 percent nationwide.If regional health authorities have muchPen n State | | OnlineSara Sara Davia Davia IacobucciSara Systems Sara Davia engineering Davia IacobucciGraduateSystems engineering Graduateearnearn a a Master’sMaster’s DegreeDegree inin ininSystemsSystems engineering—Onlineengineering—OnlineAdvance your your careerAdvance your your careerApply your your skills skills to to any any engineering disciplineApply your your skills skills to to any any engineering disciplineBuild Build professional network with with classmatesBuild Build a professional a network with with classmatesGain Gain high-quality education from from Penn State—a leaderGain Gain engineering a high-quality a educationeducation from from Penn Penn State—a leaderin engineering educationSeven-week courses over over six six semestersFinish Seven-weekin in as as little ascoursesas two two years over over six GRE’ssix semestersnot not requiredFinish in in as as little little as as two two years • • GRE’s not not requiredw w w . w. wo ro lrd lcd ac ma mp up s u. s p. sp u s . u e. de u d/ u I/ EI E EEto learn from Seattle, manu facturers coulddo with some inspiration, too. Critics complainthat AEDs lack the plug-and-playsimplicity of today’s consumer electronics.“Each manufacturer has different electrodesthat attach to the AED differently,”says Robyn Silverman of the ECRI Institute,a nonprofit organization that researchesmedical technologies. “When the next levelof care arrives, they might have anotherbrand of AED. Paramedics have to rip offthe first electrodes and put on new ones,which takes time. It would be nice to haveuniversal electrodes for any AED.”Then there’s the AEDs’ price: up to$2000. “If companies were able to producelow-cost AEDs that could be purchasedby nearly everybody, then you’dhave mass dissemination, like cellphones,”says Bardy. “But under the current regulatory,legal, and engineering burdens, it’snearly impossible to produce an AED thatcan be bought at Costco.”Ideas abound. BT Group (formerlyBritish Telecom, the United Kingdom’scommunications leader), has replacedobsolete wired telephones in some of itsiconic red phone boxes with public AEDs.And the San Ramon Valley Fire ProtectionDistrict, in California, has released one ofthe world’s first bystander CPR apps, forthe iPhone. Users of the app receive analert when anyone within 500 feet reportsa sudden cardiac arrest, along with a digitalmap pinpointing the location of boththe victim and the nearest public AED.Future AEDs might be integrated intoa program called Next-Generation 9-1-1,a federal initiative to expand emergencycommunications to include wireless andvoice-over-IP devices, text and video messaging,and geolocation data. Tomorrow’sAED could automatically summon paramedicsthe moment it’s activated.But the companies seem reluctant toinvest the necessary money. Says BrianWebster, of the AED maker Physio-Control: “The public access market is onlyabout 15 percent penetrated. The economicsof the market today do not support ourindustry doing core technology innovation.”Clearly, the AED industry is not in thebest of health. It’s ready for a good shockto the system. There are two on the way:reclassification by the FDA and a potentiallyindustry-shifting lawsuit. Whetherthese jolts will prove fatal or therapeuticremains to be seen.opost your co mments online athttp:// spectrum.ieee.org/aed031258 NA • iEEE Spectrum • March 2012 spectrum.ieee.orgU.Ed.OUT U.Ed.OUT 12-0187/12-WC-0120bkh/jms/sssU.Ed.OUT U.Ed.OUT 12-0187/12-WC-0120bkh/jms/sss

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