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Overview of Standards for External Defibrillators:
Role of FDA
Charles Ho, Ph.D.
FDA/CDRH/ODE
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Outline
1.1. Why use standards? Why use standards? 2.2. FDA’s role in standardsFDA’s role in standards3.3. List of major standardsList of major standards4.4. Limitations of standards Limitations of standards
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1. Why use standards?
Standards facilitate communications in Standards facilitate communications in pre-market reviews. pre-market reviews.
Standards provide test protocols with Standards provide test protocols with pass/fail criteria, which form a common pass/fail criteria, which form a common language between manufacturers and language between manufacturers and FDA for substantiating claims.FDA for substantiating claims. No need No need to re-invent the wheel each time.to re-invent the wheel each time.
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Example: To claim adequate battery capacity to power a defibrillator
Reference: ANSI/AAMI DF80, clause Reference: ANSI/AAMI DF80, clause 102.2 102.2 Protocol: At O°C, the battery should Protocol: At O°C, the battery should enable the defibrillator to deliver at least 20 enable the defibrillator to deliver at least 20 shocks at the maximum shock energy.shocks at the maximum shock energy. [O°C test is more demanding than room O°C test is more demanding than room temperature test.]temperature test.]
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Standards also facilitate standardization of device Standards also facilitate standardization of device specifications among device manufacturers. specifications among device manufacturers.
May lead to standardizing certain features, like May lead to standardizing certain features, like pad connections and the user interface. pad connections and the user interface.
But need to be in sufficient detail to allow But need to be in sufficient detail to allow interpretation by both design engineers and FDA.interpretation by both design engineers and FDA.
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Remember, most standards Remember, most standards concerning external defibrillators are concerning external defibrillators are voluntary.voluntary.
The only mandatory standard for an The only mandatory standard for an external defibrillator is the Performance external defibrillator is the Performance Standard for Electrode Lead Wires and Standard for Electrode Lead Wires and Patient Cables, 21 CFR 898.Patient Cables, 21 CFR 898.
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2. FDA’s Role in Standards
Although FDA had been involved in the Although FDA had been involved in the development and use of medical development and use of medical device standards for decades, the device standards for decades, the Food and Drug Administration Food and Drug Administration Modernization Act (FDAMA) of 1997 Modernization Act (FDAMA) of 1997 formalized the process.formalized the process.
* Above statement adapted from FDA website.
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FDA liaisons attend standard FDA liaisons attend standard committee meetings, participate in committee meetings, participate in discussions and vote on proposed discussions and vote on proposed standards, in order that the standards, in order that the resultant standards may be more resultant standards may be more acceptable to both the industry acceptable to both the industry and the FDAand the FDA..
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Dr. Oscar Tovar is our Primary Dr. Oscar Tovar is our Primary Liaison for standards on external Liaison for standards on external defibrillators at the AAMI DF defibrillators at the AAMI DF Committee and the IEC Committee and the IEC TC 62/SC TC 62/SC 62D/MT 19 62D/MT 19 Committee.Committee.
Dr. Richard Gray is the Alternate Dr. Richard Gray is the Alternate LiaisonLiaison..
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The FDA has only one vote in The FDA has only one vote in each standards committee, just each standards committee, just like any other entity. Thus, some like any other entity. Thus, some standards may not be 100% standards may not be 100% acceptable to FDA. acceptable to FDA.
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In that case, FDA recognizes only In that case, FDA recognizes only the parts of a standard that FDA the parts of a standard that FDA agrees with, and declines to agrees with, and declines to recognize the parts that FDA does recognize the parts that FDA does not agree withnot agree with. .
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Recognition of a standard
By recognizing a standard, or By recognizing a standard, or parts of a standard, FDA indicates parts of a standard, FDA indicates that we have reviewed the that we have reviewed the standard and found it mostly standard and found it mostly acceptable for substantiating acceptable for substantiating claims made in a premarket claims made in a premarket submittal.submittal.
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Example: A 510(k) claiming Example: A 510(k) claiming adequate battery capacity adequate battery capacity provides a test report using AAMI provides a test report using AAMI DF80, clause 102.2. And FDA DF80, clause 102.2. And FDA can review this test very quickly.can review this test very quickly.
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If a manufacturer chooses not to comply If a manufacturer chooses not to comply with an FDA recognized standard, or with an FDA recognized standard, or tests a defibrillator using clauses in the tests a defibrillator using clauses in the standard that FDA declines to recognize, standard that FDA declines to recognize, FDA will still review the premarket FDA will still review the premarket submittal on a case by case basis. submittal on a case by case basis.
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Consequently, FDA will have to review the Consequently, FDA will have to review the unrecognized clauses in a recognized standard, unrecognized clauses in a recognized standard, or the unfamiliar test protocols in a or the unfamiliar test protocols in a unrecognized standard from the ground up. unrecognized standard from the ground up. This may generate a lot of basic questions to This may generate a lot of basic questions to clarify terms or rationale for a certain test clarify terms or rationale for a certain test protocol, usually resulting in more work for both protocol, usually resulting in more work for both the manufacturer and FDA.the manufacturer and FDA.
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3. List of Major Standards for External Defibrillators
(non-exhaustive list)(non-exhaustive list)
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Hardware
ANSI/AAMI DF80: Medical electrical equipment ANSI/AAMI DF80: Medical electrical equipment - Part 2-4: Particular requirements for the safety - Part 2-4: Particular requirements for the safety of cardiac defibrillators (including automated of cardiac defibrillators (including automated external defibrillators)external defibrillators)
-- the most commonly used standard in submittals -- the most commonly used standard in submittals on external defibrillators on external defibrillators
-- covers most hardware safety and effectiveness -- covers most hardware safety and effectiveness specifications, except waveform effectivenessspecifications, except waveform effectiveness
IEC counterpart:IEC counterpart: IEC 60601-2-4: Medical electrical equipment - IEC 60601-2-4: Medical electrical equipment -
Part 2-4: Particular requirements for the safety Part 2-4: Particular requirements for the safety of cardiac defibrillators and cardiac defibrillator-of cardiac defibrillators and cardiac defibrillator-monitorsmonitors
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For general safety:For general safety: IEC 60601-1: Medical Electrical IEC 60601-1: Medical Electrical
Equipment - Part 1: General Equipment - Part 1: General Requirements For Safety 1: Collateral Requirements For Safety 1: Collateral Standard: Safety Requirements for Standard: Safety Requirements for Medical Electrical SystemsMedical Electrical Systems
For electromagnetic compatibility (EMC):For electromagnetic compatibility (EMC): IEC 60601 -1-2: IEC 60601 -1-2: Medical Electrical Medical Electrical
Equipment - PART 1: General Equipment - PART 1: General Requirements For Safety 2. Collateral Requirements For Safety 2. Collateral Standard: Electromagnetic Compatibility - Standard: Electromagnetic Compatibility - Requirements and TestsRequirements and Tests
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BiocompatibilityBiocompatibility
[for defibrillator electrodes (pads or [for defibrillator electrodes (pads or paddles):]paddles):]
ISO 10993 – 5: Biological evaluation ISO 10993 – 5: Biological evaluation of medical devices -- Part 5: Tests for of medical devices -- Part 5: Tests for in vitro cytotoxicityin vitro cytotoxicity
ISO 10993-10 Biological evaluation of ISO 10993-10 Biological evaluation of medical devices — Part 10: Tests for medical devices — Part 10: Tests for irritation and delayed-type irritation and delayed-type hypersensitivity (sensitization)hypersensitivity (sensitization)
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Environmental testing:Environmental testing: IEC 60068-2-27: Environmental testing - IEC 60068-2-27: Environmental testing -
Part 2-27: Tests - Test Ea and guidance: Part 2-27: Tests - Test Ea and guidance: ShockShock
IEC 60068-2-6: Environmental testing - IEC 60068-2-6: Environmental testing - Part 2: Tests - Test Fc: Vibration Part 2: Tests - Test Fc: Vibration (sinusoidal)(sinusoidal)
IEC 60529 Degrees of protection IEC 60529 Degrees of protection provided by enclosures (IP Code). provided by enclosures (IP Code). [protection against rain and dust][protection against rain and dust]
For sample list of standards, see handout.For sample list of standards, see handout.
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4. Limitations of standards
Standards do not cover every aspect of Standards do not cover every aspect of the external defibrillator. For example, the external defibrillator. For example, there is no clinical or animal study there is no clinical or animal study protocol in the AAMI DF80 standard.protocol in the AAMI DF80 standard.
(However, an informative annex DD in DF80 has some historical notes on clinical studies.)
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Further, it is widely accepted that Further, it is widely accepted that biphasic waveforms are superior to biphasic waveforms are superior to monophasic waveforms and result in monophasic waveforms and result in improved patient survival. But the improved patient survival. But the standard that covers basic safety and standard that covers basic safety and effectiveness requirements, AAMI effectiveness requirements, AAMI DF80, does not prohibit monophasic DF80, does not prohibit monophasic waveforms.waveforms. A new defibrillator with this old technology can still claim compliance with DF80.
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Lastly, some standards permit a large Lastly, some standards permit a large leeway in designing the defibrillator, leeway in designing the defibrillator, so that performance could vary so that performance could vary considerably from manufacturer to considerably from manufacturer to manufacturer.manufacturer.
An example is the difference between delivered energy and selected energy in a defibrillator.
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[From DF80, clause 2.12.101] [From DF80, clause 2.12.101] Delivered energy Delivered energy = shock energy actually delivered to a patient= shock energy actually delivered to a patient [From clause 2.12.106] [From clause 2.12.106] Selected energy Selected energy = energy intended to be delivered, as = energy intended to be delivered, as determined by the setting of a control determined by the setting of a control Usually, this is the energy shown in the energy Usually, this is the energy shown in the energy dial of the defibrillator front panel.dial of the defibrillator front panel.
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However, the selected energy is However, the selected energy is specified for the 50 ohm load only. For specified for the 50 ohm load only. For all other loads, the manufacturer just all other loads, the manufacturer just has to specify the selected energies in has to specify the selected energies in the device manual. the device manual.
Additionally, the verification test Additionally, the verification test protocol allows a ± 15% tolerance in protocol allows a ± 15% tolerance in testing the measured delivered energy testing the measured delivered energy against the specified selected energy.against the specified selected energy.[clauses 6.3 aa, 6.8.3 aa and 50.2][clauses 6.3 aa, 6.8.3 aa and 50.2]
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These two layers of tolerance These two layers of tolerance combine to allow delivered energy combine to allow delivered energy values that may be very different values that may be very different from the selected energies on the from the selected energies on the energy dial, for loads other than energy dial, for loads other than 50 ohm. Yet not every patient is a 50 ohm. Yet not every patient is a 50 ohm load to the defibrillator. 50 ohm load to the defibrillator.
Still compliant with DF80!Still compliant with DF80!
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ConclusionThis presentation has briefly described This presentation has briefly described FDA’s use of standards for external FDA’s use of standards for external defibrillators, and the standards’ defibrillators, and the standards’ limitations. It is hoped that everyone limitations. It is hoped that everyone can keep these in mind as we move can keep these in mind as we move forward in this field.forward in this field.