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					Overview of Standards for
 External Defibrillators:
      Role of FDA
     Charles Ho, Ph.D.
      FDA/CDRH/ODE
   Charles.ho@fda.hhs.gov

                            1
         Outline
1.   Why use standards?
2.   FDA’s role in standards
3.   List of major standards
4.   Limitations of standards




                                2
   1. Why use standards?
Standards facilitate communications in
pre-market reviews.
Standards provide test protocols with
pass/fail criteria, which form a common
language between manufacturers and
FDA for substantiating claims. No need
to re-invent the wheel each time.

                                          3
Example:
To claim adequate battery capacity to
power a defibrillator
Reference: ANSI/AAMI DF80, clause
102.2
Protocol: At O°C, the battery should
enable the defibrillator to deliver at least
20 shocks at the maximum shock energy.
[O°C test is more demanding than room
temperature test.]

                                               4
Standards also facilitate standardization of device
specifications among device manufacturers.

May lead to standardizing certain features, like
pad connections and the user interface.

But need to be in sufficient detail to allow
interpretation by both design engineers and FDA.



                                                      5
Remember, most standards
concerning external defibrillators are
voluntary.
The only mandatory standard for an
external defibrillator is the Performance
Standard for Electrode Lead Wires and
Patient Cables, 21 CFR 898.



                                            6
 2. FDA’s Role in Standards
Although FDA had been involved in the
development and use of medical
device standards for decades, the
Food and Drug Administration
Modernization Act (FDAMA) of 1997
formalized the process.

* Above statement adapted from FDA website.



                                              7
FDA liaisons attend standard
committee meetings, participate in
discussions and vote on proposed
standards, in order that the
resultant standards may be more
acceptable to both the industry
and the FDA.



                                     8
Dr. Oscar Tovar is our Primary
Liaison for standards on external
defibrillators at the AAMI DF
Committee and the IEC TC 62/SC
62D/MT 19 Committee.

Dr. Richard Gray is the Alternate
Liaison.



                                    9
The FDA has only one vote in
each standards committee, just
like any other entity. Thus, some
standards may not be 100%
acceptable to FDA.




                                    10
In that case, FDA recognizes only
the parts of a standard that FDA
agrees with, and declines to
recognize the parts that FDA does
not agree with.




                                    11
 Recognition of a standard
By recognizing a standard, or
parts of a standard, FDA indicates
that we have reviewed the
standard and found it mostly
acceptable for substantiating
claims made in a premarket
submittal.

                                     12
Example: A 510(k) claiming
adequate battery capacity
provides a test report using AAMI
DF80, clause 102.2. And FDA
can review this test very quickly.




                                     13
If a manufacturer chooses not to comply
with an FDA recognized standard, or
tests a defibrillator using clauses in the
standard that FDA declines to recognize,
FDA will still review the premarket
submittal on a case by case basis.




                                             14
Consequently, FDA will have to review the
unrecognized clauses in a recognized standard,
or the unfamiliar test protocols in a
unrecognized standard from the ground up.
This may generate a lot of basic questions to
clarify terms or rationale for a certain test
protocol, usually resulting in more work for both
the manufacturer and FDA.



                                                15
3. List of Major Standards for
    External Defibrillators
      (non-exhaustive list)




                                 16
                     Hardware
 ANSI/AAMI DF80: Medical electrical equipment
  - Part 2-4: Particular requirements for the safety
  of cardiac defibrillators (including automated
  external defibrillators)

-- the most commonly used standard in submittals
     on external defibrillators
-- covers most hardware safety and effectiveness
     specifications, except waveform effectiveness

IEC counterpart:
 IEC 60601-2-4: Medical electrical equipment -
   Part 2-4: Particular requirements for the safety
   of cardiac defibrillators and cardiac defibrillator-
   monitors                                               17
For general safety:
 IEC 60601-1: Medical Electrical
   Equipment - Part 1: General
   Requirements For Safety 1: Collateral
   Standard: Safety Requirements for
   Medical Electrical Systems

For electromagnetic compatibility (EMC):
 IEC 60601 -1-2: Medical Electrical
   Equipment - PART 1: General
   Requirements For Safety 2. Collateral
   Standard: Electromagnetic Compatibility -
   Requirements and Tests

                                               18
             Biocompatibility
    [for defibrillator electrodes (pads or
                     paddles):]


 ISO 10993 – 5: Biological evaluation
  of medical devices -- Part 5: Tests for
  in vitro cytotoxicity
 ISO 10993-10 Biological evaluation of
  medical devices — Part 10: Tests for
  irritation and delayed-type
  hypersensitivity (sensitization)
                                             19
         Environmental testing:
 IEC 60068-2-27: Environmental testing -
  Part 2-27: Tests - Test Ea and guidance:
  Shock
 IEC 60068-2-6: Environmental testing -
  Part 2: Tests - Test Fc: Vibration
  (sinusoidal)
 IEC 60529 Degrees of protection
  provided by enclosures (IP Code).
  [protection against rain and dust]

  For sample list of standards, see handout.
                                             20
4. Limitations of standards
Standards do not cover every aspect of
the external defibrillator. For example,
there is no clinical or animal study
protocol in the AAMI DF80 standard.
(However, an informative annex DD in
DF80 has some historical notes on
clinical studies.)

                                           21
Further, it is widely accepted that
biphasic waveforms are superior to
monophasic waveforms and result in
improved patient survival. But the
standard that covers basic safety and
effectiveness requirements, AAMI
DF80, does not prohibit monophasic
waveforms.
A new defibrillator with this old
technology can still claim compliance
with DF80.
                                        22
Lastly, some standards permit a large
leeway in designing the defibrillator,
so that performance could vary
considerably from manufacturer to
manufacturer.
An example is the difference between
delivered energy and selected energy
in a defibrillator.
                                         23
[From DF80, clause 2.12.101]
Delivered energy
= shock energy actually delivered to a patient

[From clause 2.12.106]
Selected energy
= energy intended to be delivered, as
  determined by the setting of a control
Usually, this is the energy shown in the energy
dial of the defibrillator front panel.

                                                  24
However, the selected energy is
specified for the 50 ohm load only. For
all other loads, the manufacturer just
has to specify the selected energies in
the device manual.

Additionally, the verification test
protocol allows a ± 15% tolerance in
testing the measured delivered energy
against the specified selected energy.
[clauses 6.3 aa, 6.8.3 aa and 50.2]

                                          25
These two layers of tolerance
combine to allow delivered energy
values that may be very different
from the selected energies on the
energy dial, for loads other than
50 ohm. Yet not every patient is a
50 ohm load to the defibrillator.
Still compliant with DF80!
                                     26
           Conclusion
This presentation has briefly described
FDA’s use of standards for external
defibrillators, and the standards’
limitations. It is hoped that everyone
can keep these in mind as we move
forward in this field.



                                          27

				
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