Medical Device Electromagnetic Interference: FDA Activities and Available Resources

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Medical Device Electromagnetic Interference FDA
Activities and Available Resources

• Don Witters
• Chairman, Center for Devices Radiological
  Health EMC Work Group
• Food and Drug Administration

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EMI Testing - Blackberry
BB in Pocket
Test Set up
Recorded Interference
HP Sonos 5500 Cardiac Ultrasound
Courtesy S. Juett Baylor Medical Center
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Active medical devices are vulnerable to EMI.
EMC, particularly with wireless technology, forms
the foundation toward solutions. Precise and
detailed information in adverse event reports are
key to developing EMC solutions.
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Outline

• FDA concerns for medical device EMI/EMC
• FDA activities toward EMC for RF wireless
  in/around medical devices
• EMC resources
• Needs and suggestions for EMI reporting
• Summary

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FDA Concerns for Medical Device EMC

• EMI has caused medical device malfunctions
  resulting in
• Death (suspected) and Serious Injury
• Suspected EMI related deaths with apnea monitors
• Misdiagnosis or Inappropriate Therapy
• Cell phone EMI to infusion pump
• EMI to IVD
• "Near Misses"
• Wireless medical telemetry

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Factors in Medical Device EMI

• EM source characteristics
• RF frequency, field strength, modulation
• Multiple EM sources
• Device susceptibility
• device function and pass bands
• leads and sensing
• EM environment and device use
• Wireless RF links with devices
• Lack of device EMC information

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Terminology

• Electromagnetic Interference (EMI)
• Can cause disruption of the device function by
• Electromagnetic energy (EM) in the form of
• Radiated EM (e.g. radio waves)
• Conducted (e.g. AC power surges)
• Electrostatic discharge (ESD)
• Electromagnetic Compatibility (EMC)
• Device functions properly in its EM environment
  (immunity), and the device EM emissions do not
  cause EMI in other devices

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Examples of Wireless Technology
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Considerations for Wireless Technology In and
Around Medical Devices

• Wireless is an RF transmitter source/victim for
  EMI
• Design and test device systems for EMC
• Assess device functions and wireless link for EMC
  risks
• Critical functions
• Data/command loss or corruption
• Manage and coordinate for EMC RF transmissions

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Activities Toward Medical Device EMC with
Wireless Technology

• Laboratory research
• Collaborations with FAA, U.S. Army Medical
  Command, Mobil Manuf. Forum
• AAMI EMC Committee
• Revision of AAMI TIR 18
• Participation by device manufacturers, JCAHO,
  users, wireless makers and carriers, MoHCA
• Regulatory review
• Coordination with JCAHO
• Asked JCAHO to make EMC part of certification
• Coordination with FCC

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Addressing EMC for Medical Devices

• How has manufacturer addressed EMC?
• Reference standard? (ex IEC 60601-1-22001)
• Deviations from standard
• Summary table emissions/immunity
• What was done why?
• test findings
• pass/fail criteria
• Device modifications
• Labeling (reference IEC 60601-1-22001)
• Address wireless connection
• EMC
• Wireless connection integrity
• Latency, through-put, security

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Wireless Medical Telemetry
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Addressing EMC/EMI in Healthcare Facilities

• http//www.fda.gov/cdrh/emc/emc-in-hcf.html
• Use available resources
• Assess environment and risks
• Manage RF sources
• Coordinate/communicate
• Educate staff, patients, visitors
• Establish policies
• Report incidents

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Resources

• Technical Information Report (TIR) 18, Guidance
  on Electromagnetic Compatibility of Medical
  Devices for Clinical/Biomedical Engineers. AAMI
  TIR 18-1997. Arlington, Virginia Association for
  the Advancement of Medical Instrumentation 1997.
  
• ANSI C63.18-1997, Recommended practice for an
  on-site, ad hoc test method for estimating
  radiated electromagnetic immunity of medical
  devices to specific radio-frequency transmitters.
  New York ANSI, 1997.
• Report of the American Medical Association (AMA)
  Council on Scientific Affairs and AMA
  recommendations to medical professional staff on
  the use of wireless radio-frequency equipment in
  hospitals.  Biomedical Instrumentation
  Technology. 200135189-195. (May/June)

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Concerns About EMI Event Reporting

• EMI not recognized as problem in facility or by
  reporters
• Device EMI can be intermittent, short-lived,
  hard to identify
• Reports not categorized for EMI and reports lack
  details
• Near misses likely under-reported
• Many facilities lack EMC policies and EMI
  reporting procedures
• Lack of facility follow-up on device problems
• No problem found

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Needs for EMI Reporting

• Awareness and education of facility staff
  reporters for EMI
• Consistent reporting of suspected EMI events
• Detailed and precise information in reports
• Identification of EM sources in vicinity of event
• Ex. all radio/wireless sources in the vicinity
• Any follow-up testing of device?
• Coordination within Facility
• policies for EMC and event reporting
• Staff coordination Administration, Inform.
  Technology (IT), Biomedical Eng., Clinicians,
  Nursing
• Patients, visitors

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Summary

• EMI with medical devices from wireless technology
  poses risks for patients
• Wireless technology can enhance and threaten
  active medical devices
• EMC and good reporting are keys to solutions
• EMI events not easy to recognize and are likely
  under-reported
• Need more precise and detailed event reporting
  for device EMI in the face of mass deployment of
  wireless technology

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EMI to medical devices from wireless technology
puts patients at risk. Consistent, precise, and
detailed event reports are needed to assess and
develop EMC solutions.Think EMC
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Donald Witters Center for Devices and
Radiological Health (HFZ-133) Food and Drug
Administration 12725 Twinbrook Parkway Rockville,
MD 20852 301/827-4955 dmw_at_cdrh.fda.gov