Toward Safe and Effective Wireless Medical Devices and Systems

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Toward Safe and Effective Wireless Medical
Devices and Systems

• Donald Witters
• Office of Science and Engineering Laboratories
• Center for Devices and Radiological Health
• Food and Drug Administration

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Safe, effective, reliable, and secure wireless
medical devices integrate risk management into
the design, testing, deployment and maintenance.
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Overview

• Risks for RF wireless medical devices
• Considerations to manage risks
• Challenges and opportunities
• Summary

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Wireless Medical Device Issues

• Wireless technology is dynamic changing
• EMC RF wireless is both a source and victim for
  EMI
• Competition/coexistence among users
• Convergence, interoperability
• Security
• Standards

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Key Terminology

• Radio frequency (RF) wireless medical device - a
  medical device that includes at least one
  function via RF wireless communications
• include data transfer, device control,
  programming, power transmission, remote sensing
  and monitoring, and identification

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WMTS
MedRadio (MICS)
DTV
Wireless Technology
Mobile Phones
Cognitive Radio
Mobile Radio
Wi-Fi
Bluetooth
NFC
Zigbee
WiMax
RFID
GPS
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Wireless Medical Devices
MRI 2
Hearing Aids 2
Endoscopic Surgical Tool 1
Doppler 1
Wireless Networking Accessory 2
Aspirator lt1
Hemodialysis 1
Wetness Detection 1
Urodynamic Measurement System lt1
Based on sample of 303 wireless medical devices.
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EMC and Wireless Technology Standards and
Documents

• IEC 60601-1-2 Medical Elect. equip.
• ISO 14708-1 Active implantable
• ISO 14117 (PC 69) pacemakers, ICDs

• IEEE 802.11, Bluetooth, Zigbee
• Cellular Telephone
• RFID
• MedRadio (MICS), WMTS

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EMC Terminology

• Electromagnetic Interference (EMI)
• Disruption of the device function by
• Electromagnetic energy (EM)
• 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) Device EM emissions do not cause EMI
  in other devices

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RFID Testing with Implantable Cardiac Pacemakers
Implantable cardiac pacemaker and lead
Inhibited ventricular stimulation
From S. Seidman et. al. In vitro tests reveal
sample radiofrequency identification readers
inducing clinically significant electromagnetic
interference to implantable pacemakers and
implantable cardioverter-defibrillators, JAMA
2010.
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Medical Device EMC Considerations

• Reference standards
• IEC 60601-1-2 std. covers most medical electrical
  equipment
• Active implants ISO 14117 (PC69), EN 45502,
  ISO14708-1
• Emissions and immunity testing
• important to include active wireless links
• test findings
• pass/fail criteria
• deviations from standard
• Device modifications
• User information
• IEC 60601-1-2 requirements

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Additional EMC Considerations

• Special Concerns
• Cell phones, Security systems, RFID
• MRI exposure
• Special environments?
• Present standards can be inadequate for wireless
  medical device concerns
• IEC 60601-1-2 3rd Ed. and IEC 61326-1 allow an
  exclusion from testing in the RF wireless
  frequency band
• IEC 60601-1-2 4th Ed. is different with immunity
  testing in common RF emitter bands

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Comparison of Sample Wired vs. Wireless Active
Medical Devices (Since 1996)
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Wireless Medical Device Considerations

• Overall risk management
• Choice of wireless technology
• Wireless functions performance
• Wireless data integrity
• Quality of Service
• Wireless Coexistence
• Wireless security
• EMC
• Information for user

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Final RF Wireless Medical Device Guidance

• http//www.fda.gov/MedicalDevices/DeviceRegulation
  andGuidance/GuidanceDocuments/ucm077210.htm
• Wireless technology not covered in this guidance
• MRI, X-ray, CT, RF/microwave diathermy

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Medical Wireless Risks Priorities
Life critical functions, high priority alarms,
therapy, remote control

• Shared risk environment
• Risk related to device/system intended use, and
  wirelessly enabled functions and needed
  performance
• Consequences of not getting data across wireless
  link correctly, timely, and securely

Risk
Low priority data, No therapy or alarms
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RF Frequencies Used by Wireless Medical Devices
Frequency
0-10KHz
10KHz - 100KHz
101KHz - 1MHz
1.1MHz - 10MHz
10.1MHz - 100MHz
402MHz - 405MHz
432MHz - 434MHz
608MHz - 614MHz
800MHz - 900MHz
916.5MHz
919.8MHz
1.395GHz - 1.4GHz
1.8GHz - 1.9GHz
Based on sample of 324 wireless medical devices
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Ex. Wireless User Information (1)
The X system was designed and tested for RF
wireless connections to an appropriately
configured and secured WLAN within the
Healthcare facility. The following equipment
and configurations were tested for wireless
connection and transmission of X system data and
information at the specified Quality of Service.
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Ex. Wireless User Information (2)

• Wireless Equipment needed for the X system
  wireless functions
• Model A1 Portable Data Terminal (PDT)
• X System was used for development and testing
  with the following features
• Integrated wireless technology IEEE 802.11b/g
  operating in the 2.4 GHz Industrial, Scientific,
  Medical (ISM) frequency band
• 64 MB RAM
• Integrated laser bar code reader
• RF wireless equipment needed to support a WLAN at
  the Healthcare facility
• - model B1 Dual Band Wireless Access Point
  certified for IEEE 802.11b/g technology
• - Integrated PC Network Cards certified for IEEE
  802.11b/g technology

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Wireless Protocol Used by Medical Devices
GSM/GPRS 1
Medical Implant Communication Service 1
Medical Device Telemetry Service lt1
Ultra Wideband Frequency Spectrum 1
NRMI (Near Field Magnetic Induction) lt1
Based on sample of 326 wireless medical devices
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Example QoS Information (1)
Understanding Wireless LAN Quality of Service To
achieve the same level of wireless quality of
service demonstrated during testing wireless X
device system needs the following service
Maintain the network according to IEEE
802.11a/b/g standards with encryption. Traffic
on the 802.11 wireless network does not peak at
more than sixty percent (60) for a sustained
interval of thirty (30) seconds or more when
measured over any continuous six (6) hour period.
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Example QoS Information (2)
Understanding Wireless LAN Quality of Service
(cont.) Handheld devices for the wireless X
device system must be configured to 802.11b or
802.11g, channel 6. Minimum available data rate
at the desired location of service must be 2
Mbs. Recommended wireless network security
protocol of WPA2 encryption. The wireless LAN
must have a minimum of two (2) wireless access
points with a physical separation of no more than
50 m. Handheld devices for the wireless X
device system must be at least one (1) meter and
no more than twenty-five (25) meters from a
wireless access point to maintain connectivity.
The error rate of data transfer must be less than
2 dropped packets.
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Coexistence Testing
Sample wireless interferer
Device wireless link
Sample wireless interferer
Distance orientation
Sample wireless interferer
Sample wireless interferer
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Wireless Security Considerations

• Wireless security issues
• Open architecture
• Multiple combinations of technology
• Rogue wireless users
• Health Insurance Portability and Accountability
  Act (HIPAA) issues
• Wireless security considerations
• Authentication to ensure authorized users
• Encryption to secure sensitive data and
  wireless links

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Security of Wireless Signals and Data

• Approaches
• Part of comprehensive security plan and
  procedures
• see FDAs draft guidance Content of Premarket
  Submissions for Management of Cybersecurity in
  Medical Devices. (http//www.fda.gov/MedicalDevic
  es/DeviceRegulationandGuidance/GuidanceDocuments/u
  cm356186.htm)
• Use the most up-to-date wireless security
  encryptions

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Ex. Wireless Security Information (1)
Wireless Security and SSID The WPA2 wireless
security encryption protocol is strongly
recommended for all users of the X medical device
system in addition to all other security
protocols and procedures that are used by the
healthcare facility systems.
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Ex. Wireless Security Information (2)
Wireless Security and SSID The X wireless medical
device system was designed and tested to work
with wirelessly enabled platforms using the IEEE
802.11b/g protocols, which runs under a network
ID (SSID) that is broadcast by default to 802.11
capable hardware. To securely operate X wireless
medical device system it is recommended that the
wireless broadcasting of the SSID be disabled so
that only devices communicating over the
Healthcare facility defined SSID can transmit
and receive on the same network.
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Information for Set-up and Use

• Information to properly configure, deploy, use
  and maintain the wireless device system
• Wireless functions and performance
• Limitations, environments, proximity of other
  wireless, international regulations if
  appropriate
• Specific wireless technology (e.g., IEEE
  802.11b/g/a), frequencies, wireless modulations,
  effective radiated RF power
• QoS, recommended security information (e.g. WPA2)
• EMI recognition mitigation information
• FCC labeling as appropriate

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Maintaining the Wireless Device

• Device Life Cycle
• EMI/EMC issues
• Accessories, additional equipment (e.g. modems)
• Repeated failures at same location or other
  locations
• Servicing
• Maintaining wireless integrity and performance

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Challenges and Opportunities

• Rapidly changing wireless technology, limited
  spectrum
• Wider integration and greater need for shared
  risk management
• Increase in home health care with more functions
  and less on-site management
• Need for information and standards for safe,
  secure, and reliable medical systems
• Opportunity to create products and pathways for
  wireless in healthcare

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Summary

• Medical wireless technology is rapidly evolving
  and helping to drive innovation in health care.
• Safe, secure, and reliable wireless medical
  systems require risk management.

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Summary

• Considerations for wireless medical systems
  include
• Wireless technology, functions and
  characteristics
• QoS, data integrity, coexistence, security, EMC,
  user information maintenance
• Many challenges and opportunities for research,
  products, standards, and guidance to meet present
  and future needs.

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Safe, secure, and reliable wireless medical
device systems require risk awareness and
management focused on key considerations
including wireless performance, security, and
EMC.
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Donald Witters Center for Devices and
Radiological Health, Food and Drug
Administration 10903 New Hampshire Ave. Building
62, Room 1130 Silver Spring, MD
20993-0002 USA Phone [phone] donald.witters_at_
fda.hhs.gov
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FDA Semi-Anechoic Chamber