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
Safe, effective, reliable, and
secure wireless medical devices
integrate risk management into
the design, testing, deployment
and maintenance.
2
Overview

Risks for RF wireless medical
devices

Considerations to manage risks

Challenges and opportunities

Summary
3
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
4
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
5
WMTS
DTV
MedRadio
(MICS)
Wireless Mobile
Phones
Cognitive
Technology
Radio
Bluetooth
Wi-Fi
Mobile
Radio
NFC
Zigbee
WiMax
RFID
GPS
Wireless Medical Devices*
MRI
Hearing Aids
Endoscopic Surgical
Tool
Doppler
Wireless Networking
Accessory
Aspirator
Hemodialysis
Wetness Detection
Urodynamic
Measurement System
2%
2%
1%
1%
2%
<1%
1%
1%
<1%
*Based on sample of 303 wireless medical devices.
7
EMC and Wireless Technology
Standards and Documents
Medical
device
EMC
•IEC 60601-1-2 Medical Elect.
equip.
•ISO 14708-1 Active implantable
•ISO 14117 (PC 69) pacemakers,
ICDs
Wireless
Technology
•IEEE 802.11, Bluetooth,
Zigbee
•Cellular Telephone
•RFID
•MedRadio (MICS),
WMTS
8
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
9
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.
10
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
11
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
12
Comparison of Sample Wired vs. Wireless Active
Medical Devices (Since 1996)
13
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
14
Final RF Wireless Medical Device Guidance
http://www.fda.gov/Med
icalDevices/DeviceRegul
ationandGuidance/Guida
nceDocuments/ucm0772
10.htm
Wireless technology not
covered in this guidance:
MRI, X-ray, CT,
RF/microwave diathermy
15
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
Low priority data, No therapy
correctly, timely, and securely
or alarms

16
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
17
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.
18
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
19
Wireless Protocol Used by Medical
Devices*
*Based on sample of 326 wireless medical devices
GSM/GPRS
Medical
Implant
Communication
Service
Medical Device
Telemetry
Service
Ultra Wideband
Frequency
Spectrum
NRMI (Near
Field Magnetic
Induction)
1%
1%
<1%
1%
<1%
20
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.
21
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
22
packets.
Coexistence Testing
Sample wireless interferer
Device wireless link
Sample wireless interferer
Distance & orientation
Sample wireless interferer
Sample wireless interferer
23
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
24
Security of Wireless Signals and Data
•
Approaches
• Part of comprehensive security plan and
procedures
• see FDA’s draft guidance “Content of
Premarket Submissions for Management of
Cybersecurity in Medical Devices.”
(http://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/
GuidanceDocuments/ucm356186.htm)
•
Use the most up-to-date wireless security
encryptions
25
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.
26
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.
27
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
28
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
29
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
30
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.

31
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.
32
Safe, secure, and reliable wireless
medical device systems require risk
awareness and management
focused on key considerations
including wireless performance,
security, and EMC.
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: 301/796-2483
donald.witters@fda.hhs.gov
FDA Semi-Anechoic Chamber