(You are encouraged to copy and distribute this Advisory)
| March 20, 1998 |
| To: | Director, Clinical/Biomedical Engineering
Risk Manager Hospital Administrator Nursing Home Director |
FDA has recently become aware of incidents involving digital television
(DTV) transmissions interfering with medical telemetry systems
that use TV channels. The purpose of this Advisory is to alert
you to the potential for this problem and provide recommendations
for your facility. In one case the telemetry system was operating
on a TV channel which had been unused for many years but had been
recently re-assigned by the Federal Communications Commission
(FCC) to a TV station in the vicinity of the hospital for DTV.
The new TV signal interfered with the hospital's telemetry system
and rendered it unusable. A second hospital in the same city
was also affected.
Many medical telemetry devices are operated under 47 CFR Part
15 of the FCC regulations. These devices are secondary users
of the radio-frequency (RF) spectrum. Licensed users such as
television stations are the primary users. As a secondary
user, your telemetry devices may be subject to interference from
the primary user at any time, but must not cause interference
with the primary user. If your telemetry devices are operating
on frequencies licensed to a primary user, you need to be aware
of the potential for interference and take any steps necessary
to avoid device malfunctions due to interference.
Medical telemetry devices have shared the TV broadcast spectrum
on channels 7-13 for many years. Last October FCC authorized
the operation of medical telemetry devices on much more of the
TV broadcasting spectrum. However, at this time most medical
telemetry systems are still believed to operate on the original
channels 7-13.
In the next six months, 10 major market areas for DTV will begin
transmitting signals on previously unused channels. Although
most of these first DTV stations will operate outside the channel
7-13 band, some will be broadcasting within that band. Many more
DTV stations will be on line by 2003 and could begin transmitting
at any time. The latest information on which channels have been
allocated to TV stations is listed by geographic location in an
FCC table of allotments. This table can be found on the FCC website
by going to www.fcc.gov/Bureaus/Engineering_Technology/News_Releases/1998/
nret8002.html (this address is upper/lower case sensitive),
then selecting DTV Table of Allotments (view in either WordPerfect
version or Acrobat version to see table headings). Facilities
using medical telemetry systems should consult this table to determine
the channel allotments for TV stations in their area.
To address potential interference problems for medical telemetry
systems, FDA recommends that you work with the manufacturer of
your telemetry systems to:
If your telemetry systems are transmitting on channels that are
scheduled to be used by a local station, you should work with
the manufacturer of your telemetry systems to:
If you find that your telemetry systems are transmitting on channels
that will remain unused, you should not have a problem due to
DTV transmissions. However, you should periodically check
the FCC allotments to assure that those channels remain available.
The Safe Medical Devices Act of 1990 (SMDA) requires hospitals
and other user facilities to report deaths and serious illnesses
and injuries associated with the use of medical devices. Thus,
if interference with a medical device results in a death or serious
injury, it must be reported. We request that you follow the procedures
established by your facility for such mandatory reporting.
If a telemetry system fails to function due to electromagnetic
interference or any other reason, it is a device malfunction.
Such malfunctions should be reported to the manufacturer or can
be reported directly to MedWatch, the FDA's voluntary reporting
program. Submit these reports to MedWatch: by telephone at
1-800-FDA-1088, by FAX at 1-800-FDA-0178, or by mail to MedWatch,
Food and Drug Administration, HF-2, 5600 Fishers Lane, Rockville,
MD 20857.
If you have any questions regarding this Advisory which are related
to FDA issues, please contact Nancy Pressly, CDRH, Office of Surveillance
and Biometrics, HFZ-510, 1350 Piccard Drive, Rockville, MD 20850,
FAX 301-594-2968, or e-mail nap@cdrh.fda.gov.
For additional information regarding FCC issues, please contact
Julius P. Knapp, FCC, Office of Engineering and Technology, 1919
M Street, NW, Washington, D.C., 20554, FAX 202-418-1944, or e-mail
jknapp@fcc.gov.
Additional copies of this Advisory can be found on the FDA webpage
at www.fda.gov/cdrh/safety.html. Further information regarding
electromagnetic interference and medical devices can be found
on our EMC webpage at www.fda.gov/cdrh/emc/index.html. If interested
in receiving Safety Alerts, Public Health Advisories and other
FDA medical device safety notices by e-mail when they are released,
subscribe to our listserver. To subscribe, visit the page http://service.govdelivery.com/service/subscribe.html?code=USFDACDRH_10
|
Sincerely yours, D. Bruce Burlington, M.D. Director Center for Devices and Radiological Health |
Updated March 20, 1998
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