HDTV Test Causes Interference At Hospitals
MINNEAPOLIS, MINNESOTA, U.S.A., 1998 MAR 13 (NB) -- By
Leonard Lee A test of a high definition television (HDTV) transmission
in Dallas knocked out the radio signals from 12 wireless heart monitors
at the nearby Baylor University Medical Center. The monitors feed
telemetry information from patients recovering from heart surgery to a
central nurses' station.
At 1:27pm on February 27, the central monitoring unit gave an error
message saying it was no longer receiving telemetry signals from the
patients. Nurses immediately rushed to verify the status of each patient
while technicians set up a backup monitoring system. Using spectrum
analyzers, technicians attempted to trace the source of the problem, but
were confounded because the interfering signal was intermittent.
Over the course of the next few days, engineers tracked the
interference to a series of HDTV test broadcasts from nearby
WFAA-TV. Steve Juett, senior clinical engineer at BUMC, told
Newsbytes that "our supervisor of TV services at Baylor recognized this
as the HDTV signal because he had seen a newscast announcing the
HDTV test."
According to Juett, several other area hospitals were similarly affected.
The Dallas-Fort Worth Hospital Council contacted the FCC and FDA to
inform them of the problem. An FCC spokesman told Newsbytes the
problem is not with the HDTV technology itself, but that HDTV
broadcasts are assigned to previously unused channel spectrum in each
city. In this case, WFAA, which normally broadcasts on channel 8, will
be using channel 9 for its HDTV.
Juett said that, although patients were not endangered, it is a potentially
serious problem. "Should there not be safeguards and backup plans,"
Juett said, "the potential is there that the staff could be distracted enough
to allow a health care incident."
The FCC was aware of potential interference problems when it
assigned channels 7-13 and 14-46 for use by biomedical telemetry
devices last October, and hospitals were warned that HDTV tests
would soon be starting in major cities.
According to FCC rules, it is the responsibility of health care facilities
and medical device manufacturer to monitor potential interference
problems, even if it means having to stop using the monitoring equipment
involved. Biomedical telemetry devices are considered secondary
devices, meaning priority for any part of the broadcast spectrum that
they are assigned remains with broadcasters.
FCC Rule 15, as amended last October, reads in part: "the operator of
the biomedical telemetry device must accept whatever level of
interference is received from other radio operations. The operator, i.e.,
the health care facility, is responsible for resolving any interference that
occurs subsequent to the installation of these devices." Baylor University
plans to purchase new monitors at a cost of $200,000 to avoid any future
interference problems.
FCC officials told Newsbytes they recognize the need to improve
outreach to make sure health care facilities are aware of potential
interference problems.
Bruce Franca, deputy director of the FCC's Office of Engineering and
Technology said, "We want to make sure health care facilities, medical
device manufacturers, and the broadcast industry all use their resources
to get the word out about the new assignment of TV channels in picking
frequencies for biomedical telemetry devices."
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