Biomedical Engineering Reference
In-Depth Information
huge stress on the facility's ability to serve its
patients and provide safe and effective healthcare.
During a routine business day, hospitals have a
variety of means for communicating internally and
with other hospitals, emergency medical systems
(EMS), vendors, suppliers, health departments,
as well as patients and their families. If this is
disrupted, because of a large mass-casualty inci-
dent, a natural or man-made disaster, or even just
a technological failure, communications becomes
a huge problem. Building communication redun-
dancy and flexibility into the hospital response
system is a vital necessity. There are a variety of
ways to do this:
UHF/VHF/HF—These terms indicate various
bands of the radio spectrum, each with
its own characteristics for distance, penetra-
tion, and inter-agency communication. Ultra-
high frequency (UHF: 300-3000MHz) has
shorter wave-length, but greater penetra-
tion within a building; Very-high Frequency
(VHF: 30-300MHz), has somewhat longer
wave-length and distance, but works less
well within the facility compound. High-
frequency (HF: 1.8-30.0MHz) is used for
long-distance communications—across state
or national boundaries, depending on the
frequency band and antenna used [7].
(a) Most hospitals already have a variety of
radio communication systems, in addition to
the normal land-line and cellular telephone
systems. Sometimes these radio systems can
take up the slack, but often they become
overloaded as well. The Hospital Emergency
Administrative Radio (HEAR) system is rela-
tively common across the United States in
hospitals and EMS units. It is often used for
EMS units to notify hospitals that there are
incoming casualties or patients. This system
was developed in the 1970s and not much
has been done to modify it, although there is
some newer equipment available. The tech-
nology is old enough that it is unlikely that it
can ever be brought up to current interoper-
ability standards (APCO-25) [6]. Other radio
systems, in addition to, or replacement of, the
HEAR system include UHF, VHF, 800MHz,
and others commonly used by public safety
agencies (Fire, EMS, police). These are
used for day-to-day to communicate with
the hospitals, but often become overloaded
when some unanticipated large-scale event
occurs.
(b) HF issues—there are a number of tech-
nological challenges to be aware of when
using HF frequencies in the healthcare envi-
ronment. Radios which transmit on these
frequencies are often higher-powered than
those on the UHF and VHF bands, and
the antennas often have a stronger radiation
pattern, which have the potential to interfere
with medical telemetry and other biomedical
equipment. Careful location and polariza-
tion of the antenna in or above patient-care
areas needs to be taken into consideration
when installing HF radios in a hospital
setting.
Communication systems for hospitals, and
other health-care entities, depend on reliability,
constancy, and redundancy. Systems need to be
reliable; they need to be there all the time and they
need to be redundant. There are multiple exam-
ples of how systems can fail; what other systems
can replace or supplement them, and, when all else
fails, who comes to the rescue.
Examples: Why
not put in actual hospital
names and references to news articles? Hurricaine
Katrina?
Mostly they are anecdotal from local
experiences, and were not ever publicized.
•
The Amateur Radio Service has multiple segments
of all of these bands, which allows it to be more
versatile and responsive to various communica-
tion needs than many of the public safety radio
systems.
King County, WA—December 1998—A large
metropolitan hospital suffered a failure of a
co-generation electrical system. A routine test
