Biomedical Engineering Reference
In-Depth Information
''Small'' error and devastating
outcomes
such a discussion occurs much more frequently now in
pre-op meetings (as well as hospital board meetings)
throughout the world. Although, it is quite likely even
this focus has attenuated in the years since the tragedy.
The public and our peers will judge whether we apply
due diligence or whether our designs and projects are
impaired by something we should have known and
considered.
Duke University is blessed with some of the world's best
physicians and medical personnel. As a research institute,
it often receives some of the most challenging medical
cases, as was the previously mentioned case for Jesica
Santillan, a teenager in need of a heart transplant. Al-
though the surgeon in charge had an impeccable record
and the hospital is world renowned for such a surgery,
something went terribly wrong. The heart that was
transplanted was of a different blood type than that of
the patient. The heart was rejected, and even after an-
other heart was located and transplanted, Jesica died due
to the complications brought on by the initial rejection.
The logical question is how could something so vital and
crucial and so easy to know as blood type be overlooked?
It appears to be a systematic error. The system of checks
and balances failed. And, the professional, i.e., the sur-
geon, is ultimately responsible and primarily accountable
for this or any other failure on his watch.
What can we learn from the Santillan case? One lesson
is that a system is only as good as the rigor and vigilance
given to it. There is really no such thing as ''auto pilot''
when it comes to systems. Aristotle helps us here. He
contended that the whole is greater than the sum of its
parts. This is painfully true in many public health di-
sasters. Each person or group may be doing an adequate
or even superlative job, but there is no guarantee that
simply adding up each of the parts will lead to success.
The old adage that things ''fall through the cracks'' is
a vivid metaphor. The first mate may be doing a great job
in open waters, but may not be sufficiently trained in dire
straits when the captain is away from the bridge. A first
response team may be adequately trained for forest fires
(where water is a very good substance for firefighting),
but may not properly suited for a spill of an oxidizing
agent (where applying water can make matters consid-
erably more dangerous). Without someone with a ''global
view'' to oversee the whole response, the perfectly ade-
quate and even exemplary personnel may contribute to
the failure.
Systems are always needed and these systems must
be tested and inspected continuously. Every step in the
critical path that leads to failure is important. In fact, the
more seemingly ''mundane'' the task, the less likely
people are to think a lot about it. So, these small details
may be the largest areas of vulnerability. Like the but-
terfly effect in chaos theory, the chain of events or
critical path of one's decision will ultimately determine
whether it is a good one or a bad one. One must wonder
how many presurgery meetings before the Santillan case
had significant discussions on how to make sure that the
blood type is properly labeled. One can venture that
Technology, engineering,
and economics
Although engineers are a diverse lot, most are more than
a little utilitarian. They strive to provide the greatest
amount of goods and services to the greatest number
(however these terms are defined and constrained by the
design specifications). The National Academy of Engi-
neering recently declared that ''engineers and their in-
ventions and innovations have helped shape the changes
that have made our lives more productive and fruitful.''
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But what does it mean to become more fruitful? It must
be something beyond pure utilitarianism. To begin, we
can consider the economic implications.
Bioethics Question: Does biosystem engineering
ethics go beyond utility in defining what is ''right?''
Technology is the obvious indicator of biosystem engi-
neering. It is the ''workhorse'' that delivers on bio-
systematic designs. In economics, technology can be
considered a tool of empowerment, in that it empowers
producers to generate more output from given levels of
the two inputs, labor and capital. In this sense, as a cata-
lyst in chemistry is a substance that increases the rate
of reaction, technology is a catalyst for production of
output - as it increases the amount of output we get from
given inputs.
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Technology allows for the use of more
advanced capital, which results in better and faster ways
to create output. Producers are rendered more efficient,
as they are able to produce more output, given the same
amount of input. This results in greater profit, which
results in economic growth. For example, if we consider
the basic supply-demand model, we see that improve-
ments in technology cause the supply curve to shift out to
the right, meaning that producers will create more
output for any given price (
Figure 8.1-3
). This raises
equilibrium output and lowers equilibrium price. Equi-
librium, in this case, is used to refer to the price level at
which the aggregate supply curve (an upward sloping line
that illustrates how much producers would be willing to
supply at any given price) crosses the aggregate demand
curve (the downward sloping line that shows how much
of a good consumers would demand at any given price).
This price level is called the ''equilibrium'' price because
