Biomedical Engineering Reference
In-Depth Information
observer. The technician, Nitze, constructed the first
truly practical endoscope. These instruments were used
for rectoscopy and cystoscopy. From that time onward,
the endoscopes have been continuously improved.
Nowadays, endoscopes and laparoscopes furnished with
flexible fiber optics or with cylindrically shaped lens
systems (the Hopkins-optic) are in use. With the help of
these modern devices, minimally invasive diagnostics
and surgery progressed rapidly. The diagnosis and ther-
apy of the digestive system, rectum, bladder, respiratory
tract, joints, and abdominal cavity can be carried out with
less trauma than with the conventional methods, which
typically required large incisions. Introduction of cathe-
ters, biopsy forceps, electrocoagulation instruments, and
lasers can be done with devices evolved from endoscope.
pulse, respiration, ECG, blood pressure, and blood sugar
level. This, to some extent, is the vision of the future; but
considering the pace of development in the last few de-
cades, one may safely say that this is not the illusion of
the far future. The science of robotics is enabling ma-
chines to replace some of the operations of the surgeon.
Will the human ever be completely replaced by machines?
Understanding the physical world
In the previous paragraphs the development of medical
device technology was introduced in a nutshell, through
examples. These brief episodes demonstrate well that, in
the course of development, combination and interaction
of different scientific disciplines have played an impor-
tant role. Formerly, usually one person facilitated this
interaction. In the time of Hippocrates, for example,
scientifically oriented people had a wide interest and
philosophical inclination. Because of the lesser quantity
of the available scientific knowledge at that time, sur-
veying it was easier for one person. This helped to de-
velop those statements and discoveries that demanded
multidisciplinary knowledge from the inventor. Such was
the situation until the last few centuries.
Taking a great leap in historical terms to the Enlight-
enment, the progress in understanding the law's of nature
was rapid and substantial. The seventeenth century is
considered to have been the century of geniuses, and the
eighteenth century is considered to have been the period
of brightness and the mind. The Bernoulli brothers
(Jacob and Johann), Herman von Helmholtz, Gottfried
Wilhelm Leibnitz, and Isaac Newton towered above the
geniuses. Newton, in his
Principia,
who also built upon
the observations of Galileo, Copernicus, and their con-
temporaries, gave the best description of mechanics of
their time. With the infinitesimal calculus, and with
Newton's mechanics as a basis, Leonhard Euler, a Swiss
mathematician, described the movement of solid bodies
and developed the basic equations of hydrodynamics.
Galvani and Volta laid the foundation for knowledge of
contemporary electricity.
During the eighteenth century and beyond, the bulk
of work went into observation and understanding natural
phenomena, the qualitative recognition of the laws of
nature, and their formulation in statements and equa-
tions. The growing amount of knowledge and the im-
mersion into the details necessarily steered scientists
toward specialization. The epoch of polymaths began to
fade away. Due to the prompting effect of the industrial
revolution, demand on practical application of sciences
strengthened. A technical revolution followed the sci-
entific revolution. Application of discoveries accelerated.
The number of inventions grew. The steam engine and
the principle of the dynamo, followed by the general use
Laboratory devices
Together with the development of biology, medical sci-
ence, and measurement techniques in chemistry and
physics, the variety of laboratory devices has increased
enormously. With the help of the modern laboratory
automatons, the number of different measurements
done today is in the order of hundreds of millions per day.
Of course, this practice also raises the number of
companies that supply the reagents and disposables.
Surgical instruments
These instruments are usually not of concern to clinical
engineers. However, for the sake of completeness, they
should be mentioned. The number of surgical instruments
ranges in the thousands. Many of them are engineering
marvels, the products of cutting-edge fabrication tech-
nologies and advances in metallurgy and materials science.
Patient monitoring devices
for intensive therapy
Modern technology and engineering opened the door for
the application of individual equipment in systems. Two
good examples are the complex array of equipment in
the operating theater or the installations in the intensive
care units. Patient monitoring systems, respirators, de-
fibrillators and others constitute an integrated system. The
measurements of one device might affect the operating
parameters of the other. The harmonized functioning
of these devices has required the attentive presence and
intervention of the physician or intensive therapy nurse.
One ongoing development is the automation of pro-
cesses and the involvement of information technology.
The patient will become a part of a feedback loop, in
which the system automatically sets and maintains the
optimum parameters. Such parameters might include
