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A comprehensive Training Approach for Biomedical Engineers
in Intensive Medicine and Operation Room Technology
B. SPYROPOULOS, M. BOTSIVALY, A. TZAVARAS, K. KOUTSOURAKIS
Medical Instrumentation Technology Department
Technological Educational Institution of Athens
12210, Egaleo, Athens
GREECE
http://www.bmtl.bme.teiath.gr
Abstract: - The purpose of this paper is to review 18 years (1987-2005) of experience in training young Biomedical
Engineers in Intensive Care Unit (ICU) and Operation Room (OR) Technologies. This encountering has resulted in the
gradual formation of a comprehensive training package that includes lectures and laboratory practicals, supported by both,
traditional and on-line digital means, such as lecture-notes, slides, videos, demos and equipment simulations. Further, this
course is maintained up to date by numerous research and development activities that offer partially feed back to the
course and enrich its contents with custom developed devices, methods and application software. In this paper are
presented, first, the structure and the components of this course, and second, the most important custom developed
novelties, which have been integrated in the Intensive Medicine and Operation Room Technology laboratory-practicals.
Key-Words: - Intensive Medicine Technology, Operation Room Technology, Emergency medicine Technology,
Biomedical Engineering Training
1 Introduction
Surgery, Emergency Medicine and Intensive Medicine
are closely interrelated and they are sharing common
Technology.
Therefore,
concerning
Biomedical
Engineering Training, it is methodologically implied to
approach Surgery, Emergency Medicine and Intensive
Medicine Technology as whole. However, it is very
helpful, to classify the equipment and the methods
applied, into three major functional areas. First,
technology of the in vivo monitoring of vital functions and
signals, second, technology supporting, substituting or
artificially restoring vital functions, and third, in vitro
diagnostics technology supporting Surgery, Emergency
Medicine and Intensive Medicine.
Obviously, Medical Imaging technology is also
employed in Surgery, in Emergency Medicine and in
Intensive Medicine. However, Medical Imaging
technology is usually universally applied within the
Hospital, and constitutes itself and extended area that
should be educationally approached as an independent
subject matter.
2 The Course structure
The course is divided into two parts, first a series of
theoretical lectures, given twice a week (4h/week) and,
second, a series of weekly 2h laboratory practicals, in 1520 participants groups. The duration of the course is 12-13
weeks/semester, and is offered in the seventh semester of
the eight-semester B.Sc.-Course in Biomedical
Engineering of the Medical Instrumentation Technology
Department, of the Technological Education Institute of
Athens.
This comprehensive training package is supported by
both, traditional and on-line digital means, such as lecturenotes, slides, videos, demos and equipment simulations.
2.1 Monitoring of vital functions.
Bio-electrical signals and non-electrical bio-signals are the
main information sources for the patient monitoring.
A typical ICU bedside monitor is the starting device for
the laboratory student training, and includes means for the
monitoring of ECG, Arterial Pressure, and Temperature.
Additional parameters such as EEG, EMG etc. are studied
by employing additional hardware or digital means. A
series of signal simulators serve as signal sources. pO2,
pCO2 are monitored by an additional Capnography device,
employing, first, an IR-spectroscopy unit for the pCO2
determination and, second, a Clark electrode for the pO2
measurement. A special hydraulic pressure simulator
allows for the invasive arterial pressure measurement, in
laboratory conditions, as well as, the monitor calibration,
for various pressure and cardiac frequency values.
Additional monitoring training occurs by employing a
neonatal care unit. Beyond the students’ acquaintance to
the technical details of the structure and the function of the
unit, skin and environment temperatures monitoring and
alarm means are also extensively studied.
The interaction between equipment producing extremely
high intensity electromagnetic fields, such as
electrosurgery and hyperthermia equipment, with the
monitoring devices, in operating room or elsewhere, is
also examined. After the detailed description of the said
devices, these are employed on phantom patients, such as
water phantoms or citrus fruits and both the results, first
on the objects, and, second, on the near installed monitors
are registered. Further, frequency and amplitude of the
produced fields are recorded, by employing a digital
oscilloscope, and the thermal energy deposited on dummy
loads is also measured. Finally, three different loopdetectors are employed in order to determine the energy
density, the magnetic field intensity ant the real
electromotive force induced on them. Thus, both, the
intended electromagnetic energy transfer to the patient, as
well as, the side effects of electromagnetic incompatibility
between medical devices, are studied in depth.
This part of the course is consuming approximately 40
% of the time in theory and laboratory practice.
2.2 Supporting vital functions.
Anaesthesia machines are vital to the practice of
anaesthesia. Current anaesthesia systems are being
developed with a number of alarm systems (manometers,
O2 flow, pO2 & pN2O in breathing circuit, IR-spectrometer
or mass-spectrometer anaesthesia agent detectors etc.) and
attachments. The physical characteristics of liquid/vapours
and gases, as well as, the temperature are especially
important in flow meter and vaporiser design. Ventilators
for anaesthesia have become an integral component of the
modern anaesthesia machine and allow ventilation, arterial
carbon dioxide control and compensation of changes in
lung compliance, during operation. Ventilators can be
divided into pressure-limited and volume-limited. An
anesthesia machine, three different ventilators, vaporizers
and other accessories constitute the basis for student
training.
Sudden cardiac death resulting from malignant
ventricular tachycardia (VT)
or from ventricular
fibrillation (VF) is one of the most common death modes.
Early defibrillation is the key to achieve a satisfactory
survival rate from cardiac arrest and automatic
defibrillators (AD) and ECG monitoring systems attempt
to reduce delays in differentiating shockable from nonshockable cardiac rhythms, using automatic detection
algorithms. The general medical consensus is that the
only cardiac rhythms that should be shocked are VF and
VT that causes the patient to be pulseless and unconscious
Analysis of arrhythmia signals can be made either in the
frequency or in the time domain and numerous methods
are published for both groups. Although many of the
published methods derived quite good results, most of
them were applied to rather limited databases, which in
many case were constructed for the particular application
and there is clearly room for further development. A
defibrillator, a special tester and various simulators and
several signal databases constitute the technical basis for
students’ training in Defibrillation.
This part of the course is consuming approximately 30
% of the time in theory and laboratory practice.
2.3 In vitro diagnostics support of ICU/OR.
Spectrophotometry is the major analytical method and
includes also Fluorometry, Flame Photometry, Plasma
Emission Spectrophotometry, and Atomic Absorption
Spectrophotometry and the corresponding automatic
Analyzers. The students are trained in typical VIS and IR
spectrophotometry, including also dry chemistry
employment.
Electrochemical methods include pH-meters, Ion
Selective Electrodes, Conductivity Measuring Systems
and Blood Gas Analyzers. Ion or dissolved gas
concentration are determined, by measuring the variation
of the corresponding output voltage or current, caused
each time to suitable electrochemical transducers, such as
electrodes outfitted with appropriate membranes. Various
electrodes are demonstrated to the students.
Separation techniques include several types of Gas,
Liquid and Thin Layer Chromatography, and
Electrophoretic Techniques. Main task is the separation of
mixtures of proteins or other substances and the
determination of the concentration of each component.
Separation is achieved by forcing the mixture to flow
through or run upon a solid or liquid phase and by taking
advantage of the different speed each component develops
during the procedure, because of the different size,
ionization, chemical affinity, electrical motility etc. of the
molecules or ions that constitute each component. The
students are trained practically in Electrophoresis and GC.
Immunoassays are procedures that rely on the use of
antibodies as “specific” binding reagents. These assays are
used to quantify or determine the presence of therapeutic
drugs, numerous biologic substances, infectious agents
etc. The principle of these assays is that a specific
reversible binding between an antigen and its
corresponding antibody will take place and that this
interaction will form a complex that can be differentiated
from bound or “free” ligand. To measure this interaction
or complex formation, various labels have been covalently
coupled to ligands, allowing for the detection and
quantification of the molecule of interest. As labels
radionuclides (RIA, IRMA), enzymes (ELISA, IEMA),
luminescent (LIA) or fluorescent (PFIA) compounds are
used. An adapted ELISA assay is demonstrated.
Hematology includes, beyond blood biochemistry, that
is covered by the above described methods and equipment,
cell counting and classification and coagulation chemistry.
Hematology Analyzers are based either i) on the Coulter
Principle i.e. the haematocytes are suspended in isotonic
NaCl solution and are counted by means of a measurement
of electrical resistance of the suspension or ii) on the
scattering of a LASER-beam on the flowing cell sample.
Flow Cytometers are based on LASER excitation using
crossed cylindrical to focus the beam as a sheet of light
through which fluorochrome tagged cells pass single file
for analysis. Microscopy is still an important
complementary method in Hematology, applied on any
case of doubt, concerning the results of automated
methods. A Coulter counter and a dilutor form the first
corresponding practical, and two microscopy working
places, equipped with digital cameras are also employed
for students’ training.
Coagulometers determine parameters such as Partial
Thrombin Time (PTT), Prothrombin Time (PT) etc. which
reflect the coagulation status of a patient by estimating
manually, photometrically, mechanically or magnetically
the time needed for clot formation. A
This part of the course is consuming approximately 30
% of the time in theory and laboratory practice.
3 Research and Development activity
supporting the Course
The course is maintained up to date by numerous research
and development activities, that offer partially feed back
to the course and enrich its contents with custom
developed devices, methods and application software. The
most important custom developed novelties, which have
been integrated in the Intensive Medicine and Operation
Room Technology laboratory-practicals, follow:
3.1 Arterial Pressure overshoots correction.
A system for the transfer line overshoot correction
employing a Fourier transformation [1] based restoration
of the distorted pressure waveform was developed, using
stored reference experimental data, obtained under
simulated clinical conditions, provided by a suitable
custom-made pressure generator. The experimentally
estimated MTF for several catheter and transfer lines
types, allows for correction for various arterial pressure
and heart rate values.
3.2 ECG waveforms classification.
We have developed Case-based Reasoning procedures used
for the evaluation of in vivo acquired ECG. The acquired
curve forms each time [2],[3] a “diagnostic vector" dj = dj
(a1j, a2j,...,akj) including these k diagnosis-relevant
information items akj of the j-th patient. This vector is
compared to a set of i diagnostic vectors Di = Di (a1i,
a2i,...,aki), i = 1,2,...,m, which correspond to already
evaluated by the medical expert cases and constitute a
continuously expandable reference knowledge base. These
vectors are correlated to certain heart failures as
Tachycardia, Heart-blocks etc. related to ECG-patterns.
By defining an appropriate comparison metric M, for the
n-th patient, a diagnostic proposal is displayed by the
system, by appointing to that case, the proposal attached
to the vector Di that minimizes the metric M (djDi),i=1,2,...,k.
3.3 Respiratory rate monitoring.
An aacquisition module including A/D converting
interfaces [5], has been developed, allowing for
respiratory rate monitoring. A thermal conductivity
variation detector, such as a thermo-couple, enabling
apnea monitoring of adult or neonatal ICU patients
acquires the respiration curve.
3.4 Fibrillation recognition.
A new technique [7],[9] for the Discrimination between
shockable and non-shockable Cardiac Rhythms was
developed based on the treatment of ECG signal as a bidirectional image and its comparison with two
conventional detection techniques based on Frequency and
Time Domain signal processing. In this new technique
discrimination between shockable and non-shockable
rhythms is made possible by dividing the ECG image into
certain regions of interest (ROI) and measuring the density
of “filled” pixels in these ROI. Normal sinus rhythm has a
specific distribution of pixels across these regions,
whereas the corresponding distributions of VF and VT
rhythms are remarkably different. For the processing and
the classification of the measured data a commercially
available neural networks program was used. The image
processing approach together with the use of neural
networks lead to considerably good results, reaching an
overall sensitivity of 100% and specificity of 95%. This
method proved to be very fast in the classification of the
unknown images and its results are comparable and some
times better with the ones obtained by the conventional
detection techniques.
3.5 Mobile Web-fitting Monitoring System.
Setting-up a Monitoring System outside an Intensive Care
Unit or even a Hospital, is often necessary or at least
desirable. Therefore, a portable, multipurpose, quasi realtime, and fitting to the Internet Patient Monitoring System
was developed [6], [8]. The system is composed of two
PCs, equipped with data acquisition and A/D-converter
boards, bio-signal preamplifiers, 2 Mbps wireless
communication PCMCIA-Cards, and 56 K modems.
Custom-made software is used for the formation and the
handling of a Biosignal Knowledge Base. Variable length
records of ECG, EEG and Respiration Rate, detected
through the temperature variations, induced on a tailormade thermo-couple sensor, can be acquired repeatedly
and can appear directly on a proximal PC- display, or be
transmitted through the wireless network to a distal PC,
and be posted to a server. Three data-sets were used to
check the system, the first consisting of 100, 4 sec long
records, generated by an ECG-simulator, combined to the
data acquisition system, using a 250 Hz sampling
frequency, the CSE multi-lead database, which includes
250, 10 sec long ECG records, and a set of 25 EEG and
Respiration Rate records.
3.6 Anesthesia agents monitoring.
A gas chromatographic method using a frequency
modulated ECD has been used for the Nitrous Oxide,
Halothane and Isofluorane trace analysis in air and the
verification of vaporiser calibration. A Mass Spectrometer
(1-200 AMU) has also been used as a reference method
for the determination of the Halothane and Isofluorane
traces [4]. The sampling devices include a small mobile
rotation pump, inflating nylon bags, 60 ml syringes,
balloons etc. Two calibration methods have been
developed. First, a static method employing a 25 l gas
exicator into which liquid Halothane or Isofluorane is
introduced, by using an Eppendorf micropipette and
isothermally vaporised, and second, a dynamic method
employing N2O, N2, O2 etc. gas cylinders equipped with
flown-meters allowing the formation of variable partial
pressure mixtures. The method is linear for Halothane and
Isofluorane in the critical range 0 - 100 ppm (v/v), since
for N2O the method is not linear in the critical range 0 500 ppm (v/v), and a calibration curve is needed. The
sensitivity of the method is about 1 ppm (v/v) for
Halothane and Isofluorane and about 10 ppm (v/v) for
N2O.
Management Advisor were preliminary compared to
published data, based on widely accepted knowledge on
respiratory control theory, in order to investigate the trend
of our system’s output. Changing selected physiological
input parameters, while maintaining all the other
parameters constant, allowed for the testing of the
system’s performance, which was always found to be
acceptable.
3.9 Properties of Surgical Sutures.
Important mechanical properties, such as the size, the
tensile strength and the knot tensile strength, of various
types of commonly employed, both, mono-filament and
multi-filament, surgical sutures, were investigated, and the
manufacturers’ specifications were experimentally
verified [13]. The mean length of the examined sutures
was equal to the declared on the packing within 0.7 %, and
no significant sample length dependent variation was
recorded. The mean breaking strength of some indicative
of the numerous suture types tested was also determined.
Tensile strength depends on sutures actual mean diameter,
and exhibits significantly lower reproducibility, when
measured on knotted sutures. The mechanical behavior of
all suture types tested was predictable, and conforms
adequately to the specifications given by the
manufacturer.
3.7 Anesthesia depth monitoring.
A Signal Acquisition Module [3] enables in the Operating
Room EEG-assisted anaesthesia monitoring based on the
evaluation of the power spectrum of an intra-operative
EEG. If V0(t) is the OR patient’s EEG-waveform before
the anaesthesia agent administration and Vá(t+ô) the
corresponding waveform at the time ô after the
anaesthesia agent administration, then, if f01, f02,..., f0n and
F01, F02,..., F0n are the frequencies and a01, a02,..., a0n and
A01, A02,..., A0n the amplitudes of the corresponding power
spectra, we define as anaesthesia depth index (ADI)
following ratio:
ADI =
A 01F 01 + A 02F02 + ... + A 0nF0n
_________________________
a 01f01 + a 02f02 + ... + a 0n f0n
3.8 Ventilation settings optimization.
A Fuzzy Logic based Ventilation Management algorithm
was developed, supporting the control of mechanical
ventilator tidal volume and frequency settings. The Fuzzy
Logic algorithm utilizes routinely acquired physiological
parameters and produces an advice for the required
changes in ventilator settings, according to the patient
needs. Capnography, Oxygen Saturation, Cardiac Output,
Body Temperature, Airways Resistance and Compliance
data, as well as, demographic patient data such as Height,
Age, Weight and Sex were the input-data for the fuzzy
algorithm. The results of the developed Ventilator
3.10 On-line Blood-Bank management.
We attempted to design [12] and partially implement an
on-line regional Blood Bank network administration and
operational cost-monitoring model. The developed model
comprises of following functional modules. First, A
typical Blood Bank administration module, including
documentation and management of all the routine
functions, such as Volunteer Donors Recruitment and
Incentives, Blood Donation, in site Transfusion, Blood
Processing and Conservation, Blood Serology, screening
for Infectious Diseases, Hematology Laboratory related to
Transfusion Medicine demands, and screening for
Abnormal Hemoglobin. Second, a data-base management
system that enables high-speed access to and processing of
data related to reagents, consumables, disposable and
other components of functional cost, financial and
administrative figures, safety and quality control statistics,
and information concerning manufacturers and local
representations. Third, a Patient, Procedure and in vitro
Laboratory Test Classification System, outfitted with a set
of Cost Calculation Algorithms that allows for the rational
approximation of the overall expenditure, and the quasi
real-time on line Blood Bank operational cost monitoring.
Fourth, a secure password protected Internet-accessible
Dynamic Medical and Administrative Text and Image
Library that supports remote Regional Routine
Administration, as well as, Crisis and Disaster
management. Finally, an educational module, comprising
of means such as on-line lecture-slides, lecture notes,
digital video material, self-evaluation quizzes, and other
important information, developed or made available, to
cover important subjects of Transfusion Medicine. The
system introduces a virtual networked Hospital Blood
Bank environment that promotes efficient administration,
facilitates realistic financial compensation of the involved
Units, by the Ministry of Health, and enables training and
decision making in the specific context of Transfusion
Medicine.
3.11 Supporting AMI treatment.
Software was developed [11], supporting “cardiac”
enzyme evaluation, during the implementation of typical
Acute Myocardial Infarction Treatment Guidelines, based
on Fuzzy-Logic rules. Reliable reported, average
diagnostic sensitivities, of commercially available
parameters, are taken into account, and they are
accordingly weighed in the employed algorithm. The
degree of certainty P, for the occurrence of an acute
myocardial infarction, is calculated, step by step, for each
enzyme concentration Ci, exceeding the “normal” interval
[Ci min, Ci max] by the following equation, where Pi1 and
Pi2 enzyme specific constants:
K1 Ci /(Ci max+Ci min) – Pi1,
Ci <Ci max
P ={
K2(Ci-Ci max)/( Cimax+ Cimin)+Pi2, Ci Cimax
For each new sample, the relative temporal location of the
corresponding value, and the increasing or decreasing
trend of the coterminous degree of certainty P, determines
the further procedure. Finally, the overall probability is
calculated, after consideration of the specificity weighing
factors. Temporal evolution graphs of the enzyme activity
of every treated patient can be displayed anytime.
Other relevant clinical patient data, including also
directly recorded or paper-strip scanned ECG waveforms,
can be stored in the system’s database. On demand, some
of these data can be also considered, appropriately
weighed, in the overall prediction algorithm.
3.12 EMI and Electrical Safety in the OR.
Electromagnetic Interference (EMI) from various sources
can cause medical monitoring equipment and other
hospital devices to malfunction, that can range from mere
inconvenience to serious problems. Comprehensive
induced Magnetic Field and Real Electromotive Force
measurements have been carried out and properly
documented in the form of an "on line risk distribution
map" covering all departments in the General District
Anti-Cancer Hospital of Piraeus "Metaxa" [10]. Over 500
devices have been tested for Electrical Safety. The
Enclosure Leakage Current measured, of 1.5% of the
tested equipment, exceeded the IEC 601.1 limit, and the
resistance measured during Earth Continuity Tests of 15%
of the tested equipment exceeded the limit. No further
deviations from the IEC 601.1 limits have been detected.
4 Conclusion
The quality of care available in the ICU and the OR is
related first and foremost to the quality of the nursing care
and to the clinical acumen of the medical staff. However,
without the necessary equipment and an appropriate
environmental design, the safety, efficiency, and economy
with which the patient care is delivered will be lessened.
The above described course attempts to contribute to the
fulfillment of the later necessary conditions, under real
world conditions, during the last 18 years.
Acknowledgement: Financial support for this work and its
dissemination efforts was provided by the project “Upgrading of
Undergraduate Curricula of Technological Educational
Institution of Athens”, APPS program - ΤΕΙ of Athens, financed
by the Greek Ministry of Education and the European Union:
Greek Operational Programme for Education and Initial
Vocational
Training-O.P.
Education
Action:
2.2.2.
“Reformation of Undergraduate Studies Programs ”.
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