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Journal for Hygiene in Hospitals and Medical Practice • Edition November 2007
aseptica
www.aseptica.com
TITLE TOPIC
Clostridium difficile –
Pathogen increasingly
common worldwide
Clostridium difficile –
Pathogen increasingly
common worldwide
English Edition
Editorial
aseptica English Edition 20072
Content
The significance of washing pressure
measurements in WDs S. 3
»It all comes out in the wash!« S. 5
Validation with regard to washer-
disinfectors (WDs) from the user’s
point of view S. 8
Clostridium difficile – Another
significant nosocomial pathogen S. 11
Restructuring CSSD –
where are we going? S. 14
The International FORUM Medical
Devices and Processes
Berlin: 2006/2007:
A Review and a Preview S. 16
Checking instrument cleaning by
reflectometric measurement S. 18
Evaluation of a fully automated
decontamination processes for prion
decontamination using cell culture
and chemiluminescence tests for
surface-bound prions S. 20
Resistances from the Intestine S. 22
Dear Readers,
what was it we wanted?
The 2nd International Edition of aseptica is reaching out for the world!
This doesn’t mean to say we are "teaching the deaf", but fact is, that
there are many curious people out there, wondering how we cope with
sterile processing and associated products (not to say problems). As we
are faced with a world population that is growing and aging, a natural
growth of the international health care sectors is to be expected (cf. our
Market Study in last year's international edition).
Small but highly productive nations like Germany might have their share – if
we are there! There is an open invitation to
participate in national markets worldwide. My resumee of our visitations of
several countries within the framework of the
7th International FORUM
Medical Devices and Processes: In Mexico,
the 4th Panamerican
Congress on Sterilisation had 1200 visitors. A huge medical fair in
Zhangzhou showed China and Chinese know-how at its best. In Russia,
Georgia, Armenia there is an enormous demand for surgical and endoscopic
equipment, apart from the rush for dental implantation. There is a wide
range of interests and questions concerning details like ‘Which disinfectant
do I use to what end?’ as well as gigantic projects, e.g. hospital rebuilding.
Are we ready to play a part in all of this? Is there anybody out there to
provide support? Who will answer questions on disinfectant use, manual
or automated cleaning and such, when there are so many doing the job?
Why data loggers if I have these nice indicators? The gap between the
daily routines and our wishful thinking might be huge, but the world is
jumping at us while we are busy discussing guidelines for regulations
(or vice versa). In order to parttake in the global development, we will have
to travel as far as Marco Polo once did and get to the places, where our
expertise is needed.
By the way: The label "Made in Germany" was introduced to discriminate
German products, which partially copied English originals. What was it we
wanted?
Thomas W. Fengler
xxx
aseptica English Edition 2007 3
Process validation for flexible endoscope
washer-disinfector appliances
F. Wille
Author
Dr. Frank Wille
Managing director
Geschäftsführer
HYBETA GmbH
Albrecht-Thaer-Str. 14
48147 Münster
Tel.: 0251/2851-150
A method for validating automatic
wash-disinfection processes for fle-
xible endoscopes was developed,
based on the standard prEN ISO
15883-4:2005. The aim was to make
the validation relevant to the prac-
tical situation and above all to make
it affordable, so that its acceptance
by users would be as great as possi-
ble. For a little over a year now the
process has been continuously furt-
her developed. It is acceptable to
both users as well as the monitoring
authorities. With the help of this
method, processes can be validated
from appliances already in use as
well as from new appliances.
According to § 4 paragraph 2 of the Medi-
cal Device Operator Ordinance (MDOO),
washing, disinfection and sterilisation of
medical products should be carried out
using validated processes. The requirements
of the MDOO are clear: all automatic pro-
cesses must be validated. In contrast, prac-
tical implementation is still very sluggish.
While validation of sterilisation processes is
already carried out ubiquitously, the valida-
tion of washing and disinfecting processes
is only slowly catching on. This applies
however, only to the reprocessing of ther-
mo-stable medical products. Process valida-
tion of chemo-thermal wash and disinfec-
tion processes for reprocessing of flexible
endoscopes has seldom been carried out up
to now.
The fundamental reason for this is the
lack of standardised principles and recom-
mendations from specialist bodies/associati-
ons. The requirements for washer-disinfector
appliances (WD) are laid down in the stan-
dard series DIN EN ISO 15883. Parts 1-3
were completed in December 2005 and have
been available since April 2006 in German.
Parts 4 and 5 are still at the draft stage.
Part 4 has been available as a second draft
since June 2005. It contains the require-
ments and test methods for WDs using
chemical disinfection for thermo-labile
endoscopes (WD-E). The draft standard
defines the appliance requirements and fit-
ments. In chapter 6 of the draft the various
tests are described and Appendix C defines
which tests should be carried out for opera-
tional tests and performance tests. Detailed
directions for carrying out validation are
omitted.
As well as the standards listed above,
there is a guideline for the validation and
routine monitoring of automatic
washing/disinfecting processes for thermo-
stable medical products (validation guideli-
ne) published by the DGKH (Deutsche
Gesellschaft für Krankenhaushygiene- Ger-
man Society for Hospital Hygiene), the
DGSV (Deutsche Gesellschaft für Sterilgut-
versorgung- German Society for Sterilisati-
on Services) and the AKI (Arbeitskreis
Instrumentenaufbereitung- Instrument
Reprocessing Working Group). This Gui-
deline contains concrete descriptions of
how process validation in WDs should be
carried out. For WD-E a guideline like this
is only in the planning stage. Based on the
standards, draft standards and the validati-
on guideline described above, the firm
HYBETA GmbH in cooperation with
Olympus, has developed a method for pro-
cess validation in WD-E, which fulfils the
legal requirements. More than 50 washer-
disinfector WD-E processes from various
manufacturers have already been validated
according to this method. The results were
checked by the various monitoring bodies
of several German federal states and accep-
ted without exception.
Validation
Before starting validation, the premises and
the organisational conditions should be
appraised. For appliances already in use, it
must be ensured that validation is possible.
In addition, these appliances require servicing
according to the manufacturers directions.
According to the validation guideline, the
actual validation consists in installation, ope-
rational and performance qualifications.
Installation qualification
The installation qualification (IQ) is carried
out according to the relevant checklist 4 of
the validation guideline. For the IQ, amongst
other things, the manufacturer, appliance type
and appliance number are recorded. Checks
are made to see that the appliance is correctly
connected and is in impeccable technical con-
dition. Also the relevant appliance documents
are checked for completeness.
Operational qualification
The operational qualification (OQ) also fol-
lows the validation guideline –checklists 5
and 6.
During the course of the OQ, amongst
other things, the reprocessing programmes
used are recorded and the appliance func-
tions (e.g. appliance malfunction message
system) are checked. For appliances able to
test the patency of tubes, there is not yet a
complete check of the malfunction message
system. At the moment no check is available
that is suitable for the practical situation.
The same applies to the leak tightness test-
here too, suitable test equipment is lacking.
xxx
aseptica English Edition 20074
As well as the points listed above, the per-
formance parameters of the appliance are
also measured, for example the cleaning
pressure, the volume of water run in and
the doses of the process chemicals. In addi-
tion thermometric tests in the wash cham-
ber are carried out, as laid down in the
standard DIN EN ISO 15883-1: 2006-04.
Performance qualification
After successfully carrying out the installati-
on and operational qualification, the perfor-
mance qualification (PQ) can be started.
This comprises tests on cleaning and disin-
fection performance. Here microbiological
tests on the final rinse water are also carried
out. For the performance qualification test,
models described in chapter 6.11.3 of the
standard prEN ISO 15883-4:2005 are used.
Test model
The test model consists of a 2m length of
PTFE tubing. According to the draft stan-
dard two test models with different internal
diameters are required. The models should
have an internal diameter of one and four
millimetres respectively. Countless tests have
shown that the requirements for cleaning
and disinfection are greater for narrower
tubes. To reduce validation costs, only the
model with a one millimetre diameter is
used. Three test pieces made of 20cm lengt-
hs of tubing are integrated into the model.
The first test piece is contaminated with a
suspension of Enterococcus; the second with
a Pseudomonas aeruginosa biofilm. The
third test piece tests cleaning performance
using a test contamination of proteins, fats
and polysaccharides. The manufacture of
tubing models is carried out according to a
quality-controlled and standardised method.
When the process is finished, the test
models are taken out and first of all checked
visually for cleanliness. Then the three pie-
ces of tubing are processed further in the
laboratory. The testing of the chemothermal
disinfection performance is carried out by
determining the microbiological reduction
of the test germs used. For tube length 3
(test contamination) residual protein deter-
mination using the Biuret method is made.
Test instruments
As well as testing the tube models, the clea-
ning performance for other additional instru-
ments was recorded. During everyday use, in
addition to flexible endoscopes other instru-
ments are cleaned and disinfected in the
WD-E at the same time. Testing is carried
out as described in the validation guideline,
using Crile haemostatic clamps. For the test
contamination, heparinised sheep’s blood
rendered able to coagulate with protamine
sulphate, is used. These test instruments are
also removed at the end of the process and
checked visually for cleanliness.. Finally in
addition, residual protein determination is
carried out using the Biuret method. In order
to test the cleaning of endoscope attachments
in the attachment trolley, a test body is used
that simulates a hollow instrument. It can be
adapted to the connection on the attachment
trolley using a Luer lock connector. Inside
the test body is a stainless steel plate conta-
minated with sheep’s blood, according to the
validation guideline.
Measurements
During the tests, the relevant process para-
meters such as temperature, cleaning pres-
sure, volume of water, time and dosage of
process chemicals are recorded indepen-
dently of the appliance documentation, to
compare them with the appliance recor-
dings. Because of this, a parametric release
is made possible for routine operation.
Should the appliance not have a suitable
recording system, then the necessary routi-
ne control checks are carried out as part of
the validation report. The concentration of
disinfectant is calculated from the volume
of cleaning solution and the dosage of
disinfectant. For this the dosage of disinfec-
tant is established gravimetrically and the
cleaning solution volume is determined
using a calibrated water meter. The concen-
tration, temperature and holding time are
stipulated by the disinfectant manufacturer.
For this reason, the temperature and hol-
ding time are monitored during the entire
disinfecting stage, using a data logger. In
addition the temperature distribution in
the wash chamber is tested. The temperatu-
re and time measurements are made using
calibrated data loggers from Ebro. To ensu-
re the reproducibility of the processes, at
least three consecutive run-throughs are
tested. On each load carrier a tube model is
connected to the connection for endosco-
pes, so that 6 models in total are tested.
When testing the attachment trolley, the
test bodies are arranged so that the partsFigure 1: tube model
achtung - noch deutschebezeichnung
Figure 2: tube model on load carrier
xxx
aseptica English Edition 2007 5
most difficult to reach are recorded.
Validation is regarded as successful if all
the test cycles show a sufficient cleaning
and disinfection performance and if the
Figure 3: measurement of the dosage Figure 4: connected test equipment
recorded process parameters lie within the
tolerances defined by the manufacturers.
To conclude, the results are documented
in a detailed and comprehensive validation
xxx
The preparation stages of cleaning
and disinfection of medical devices
in the Central Sterile Supply Depart-
ment (CSSD) are the focus of consi-
derations for personal and patient
safety. Information published by the
regulatory authorities indicates defi-
ciencies in clinical quality manage-
ment and instrument management,
but in particular in process validati-
on of the preparation of medical
devices which can be explained by
economic constraints and a lack of
knowledge. If committed and quali-
fied hospital staff are on site they
can, after appropriate training,
undertake the performance qualifica-
tion for cleaning and disinfection
equipment (CDE) using a set of
equipment. This method, set out by
the German Society for Hygiene in
Hospitals (DGKH), not only saves
costs, it also increases the quality
Validation in a Team – Process Validation for Cleaning and
Disinfection Equipment in the CSSD [Central Sterile Supply
Department] by qualified hospital staff
B. Schlappler-Scheele, S. Krüger, N. O. Hübner
of preparation and reduces civil law
and liability risks.
The Problem
High quality preparation of medical devices
is becoming increasingly important. The
requirements placed on the professional
qualifications of those working in the
CSSD contribute to this [1], as does the
realisation that device management in a
hospital accounts for a significant proporti-
on of the budget alongside staffing costs.
Innovations in medical technology leave
their mark in the complex instrument geo-
metry with all the resultant problems for
preparation. In all cases the legislator
demands a preparation result »which does
not endanger the safety or health of pati-
ents, users or third parties« [2]. Only those
who take into account the stipulations of
the RKI [Robert Koch-Institut] for hygiene
when preparing medical devices are on safe
ground in terms of legal implications. This
Author
Dr. med. Bernhard Schappler-Scheele
Groß-Buchholzer Kirchweg 39
30655 Hannover
E-Mail: schappler-scheele@htp-tel.de
Sigrid Krüger, Leitung der Sektion
Reinigung und Desinfektion
Deutsche Gesellschaft für Kranken-
haushygiene (DGKH)
Minneweg 22
21720 Grünendeich
E-Mail: sigrid-krueger@t-online.de
Dr. med. Nils-Olaf Hübner
Beauftragter der DGKH
Ernst-Moritz-Arndt-Universität Greifswald
Institut für Hygiene und Umweltmedizin
Walter-Rathenau-Straße 49a
17487 Greifswald
E-Mail: huebner@uni-greifswald.de
report. The validation report also includes
recommendations-relevant to the particu-
lar appliance equipment- for the carrying
out of routine monitoring.
Summary
During the course of tests so far, some
appliances have showed insufficient disin-
fection performance. These results always
correlated with deviations in the determi-
ned process parameters. This shows how
important the validation is in combination
with parametric release- for patients’ and
employees’ safety. ■
xxx
aseptica English Edition 20076
and hospitals can, however, lead to success,
despite the complex material [11].
The validation guidelines produced by
the DGKH, DGSV [German Society for
Sterile Supply] and AKI [Instrument Prepa-
ration Working Group] for C+D processes
for thermostable medical devices set out in
the annex the »Qualifications of the valida-
tor – requirements for the qualifications of
persons undertaking validation« [12]. Loo-
king at the evidence of training and valida-
tion files for external validators is sufficient
to enable technical experts to realise that
the same could be achieved at least as suc-
cessfully by their own personnel following
training in a team consisting of three spe-
cialist disciplines (technician, hygiene spe-
cialist, sterilisation assistant).
Manufacturers of cleaning and disinfec-
tion equipment often perform process vali-
dation for CDE from their own product
range and therefore have a great deal of
know-how when it comes to the use of
CDE in practice. They therefore represent a
potential know-how resource which should
always be involved, in the interests of high
quality medical device preparation.
The Solution
After inspecting 38 hospitals (35 of which
did not have validated C+D processes) it
was decided to propose that the quality
standard of the DGKH, DGSV and AKI
guidelines be met by means of a validation
team. With pressure from the authorities
owing to the prospect of huge cost savings,
hospital managers were quickly recruited
for a pilot project. Seven hospitals in the
Hanover area took part in the study, inclu-
ding the Medizinische Hochschule Hanno-
ver (Hanover Medical College, MHH).
The aim was to equip members of hospital
staff with qualifications and knowledge
such that the performance qualification for
CDE would conform to the guidelines pro-
duced by the various associations.
In December 2006 the DGKH took on
the overall leadership of the pilot project.
The first hospital to successfully complete
the final examination before the head of
the Cleaning and Disinfection Section from
the DGKH in the presence of the regula-
tory authority responsible was the team
from Hanover Medical College. The
Gewerbeaufsicht [inspectorate] deemed
Captions for figures:
Figure 1: Documentati-
on of hygiene, occupa-
tional health and
safety, quality and
instrument manage-
ment along with manu-
facturers’ information
and validation folders
at a CSSD.
is intrinsically linked to the need for full
and complete evidence demonstrating that
preparation was undertaken using suitable,
validated processes* [3].
In the field of validation of cleaning
and disinfection processes the so-called cur-
rent standard of technology is defined by
the national implementation of EC direc-
tives [4], European standards relating to the
various devices [5], guidelines [6] and an
abundance of technical-organisational
instructions [7, 8]. Many of those who
operate CSSDs find this body of legislation
so complex that they outsource the validati-
on of their preparation processes and there-
fore do not make use of their own know-
how in the area of preparation quality.
The fact that the preparation of medi-
cal devices in Germany is not necessarily
always performed in line with legal require-
ments and that not all the options are
exhausted is evidenced in information
published by the regulatory authorities [9,
10]. This is astonishing given that qualifica-
tions, commitment and a sense of responsi-
bility are often a given on site (see figure
1). Cooperation between the authorities
xxx
aseptica English Edition 2007 7
that the validation measures were perfor-
med in line with legal requirements.
To the point of demand-oriented routi-
ne validation in the CSSD this qualificati-
on plan for hospital personnel consists of
seven steps. These are:
step 1: forming the validation team;
step 2: training course;
step 3: validation set;
step 4: gaining practical experience on site;
step 5: final examination before the
DGKH;
step 6: certification by the DGKH;
step 7: routine validations.
Because detailed information on these steps
would go beyond the scope of the publicati-
on please refer to the information platform
for validation teams. Overviews, round-ups
and all the building blocks for your own
successful validation can be found at
www.validieren-im-team.de along with
contact addresses for training providers.
Step 1: Forming the validation team
The qualification requirements for persons
performing validations in C+D processes
are set out in the annex to the DGKH,
DGSV and AKI validation guidelines (see
above). This makes it almost essential to
form a team with one representative from
each of Technology, CSSD and Hygiene.
The area of responsibility of the Tech-
nology representative includes ensuring
that the basic technical requirements for
successful operation of the equipment are
met. The installation qualification (IQ)
and the operational qualification (OQ) for
the CDE and the quality of the process
media are all relevant here. The manufac-
turers are under an obligation here, with
the involvement of the hospital’s own tech-
nical staff. For collaboration in the team to
undertake performance qualification (PQ)
technical knowledge of the equipment is
necessary, along with knowledge of instru-
mentation and control technology for
CDE.
The »CSSD« team member is particu-
larly important. As the person responsible
for preparation processes in the CSSD this
team member knows the operating proce-
dures, operational conventions and instru-
ment management, thereby ensuring prac-
tical relevance. Because this team member
has day-to-day responsibility he/she should
lead the validation team and must have at
least Fachkunde 2 [Technical Qualification
2] in accordance with the Guidelines on
Technical Training Courses from the
DGSV-SGSV.
The specialist in hygiene forms the
team’s link to the legal framework, quality
management and hygiene management in
the hospital. His/her specialist training,
concluded with a state examination, should
ensure that the validation team acts in
accordance with legal requirements.
His/her involvement in the team again
takes into account the hygiene require-
ments and is helpful in developing prepa-
ration instructions and embedding these in
the hospital’s documentation system.
Once these three people have been
identified they can register with a course
provider who is registered with the DGKH
(see website) and obtain their qualification.
For quality assurance reasons the course
provider must register with the offices of
the DGKH.
Step 2: Training course
In just two working days the training cour-
se gives the team all the basic knowledge
needed to understand how to responsibly
undertake the performance qualification of
processes with solely thermal disinfection.
This includes, but is not limited to, know-
ledge of microbiology, law and standards,
the technology of equipment and procedu-
res, media supply, measuring systems and
methods to determine the cleaning effi-
ciency as well as documentation require-
ments. The focus is on learning the infor-
mation which is important in practice,
avoiding looking at the subject matter
from too specialised a scientific perspective.
Short practical exercises in determining
residual protein using the biuret/BCA
method are included even at this early sta-
ge. Temperature, pressure, pH value and
conductivity measurements using datalog-
gers, the relevant validation software and
the significance of the data obtained are all
covered in detail. After this the team is able
to undertake the validation of a perfor-
mance qualification of a CDE in theory,
they know the legal background and the
documentation requirements and are able
to assess the performance of the cleaning
and disinfection process and sources of
errors.
The course concludes with a final
examination based on a list of questions
compiled by the DGKH. The team solves
this exercise together because the questions
deal with various subjects. If the team is
successful each team member receives a so-
called Testat 1 [Certificate 1] from the
DGKH, which only relates to the individu-
al’s specialist discipline. For reasons of
workflow management and quality assuran-
ce, course providers must notify the
DGKH of any participants in the course
with a Testat.
Step 3: The validation set
It is not possible to perform process valida-
tion without the relevant equipment. As
for external validators, the team must be
able to continuously record the process
parameter temperature. It should also be
possible to measure the parameters pressu-
re, pH value and conductivity. Analysis
software makes documentation considerab-
ly easier and technically sophisticated soft-
ware is available. The test clamps and addi-
tional test specimens described in the
validation guidelines produced by the
various associations can be obtained easily
over the internet. This also applies to sets
or kits used to assess the performance of
the cleaning process in terms of determi-
ning the residual protein using the biu-
ret/BCA method. A complete list of the
equipment necessary for validation can be
found at www.validieren-im-team.de.
Equipment to enable continuous measure-
ment of pH values and conductivity is now
on the market and again improves the
assessment of CDE performance in run-
ning equipment cycles.
Because dataloggers can capture rele-
vant CDE process parameters as often as
every second and the validation software
can represent these on-screen by curves of
various colours the result is a visual repre-
sentation of the relevant processes against
time. Malfunctions in the equipment, loa-
ding errors and areas which are not cleaned
as a result of these are immediately appa-
rent, as is any drop below the necessary A0
xxx
aseptica English Edition 20078
protocol, preparing the validation folder
and having a team discussion. With a view
to the success of the team it is sensible to
start including the content of the DGKH
final examination during the practical stage
(please refer to the website). As a primary
benefit the practical stage also includes
training and instruction in using the
equipment. After this the team should be
ready to register for the final examination.
To conclude the practical experience stage
the external trainer awards the members of
the team DGKH Testat 2.
Step 5: The final examination
In this stage the team performs a standard
performance qualification with thermal
disinfection using CDE in front of a repre-
sentative from the Cleaning and Disinfec-
tion Section of the DGKH, thereby sho-
wing their ability. The CSSD member of
the team leads the demonstration in accor-
dance with his/her responsibility for the
preparation of medical devices. The con-
tent of the examination includes, for exam-
ple, the selection of reference loading, test
instruments, using the dataloggers, stan-
dard positioning of the test specimens
along with monitoring, analysis and docu-
mentation of the parameters obtained.
Finally there is a team discussion in which
the reasons for the choices made are pre-
sented in order to examine the team’s
understanding of the process.
In addition, the validation folder is
reviewed. At this stage this folder should
contain the protocols for the sampling and
maintenance measures, the team’s qualifica-
tion certificates [Testate], calibration certi-
ficates for the dataloggers, collected infor-
mation on the measuring system used and
all the documentation of the process para-
meters obtained together with an asses-
sment of these.
Step 6: Certification
The certificate awarded by the DGKH
recognises the team’s ability to perform
validations using CDE with the restriction
that it is only valid for performance quali-
fication and for processes using thermal
disinfection. This confirms at a high level
that the measurements taken by the valida-
tion team are correct in terms of methodo-
logy, complete and reproducible. On the
basis of these high quality findings, a con-
clusive microbiological-medical risk asses-
sment and interpretation by the Specialist in
Hygiene are also possible. The certificate is
related to each individual in the team but is
awarded as an integrated award covering all
three disciplines. Because it does not contain
any local limitation team members can be
recruited at will if a team member leaves.
The registration process with the DGKH’s
offices validates selective top-up training for
new team members. Because the manage-
ment of the team is linked to the CSSD spe-
cialist, the main know-how remains within
the individual hospital in accordance with
the responsibility.
In order for the team to have freedom
from instructions an appropriate letter […].
Step 7: Revalidation and
Routine Monitoring
The validation team is now familiar with
the process. They validate the cleaning and
disinfection equipment processes whenever
any parameters change in the preparation
processes. Routine monitoring is now
easier because the hospital has the neces-
sary measuring equipment. When perfor-
med periodically, systematically or just in
case this strengthens the assumption that
preparation is being performed correctly.
The understanding of the functions of the
equipment and the processes increases and
leads to regulatory measures whenever this
is seen to be needed.
Summary
The German Society for Hygiene in Hos-
pitals (DGKH) is supporting a model
which has already successfully completed
the pilot phase. Because of the nationwide
significance, complete drafts of all the
DGKH documents are already available on
the internet at www.validieren-im-team.de
in the form of an information platform for
future validation teams. The seven steps
outlined represent an appropriate method
for validating CDE processes in a CSSD in
a way which conforms with the standards
within the legal framework. It allows hospi-
tal staff to cut costs, increase the quality of
preparation and reduce the risk of infec-
tion. ■
values. Improved loading configurations or
optimised process management can be eva-
luated during operation to make sure the
operation is worthwhile.
As a matter of principle every hospital
with a validation team should have a com-
plete validation set at all times so that re-
validation is possible at short notice, for
example if new instruments are introduced.
This also supports regular routine monito-
ring in terms of organisational and techni-
cal factors. Equipment sets which are loca-
ted in associated hospitals are
counterproductive here.
Dataloggers and validation software are
expensive initially but this is quickly and
certainly balanced by the cost savings. Not
complying with legal regulations can
quickly become more expensive if it is not
possible to demonstrate evidence of valida-
ted preparation during liability proceedings
or if requirements stipulated by the regula-
tory authorities have to be fulfilled. For
smaller hospitals it can be feasible and
expedient to join together to form so-cal-
led »machine pools«. Buying equipment in
bulk can also give significant savings with
each hospital involved still receiving its
own set with a full guarantee. It is neces-
sary for those responsible for purchasing to
come to an agreement in order for this to
happen, and this could be organised by the
Hospital Federations [Krankenhausgesell-
schaften] in the individual German states.
Step 4: Gaining practical experience
The validation team must »grasp« their
process, i.e. in a very literal sense the team
must have picked up the equipment set in
their own hospital. External validators regi-
stered with the DGKH can help here and
can be found on the internet. Before trai-
ning starts the trainer must register the
team and the date of training with the
DGKH. Under the instruction of the trai-
ner the validation team practices the neces-
sary steps using its own, complete validati-
on set within the context of a sample
validation process. The manufacturers of
the equipment should be involved in this
because they can provide valuable informa-
tion on the functions of the equipment
and the processes running. The practical
training also includes using the validation
xxx
aseptica English Edition 2007 9
vered the Mycobacterium
tuberculosis, for which he
received the Nobel Prize
for Medicine in 1905.
This made it possible to
differentiate tuberculosis
on the basis of certain
symptoms and differing
organic effects, to diagno-
se it and to treat it.
The development of
public healthcare systems
along with improved
hygiene and nutritional
conditions made it possi-
ble to drastically reduce
the number of fatalities
resulting from TB in
Europe over the course of the century from
1850 to 1950. Although there was a tem-
porary increase in the number of cases of
the disease after each of the world wars, the
discovery of the antibiotic streptomycin in
1946 and the introduction of the tubercu-
losis drug isoniazid in 1952 led to a conti-
nued reduction in the number of cases.
Epidemiology since 1980
Since the late 1970s and early 1980s there
has been a revival of the infectious disease
TB in Europe and the rest of the world.
The reasons for this are the high mobility
of the population, along with immigration
into all areas of Europe by people from
countries with a high prevalence of TB.
The global increase in the immunodefi-
ciency AIDS and the development of resi-
stance to the established standard treatment
by the tuberculosis bacteria also play an
important role in this epidemiological
development. A large proportion of those
infected with HIV are also carriers of non-
specific tuberculosis, thereby forming a
reservoir for the spread of the pathogens
into the population at large. Both latent
and fresh tuberculosis develop quickly and
in an uncontrolled way into open TB in
persons with an immune deficiency. This
again increases both the risk of spread and
the development of resistant strains of the
bacteria.
Alongside the historical developments
there has also been a change in public per-
ceptions of TB – from a romantic con-
sumption until the 19th century, to the
disease of the proletariat until the early
20th century, through to a marginal disease
nowadays. This has consequences in terms
of the assessment of the risks which are still
associated with tuberculosis today, not only
for doctors in hospitals and general practice
but also for all other nursing staff and for
the patients affected.
Globally 8 to 9 million people become infec-
ted with TB each year. Around 4 million of
these have the highly infectious »open tuber-
culosis« where the bacteria can be detected
microscopically in the sputum. Sub-Saharan
Africa, south and east Asia, some Latin Ame-
Author
Dr Berhard Meyer,
Ecolab GmbH & Co OHG
Ms Marlis Potempa,
FAI Healthcare Germany
Correspondence: Dr Bernhard Meyer
Since the global spread of the immu-
nodeficiency AIDS there has been an
unprecedented spread of tuberculo-
sis on a global scale but in particu-
lar in eastern Europe – the time has
come to address how we can keep
this in check.
Renaissance of an ancient disease
Traces of tuberculosis (TB) have been found
on prehistoric human remains dating from
as early as the year 4000 BC. In around 450
BC Hippocrates described the disease as
Phthysis, which means »wasting« in Greek.
Even at that time it was known as the most
widespread of all diseases, it was almost
always fatal and was for a long time treated
with little success using a »hygienic dietary«
principle with »good food, plenty of rest,
regular changes of temperature«.
Fostered as it was by poverty, poor nutriti-
on and a lack of hygiene, tuberculosis clai-
med over 100,000 lives a year in the Ger-
man empire alone during the industrial
revolution. Despite the fact that the effects
and symptoms of the disease had been
identified and described, for a long time
doctors remained in the dark as to the
aetiology and treatment of the illness –
uneven distribution of body fluids, malign
effluvia from the ground, a general decline
in moral standards and hereditary factors
were all discussed as possible causes.
In Italy it was believed as early as the
beginning of the 18th century that the
disease was communicable. As a result it
was made compulsory to report cases of the
disease in Italy in the mid 18th century and
measures were introduced which served to
reduce the risk of infection. In England as
well the theory of hereditary transmission
held sway for a long time. This first chan-
ged in 1720 with the publication of Benja-
min Marten’s »A new theory of consumpti-
ons«, in which he presented the theory that
the disease was the result of infection by an
infectious agent.«
On 24 March 1882 Robert Koch disco-
Tuberculosis – the current situation
B. Meyer, M. Potempa
In einem medizinisch-diagnostischen Laboratorium werden nach
einer Tuberkulose- Testmethode mittels Venenblut Kontrolltests
durchgeführt.
achtung - BU nochübersetzen
xxx
aseptica English Edition 200710
rican countries and the countries belonging
to the former Soviet Union are worst affec-
ted. And despite the fact that tuberculosis is
treatable, 2 million people die as a result of
the disease every year; more than any other
treatable infectious disease.
The role of tuberculosis in 21st
century Europe
As mentioned above a global reduction in
cases was seen initially. A 10-year trend
from the early 90s showed a continuous
drop or stagnation in the number of cases
of TB in many western European countries.
Subsequently the number of cases of the
disease continued to fall and reached a very
low level in the last few years. The Baltic
states on the other hand saw a steady increa-
se in the number of cases in the late 90s.
This trend only turned around in 2001.
In total 59,497 cases of TB were registered
in the 25 EU states and in Norway and Ice-
land in 2005, with an average of 12.8 cases
per 100,000 inhabitants. It is noticeable
that there was a particularly high proporti-
on of TB cases among immigrants in
western European countries, e.g. Luxem-
burg (68%), the Netherlands (66%), Swe-
den (73%) and Great Britain (64%). In
eastern Europe on the other hand the pro-
portion occurring in immigrants is extre-
mely low – e.g. in Lithuania the rate of the
disease is very high at 75.0 cases per
100,000 inhabitants, but only 3% of cases
in Lithuania occur in immigrants.
In the countries of eastern Europe, the
so-called new independent states (NIS) of
the former Soviet Union, the collapse of
the healthcare systems means that it has not
been and is not possible to provide ongoing
treatment for many TB suffers. This makes
the risk of resistant strains of bacteria deve-
loping particularly high in this patient
group because irregular treatment results in
the pathogen having contact with the the-
rapeutic agent without being completely
eradicated. The geographical proximity of
these areas of eastern Europe and the
migration from them means that the deve-
lopment of TB is significant for Germany
and the other EU countries as well.
Wider involvement of the EU countries
in terms of checking and documenting resi-
stance to medications is urgently needed in
order to enable this health problem to be
more closely monitored.
Tuberculosis treatment today – deve-
lopment of resistance is the greatest
challenge
TB is transmitted by Mycobacterium
tuberculosis which is released when patients
cough or sneeze and which can remain in
room air for a long time. Carriers are
always those who have infectious or »open«
tuberculosis where the focus of the disease
has a connection to the respiratory tract.
In open TB the pathogens can be detected
microscopically in the sputum and bronchi-
al secretion as well as in the gastric juice or
aspiration biopsies. If there is microscopic
evidence of mycobacteria a culture should
always be taken and resistance testing car-
ried out to confirm the findings. X-ray
investigations also play an important role in
the detection and prognosis of pulmonary
tuberculosis.
The incubation period can range from
weeks to many months but the disease
generally develops around six months after
infection. From this point infection can be
detected by means of a tuberculin test even
if there is no actual illness. Only around 5-
10% of people infected with TB actually
become ill; the pathogens often lie dormant
in the body for months or even decades but
can become active and lead to the onset of
the disease if the body’s immune system
become weak – e.g. as a result of old age,
malnutrition or HIV infection.
In line with the course of TB infection we
differentiate between:
■ TB exposure – contact with open TB,
tuberculin test still outstanding
■ TB infection – tuberculin test positive,
no symptoms of the disease
■ TB illness – positive tuberculin test and
symptoms of the disease
■ Primary TB illness – onset of the disea-
se within one month of infection
■ Post-primary TB illness – infection hea-
led, renewed onset after years or decades
In around 80% of people suffering from
tuberculosis the disease manifests as pulmo-
nary tuberculosis but in theory it can affect
any organ.
Standard treatment with antibiotics
Once a diagnosis has been confirmed, or if
TB is strongly suspected, patients are treated
with combination treatment consisting of
several antibiotics which are specifically
effective against Mycobacterium tuberculo-
sis, also called antituberculosis drugs, as
standard. At the beginning of treatment, i.e.
in the initial phase, isoniazid (INH), rifam-
picin (RMP), pyrazinamide (PZA) and
ethambutol (EMB) or streptomycin (SM)
are given for a period of two months. This is
followed by the stabilisation phase, during
which patients have to take a combination
of INH and RMP for at least four months.
Resistance to treatment
Mycobacterium tuberculosis is a bacterium
which grows very slowly and which tends by
its very nature to become resistant because it
is frequently inactive for a long time. For
this reason treatment of open tuberculosis
must last for six months, or considerably
longer in complicated cases where there is
still evidence of bacteria after three months
of treatment.
It is this long duration of treatment
which presents the greatest problem in the
fight against tuberculosis: if treatment is
stopped too soon – either because of poor
compliance or because sufficient, adequate
medicines are not available – it can lead to
the development of dangerous resistance of
strains of the bacteria to the antibiotics used.
Some experts even believe that antibiotic
treatment which is carried out incorrectly
and inadequately is worse than no treatment
at all.
If the bacteria are resistant to more than
two of the antibiotics available it is called
multi-drug-resistant tuberculosis (MDR-TB).
According to the most recent WHO report,
in eastern Europe and central Asia around
15% of new TB infections are now caused by
multi-resistant tuberculosis pathogens and in
Germany the proportion of MDR tuberculo-
sis cases has increased from 2.5% to 2.7%
over the course of just one year.
Another phenomenon which was first obser-
ved in the South African province of Kwazu-
lu Natal in March 2006 is even more worry-
ing. In Kwazulu Natal a strain of TB
bacteria was discovered which is resistant to
almost all second-line medicines. Extensive-
xxx
aseptica English Edition 2007 11
an investigation of the outbreak is neces-sary, coordinated by the health authorityand comprising the following elements:
■ Immediate identification of the pathogen
including culture and resistance testing
■ Establishment and assessment of the
contact history, tuberculin tests, if appro-
priate X-ray examinations and laboratory
testing of the contact persons
■ Physical isolation of the patient if there is
open tuberculosis, even if on a general
hospital ward
■ Good ventilation of the patient’s room
must be ensured
■ The patient should be instructed to cover
his/her mouth with a tissue when coug-
hing, laughing or sneezing.
■ Wearing of protective gowns, masks cover-
ing the nose and mouth (FFP2 masks for
particular exposure, FFP3 masks for
MDR-TB), protective gloves and appro-
priate hand hygiene if there is contact
with material containing the pathogen
■ Complete or partial lifting of isolation is
only recommended after the patient has
been classed as not infectious or, if there is
any doubt, after the patient has been sup-
plied with a mask tightly covering the
nose and mouth.
The implementation of effective disinfection
processes is particularly significant in con-
trolling tuberculosis. Tuberculosis pathogens
have a higher resistance than normal patho-
gens and cannot necessarily be reached by all
disinfectants. In order to ensure that the cor-
rect disinfectant is used to treat surfaces and
instruments and to disinfect the hands, it is
advisable to read the label of the disinfectant
concerned carefully. For everyday use suita-
ble substances are primarily those given in
the list produced by the VAH. Some active
substances are particularly suitable in terms
of how they are handled, their efficacy and
the method of application. This includes the
active substance glucoprotamin.
Although tuberculosis represents a threat
which should be taken extremely seriously,
particularly its highly treatment-resistant
strains, with suitable disinfection measures
and measures to prevent exposure there are
still effective weapons available in the fight
against this disease. ■
Bildtafel aus den 30-er Jahren: Wie schützt
man sich und andere vor Tuberkulose?
ly-drug-resistant strains of TB of this kind
(XDR-TB) have now been diagnosed in 37
countries – with increasing frequency and
alarmingly low chances of recovery.4
Resistance to treatment does not
mean resistance to disinfection
Preventative measures such as actively looking
for cases in persons who have had direct
contact with patients with confirmed open
TB, increased attention to members of special
target groups, for example asylum seekers,
refugees, Ethnic German resettlers [Aussied-
ler], migrants, homeless people, drug users,
and prison inmates, are a requirement if there
are to be high detection rates and a reduction
in the number of cases and the development
of resistance.
Thorough disinfection of surfaces and
medical devices in hospitals, doctors’ practices
and other medical institutes is a particularly
effective and controllable measure to prevent
tuberculosis infections. Special disinfectants are
used for this and these are listed with the
Robert Koch-Institut (RKI) or the Association
for Applied Hygiene (VAH), depending on the
requirements of the situation.
However, the term »development of resi-
stance« is often associated with the idea that
there may also be resistance to disinfectants.
This concern is, however, unfounded because
the effect of biocides on bacteria outside the
human body is different to the effect of syste-
mic antibiotics.
Treatment and disinfection –
different mechanisms
Antibiotics and disinfectants work against
bacteria in different ways. Antibiotics attack
specific cell structures or interact with spe-
cific metabolic/synthesis processes. The
effect of biocides, on the other hand, is
non-specific: they destroy biological mem-
branes and/or react non-specifically with
functional groups of proteins or genetic
material. For example, it has been shown
that at concentrations below the minimal
inhibitory concentration some biocides
initially destroy the functional integrity of
cell membranes and at higher concentrati-
ons then lead to »leakage« of intracellular
material. The possibility of resistance deve-
loping to these non-specific mechanisms is
highly unlikely, in particular because bioci-
dal active agents are used in microbicidal
concentrations far above the minimal inhi-
bitory concentration in disinfectants.
Preventing nosocomial transmission
In view of the fact that only around 10% of
people infected with TB will actually beco-
me ill and that this will normally only hap-
pen in the first two years of having become
infected or even later it is extremely diffi-
cult to identify nosocomial transmission of
TB. Nevertheless cases of nosocomial trans-
mission are described in the literature and
studies reveal that the tuberculin test is
positive more often for those working in
the health service than for the general
population.
In terms of measures to prevent nosoco-
mial TB infections in hospitals and doctors’
practices the public health authorities’ regu-
lations and of course the special guidelines
for the avoidance of hospital infections app-
ly. The guidelines from the German Central
Committee to Combat Tuberculosis (DZK)
in particular should be noted here. If tuber-
culosis is suspected doctors and nursing
staff should complete a risk assessment,
taking into account the epidemiology, the
reservoir and the release of the pathogen,
the infectiousness of the pathogen, the
infection routes and the disposition of the
person exposed.
If there are more than 2 cases of the illnesswith an epidemiologically confirmed link
achtung - BU nochübersetzen
xxx
aseptica English Edition 200712
ebro Electronic, Ingolstadt, has develo-
ped a new software solution
Winlog.med specially for the routine
monitoring/validation of cleaning and
sterilisation processes using datalog-
gers in the CSSD. For CDMs analysis
with the new software is carried out in
accordance with the standards as per
DIN EN 15883-1,2,3 and as per the
draft guideline of the DGKH and DGSV,
for steam sterilisers in accordance
with DIN EN 285, DIN EN 554, DIN
58946-6 and DIN EN13060.
Application in CSSD
Two versions of Winlog.med are available:
■ Standard version Winlog.med: for daily
routine monitoring. It is easy to use,
meaning that even untrained staff can
easily learn how to use it.
■ Winlog.med Validation: this software has
been developed for annual validation.
Winlog.med and Winlog.med Validation
perform fully automated analysis of the
dataloggers used in daily routine monito-
ring and annual validation of cleaning
disinfection machines, bedpan washers and
steam sterilisers. The software independent-
ly identifies and checks the relevant phases
of cleaning/sterilisation, automatically per-
forms all necessary analyses and produces a
quick and accurate assessment of the pro-
cess (pass/fail).
Routine Monitoring
For the daily routine monitoring of CDMs
and bedpan washers the disinfection para-
meters A0-value 60, 600, 3000 and the
temperature-time response are particularly
significant.
For the routine monitoring of steam
sterilisers the pressure-time response and
temperature-time response are documented.
The values are automatically calculated and
represented graphically with the help of the
standard version Winlog.med.
Validation
Winlog.med Validation is suitable for the
validation of CDMs, bedpan washers and
steam sterilisers.
In addition to the features of the stan-
dard version the software also offers »map-
ping«, i.e. the number and position of the
dataloggers is defined in three dimensions
in the software. This means that the exact
position of the loggers inside the equipment
is entered into a three dimensional model of
the CDM or steam steriliser, recording the
serial number, channel and position. The
equipment to be checked is first selected
from a database.
As an automatic result of the CDM
validation using dataloggers Winlog.med
Validation provides a protocol containing
the following information:
■ CDM data: Model, inventory number,
equipment number, program, datalogger
batch, last check
■ Name of the person carrying out the
check (established on the basis of the
electronic signature of the operator,
which must be entered prior to using
the equipment)
■ Positions of sensors, type and serial num-
ber of sensors
■ Program selected
■ calculated and specified A0 value
■ Batch release (yes/no) Automatic reports
are generated for steam sterilisation in
exactly the same way as for CDMs but dif-
ferent information is important for steam
sterilisers:
■ Steam steriliser data: Model,
inventory number, equipment number,
program, datalogger batch,
last check
■ Name of the person carrying out the check
(established on the basis of the electronic
signature of the operator, which must be
entered prior to using the equipment)
■ Positions of sensors, type and serial num-
ber of sensors
■ Program selected
■ Residual air
■ Minimum pressure during vacuum
■ Compensation time, hold time
Author
Susanne Neumann, Marketing
Iven Kruse, Vertriebsleiter
ebro Electronic GmbH & Co. KG,
Peringerstr. 10, D-85055 Ingolstadt
Tel. 08 41/9 54 78-0, Fax 08 41/9 54 78-80
E-Mail info@ebro.de, Web: www.ebro.de
S. Neumann, I. Kruse
New datalogger software for routine
monitoring and validation Winlog.med and Winlog.med Validation
xxx
xxx
aseptica English Edition 2007 13
Interview: on the transmission risk of the
variants of CJD and the decontamination
of surgical instruments(translated from the journal »medical special«
published by the Ith Publishing house)
For patients undergoing operations,
contaminated instruments pose a
certain amount of risk of contracting
the new form of Creutzfeld-Jakob
disease (vCJD). The infectious pro-
teins called prions, which can trans-
mit the disease, adhere well to stain-
less steel surgical instruments and
can only be rendered innocuous with
enormous effort.
British researchers consider it theoretically
possible that in Great Britain iatrogenic
transmission has occurred during operations,
via surgical instruments. Though up to now,
after 160 people have died of vCJD, experts
cannot say exactly how great the risk of con-
traction of infection was and now is. Further
studies will now follow, grounded on the first
data from extrapolations.
In Germany there has not yet been a single
known case of vCJD.We spoke to the post-
graduate Andreas Schmitt at the Centre for
Neuropathology and Prion Research of the
LMU (Ludwig Maximilian University)
Munich, about how medical materials and
diagnostic surgical instrument sets can be
reliably decontaminated, in order to prevent
an iatrogenic transmission of prions.
1. Prion diseases, including amongst
others the different variants of the
Creutzfeld-Jacob disease (CJD), are
really quite rare diseases. Herr
Schmitt- are the risks of iatrogenic
transmission of prions at all relevant
for federal German clinics?
Is iatrogenic transmission possibly relevant
only to certain clinic departments or specia-
list operating sectors?
Although prion diseases may be rare, pre-
vention is of the utmost importance, as the-
re are no available therapies and the disease
is always lethal. The new variant of CJD
(vCJD) caused by BSE is particularly rele-
vant here. Indeed, in Great Britain only
160 people have so far died of vCJD. But
prevalence studies carried out on appendec-
tomy biopsies indicate however a not insi-
gnificant number of infected persons there.
vCJD can be distinguished from the
other human prion diseases by its lym-
photrophism i.e. its potent ability to accu-
mulate infectious prion protein (PrPSc) in
the lymph tissue of infected persons.
Author
Dr Berhard Meyer,
Ecolab GmbH & Co OHG
Ms Marlis Potempa,
FAI Healthcare Germany
Correspondence: Dr Bernhard Meyer
■ Sterilisation temperature reached
■ Temperature range
■ Theoretical temperature
■ F0 value
■ Batch release (yes/no) Each of these values
is assigned an OK/Not OK value by the
software. The relevant value or curve can
be displayed at the click of a mouse but-
ton. The protocol is initially displayed on
screen. However, it can be saved and/or
printed.
Result
The new software Winlog.med and Win-
log.med Validation produced by ebro Elec-
tronic enables the user in the CSSD to
automate routine procedures using a data-
logger and thereby to simplify them. Becau-
se Winlog.med/Winlog.med Validation
have been developed specifically for the
cleaning and sterilisation process in the
CSSD they contain precisely those features
which are needed in this area. ■
achtung - der Autor fehlt noch
xxx
aseptica English Edition 200714
Whereas for the other human prion
diseases PrSc is probably present only in the
CNS and in the eye in quantities relevant
for transmission, vCJD patients also show
large amounts of PrPSc in lymph tissue,
where it is accessible during many surgical
and diagnostic interventions. Because cases
of BSE in cattle in Germany are detected
every now and then, one must presume that
also in this country, the population is expo-
sed alimentarily to the BSE pathogen that
causes vCJD. Even though a case of vCJD
has not yet been detected in Germany,
because of the long incubation time of
vCJD, it is not clear whether any, or how
many people are infected with vCJD, who
could then pose a risk for the transmission
of this disease. In contrast to the other
human prion diseases, where the risk of
iatrogenic transmission is posed first and
foremost by ophthalmic and neurosurgical
operations, vCJD, because of its marked
lymphotrophism, poses a high risk for
transmission of the disease for a large num-
ber of surgical and diagnostic interventions.
Particularly for frequently carried out opera-
tions such as for example, appendectomy or
tonsillectomy, there is direct contact with
the high-risk tissues.
2. Does this have consequences for
the requirements for sterilisation of
materials or for the reprocessing and
disinfection of instruments?
In 2002, because of the background danger
of iatrogenic transmission of vCJD, the
Robert Koch Institute (RKI) extended its
earlier recommendations for instrument
reprocessing. Here they recommend that
instruments that have come into contact
with patients, who are clinically likely to be
suffering from vCJD, should not be repro-
cessed and used again. These instruments
should be disposed of by incineration.
Instruments that cannot be disposed of
because of their high price, should, after
special reprocessing, only be used on pati-
ents with vCJD. If a patient is perhaps suf-
fering from vCJD, then if possible only dis-
posable instruments should be used on him.
These are then disposed of as intended.
Reprocessable medical products should not
be reused until the diagnosis of the patient
is certain. If the diagnosis of vCJD is confir-
med, the instruments can be disposed of; if
vCJD can be ruled out, they can be repro-
cessed.
The RKI also delineates a different pro-
cedure compared to the earlier recommen-
dations for instruments coming into contact
with all other patients who show no sign of
the existence of vCJD. Using a combination
of two at least partially prion-decontamina-
ting procedures, an iatrogenic transmission
of unrecognised vCJD should be prevented.
According to the RKI, the following proce-
dures are at least partially effective against
prions: a thorough alkaline wash; steam ste-
rilisation (preferably at 134°C); or chemical
decontamination with NaOH (1M for at
least an hour), NaOCl (2.5- 5% for at least
an hour, with at least 20,000ppm chlorine
content) or GdnSCN (? 4M for at least 30
minutes).
At any rate, pre-treatment with alcohol
or aldehyde detergents and disinfectants
should be avoided at all costs, as these fix
the infectious prion protein and therefore
can prevent successful decontamination.
3. Are there special diagnostic or sur-
gical instruments or sets of instru-
ments for which the requirements for
cleaning, disinfecting and sterilising
procedures are particularly high?
Instruments that are not readily accessible to
chemical decontamination and cleaning are
especially critical for reprocessing. These
include for example, appliances with narrow
lumina, hollow spaces with only one ope-
ning, or with complex or not readily accessi-
ble surfaces. In addition, for such appliances
the overall optical check of cleaning success
is often not possible.
Because generally physical decontamina-
tion is seen as more reliable than chemical,
this should always be given priority.. Against
this background, the reprocessing of thermo
labile instruments is always critical, because
here the only effective physical procedure
for prion decontamination is steam sterilisa-
tion - which cannot be used.
4. Why are the established cleaning,
disinfecting and sterilising procedu-
res not sufficient for a prion-contami-
nated instrument set?
The inefficacy of many established deconta-
mination procedures lies in the nature of the
prion pathogen. Unlike all the other known
infectious pathogens, prions (PrPSc) consist
only of protein. They do not have other
components such as a lipid envelope or
nucleic acid genome that many of the
decontamination procedures would attack.
In addition, as proteins go, prions have
an unusually high resistance to environ-
mental influences because of their tertiary
structure. So for example, unlike most pro-
teins, prions are partially resistant to enzy-
matic degradation by proteases, and possess
a remarkable resistance to thermal denatura-
tion. Various studies have shown that PrPSc
can partly survive sterilisation in saturated
steam at 134°C and can even maintain its
infectiousness after treatment with dry heat,
possibly even at 600°C.
5. Can one use expensive thermo
labile instrument sets for diagnostic
or therapeutic interventions on CJD
patients?
Certain interventions for CJD patients
require expensive instruments, which due to
their price are not intended to be disposable.
So for example to lay a PEG (percutaneous
endoscopic gastrostomy) for a CJD patient
requires an expensive endoscope. Because
such instruments, even after special repro-
cessing, can only be further used for CJD
patients, some appliance pools for endosco-
pes have been set up, for example at the
University of Göttingen. Here, instruments
especially for the treatment of CJD patients
can be loaned. After use, the loan centre
reprocesses the endoscopes using special
techniques, or disposes of them if necessary.
6. Is there already a standardised,
anti-prion effective approach or
method for cleaning and disinfecting
the various instrument sets?
As mentioned before, the RKI recommends
combining two at least partially effective anti-
prion methods for preventive instrument
reprocessing. On no account may pre-treat-
ments with alcohol or aldehyde detergents or
disinfectants be carried out before the decon-
taminating procedure, because this would
only lead to a stabilisation of the PrPSc.
The simplest attainable approach is the
procedure recommended by the RKI for
xxx
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thermo stable instruments. Here, first alka-
line cleaning in a washer-disinfector appli-
ance is carried out, then steam sterilisation
follows at 134°C for 5-18 Min.
For thermo labile objects one must
resort to other, chemical methods for pri-
on decontamination, rather than using
steam sterilisation. If necessary, after prion
decontamination a low temperature sterili-
sation procedure can be used.
The RKI-recommended procedure is
simply a combination of partially effective
anti-prion methods. These cause a strong
depletion of the adhesive infectivity, but do
not definitely completely eliminate it. In
order to be able to carry out an effective
prevention regarding the iatrogenic trans-
mission of vCJD, new, more effective anti-
prion decontamination procedures for a
wide routine use in instrument reproces-
sing must be developed.
7. Isn’t it true that automatic pro-
cedures are safer than manual pro-
cedures? Is it possible that automa-
tic wash-disinfection procedures are
already being researched?
Of course, normally it is true that automa-
tic procedures produce more steady results
than manual procedures, and therefore
they ensure greater safety in instrument
reprocessing. Also, manual methods can be
problematical regarding the work safety of
the personnel carrying out the procedures.
According to the RKI, from amongst
the at least partially effective automatic
anti-prion procedures- two- alkaline clea-
ning, and sterilisation are established as
automatic procedures. At the moment the-
re is a new, fully automatic procedure,
especially developed for prion decontami-
nation, being tested at our institute. It is a
combined alkaline/oxidative procedure,
which runs in a standard washer-disinfec-
tor appliance. Due to the good material
tolerance and ease of use, it should be
deployable in the general routine reproces-
sing of medical products. During in vitro
experiments we were able to show a reduc-
tion of the infectious prion titre for this
method by as much as 4 log units. At the
moment the method is being tested in ani-
mal experiments. We are expecting the final
results on the anti-prion effectivity of the
new decontamination procedure in August
of this year.
9. With what methods can the
decontamination results be tested?
For the evaluation of new decontamination
procedures, the decontamination result was
checked in quite different ways in separate
studies, which makes a comparison of the
results difficult. So for example, Western
blot-, cell culture-, microscopy- and animal
test-based methods were used to detect pri-
ons. Up to now, from amongst all these
procedures, animal experiments still repre-
sent the gold standard when evaluating new
decontamination procedures.
Herr Schmitt, thank you very much for the
informative discussion!
The interview was conducted by Dr. Win-
fried Michels, Gütersloh. ■
Recent announcement from the Institute ofNeuropathology: in the meantime the in vivoexperiments have been completed, with verypositive results for the Oxivario Plus Process.The results are being prepared for publication.
Recently a manufacturer asked us
what should be included in an
instruction manual for medical devi-
ces. I then realised that the EN ISO
17664 - even three years after com-
pletion- hasn’t found its way into the
instruction manuals proposed by the
legislator, which the user should be
Medical devices require an instruction
manual – is the 17664 helpful?
A manual facilitates handling.
Th. W. Fengler
able to consult (»Manuals«) if he has
a question. Since 2001 in the Euro-
pean Union, the DIN 62079 exists
for authorised devices (EC registrati-
on mark) giving many tips for
assembling appropriate manuals.
The font size must be at least 9, and
a simply formulated description of
Author
Dr. med. Dipl.-Ing. Thomas W. Fengler
CLEANICAL GmbH
Genthiner Str. 11
10785 Berlin
E-Mail: fengler@cleanical.de
xxx
xxx
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man Medical Device Act and its Operator
Ordinance (amongst other things compul-
sory registration) should be followed as
conscientiously as is the case for obligation
to quality management and quality assuran-
ce, according to the Social Security Code
and further compulsory recording, standar-
dising and registration obligations from the
Infection Protection Act.
Guidelines and recommendations have
the character of an anticipated expert’s
report (bear in mind here § 4 of the Medi-
cal Device Operator Ordinance).
Furthermore, necessary care should be
taken during everyday use, to avoid legal
liability and possible fateful and unavoida-
ble complications according to § 276 BGB.
In Germany the KHEntg G (Kranken-
hausentgeltgesetzes- German Hospital
Remuneration Act) (it replaced the Bundes-
pflegesatzverordnung- National Ordinance
on Hospital Rates) is valid and facilitates
across the board retrospective curtailment
of the agreed remuneration (§8 Section 4-
is subject to the WD reimbursement
system according to § 17b KHG) for a pro-
ven deficit in quality management (see
Social Security Code 5th edition).
17664- Part of an extensive body of
rules and regulations
This preview should make it clear that
the handling of medical devices is subject
to an extensive body of rules and regulati-
ons, which the current level of training in
the specialist departments can hardly do
justice to. Manufacturers must also take
this into account when putting medical
devices on the market.
»The Standard applies to medical devi-
ces intended for multiple use and requiring
reprocessing after single use, which returns
them to a sterile state ready for renewed
use.« (Quote : EN ISO 17664).
The Standard does not actually apply
to the clinical use of semi-critical applicati-
ons such as (usually) in the case of (flexible)
endoscopes, but »the principles of this
Standard can be followed for medical devi-
ces only requiring final disinfection before
reuse, if the information made available for
these medical devices is taken into account.«
If the responsible parties require sterili-
sation of devices because of the scope of the
therapeutic intervention, then sterilisation
becomes mandatory, for example the use of
a flexible bronchoscope for active tubercu-
losis. This is why we recommend a suitable
formulation in the manual or instructions
for use.
Furthermore: »This Standard specifies
information that must be provided by the
manufacturer about the reprocessing of
medical devices if these are claimed to be
resterilisable, or if they should be sterilised
by the reprocessor.«
»This Standard specifies requirements
for the information provided by the manu-
facturer of the medical devices, that serve
safe reprocessing and maintenance of the
required performance capability of the
medical devices.«
This includes prearrangement at the
place of use, the preparation, washing and
disinfection in the reprocessing depart-
ment, drying, monitoring, servicing and
checking, packing and sterilisation also in
the reprocessing department, as well as sui-
table storage.
Particularly interesting is the relativising
remark about concrete reprocessing conditi-
ons! »For preparing instructions/direc-
tions… the manufacturer…is urged to take
into account training, process knowledge
and the provisions for reprocessing that
persons likely to carry out reprocessing
have available to them. Some of the repro-
cessing methods are probably of a general
nature...in this case the instructions need
only give a suitable reference.«
As well as the field of application (sec-
tion 1), it makes sense to put in the terms
(section 2) used in the Standard so as not
to bewilder the user. Here, in our opinion a
corresponding discussion of technical terms
should be added for each block of text in
the manual. Using a washer-disinfector
appliance is obviously rather different to
using a laundry washing machine or dish-
washer, which by definition are not medical
devices, but nevertheless are used variously
in reprocessing.
Section 3 stipulates as mandatory a
validated reprocessing method, which
should be cited, giving a specification for
this statement in the informative annex A.
Here manual cleaning- by the way quite
the intended use of the device must
be given, with relevant warnings
where necessary.
For medical devices, as well as a description
of function, how to reprocess them is
described as a sort of »maintenance measu-
re«. The instruction manual is therefore an
indispensable part of quality-ensuring
management and describes intelligibly the
function and care of a medical device. In
the case of a reprocessable medical device it
also includes information on manual and
automatic reprocessing.
By mentioning the RKI guideline on
hygiene (2001), the Medical Device Act
and its Operator Ordinance strongly
recommend risk group categorisation accor-
ding to design (C, B, A) and field of appli-
cation (critical, semi-critical, non-critical).
Each and every correspondingly autho-
rised medical device is intended for use
on/in patients and must correspond to spe-
cial European (EC registration mark, Gui-
deline 93/42/ EWG) and national legislati-
on (the Medical Device Act, its Operator
Ordinance, as well as directives about elec-
trical safety, the Regulation of Biological
Substances Act and general liability).
Thus for resterilisable medical devices,
there is the EN ISO 17664, containing a
framework for reprocessing. A correspon-
ding (descriptive) standard for disinfectable
medical devices does not exist; the one
mentioned here can however definitely be
applied appropriately. For the process stages
of automatic cleaning and disinfection of
medical devices, the CEN ISO 15883 is
now valid. For the process stage of sterilisa-
tion, the DIN EN 285 is valid among
others.
The EN ISO 15883 1-5 contains infor-
mation on the processing step cleaning and
disinfection. One manual should take into
account the total cycle of use of a medical
device, from preparation for use to disposal
and reprocessing for reuse on the next (or
the same) patient.
Disposable instruments are by definiti-
on manufactured only for single use (only)
on one patient.
Acts and statutes are granted absolute
binding character in German law. The pro-
visions of the European directives, the Ger-
xxx
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realistically- is explicitly not excluded.
What such a »validated« method should be
like is however not explained. The possibili-
ty of limiting the number of cycles is also
mentioned- without description of a tech-
nique- if the life expectancy of the medical
device is limited by wear and tear. Finally
the process stages are described one by one.
A suitable comparison with already existing
text blocks from existing manuals is recom-
mended and should be applied gradually to
new manuals.
Section 4 describes the presentation of
information (see also appendix B).
A cross reference of contents for the
body of rules and regulations should be
provided in the relevant text blocks. » The
information specified in section 3 (»Infor-
mation to be provided by the manufactu-
rer«) should take into account the pro-
perties and condition of the medical
devices, the intended use, as well as the
training and level of knowledge of the per-
sons responsible for the reprocessing«. In
particular it is pointed out that cross refe-
rences to standards and manufacturers’
information is also permitted in the form
of symbols (such as »EN ISO 15883«).
Section 5 requires the validation of
each and every method used in a process;
this can also be carried out as group valida-
tion.
Thus it can be differentiated between
dismantleable and rinseable instruments.
Regarding the risk analysis in Section 6
based on the nature of and intended appli-
cation of the medical device in question,
one is referred to the training level and
technical provisions of the reprocessor (per-
son). The EN ISO 14937 is named as a
guideline.
In Appendix A process classification of
methods A-J can be undertaken. In Appen-
dix B there is a form for reprocessing
instructions. Both are informative, rather
than normative appendices. Here the Stan-
dard supports in parts the Guideline
93/42/EWG and has a literature appendix
containing those standards thought to be
relevant- (general and specific information
about sterilisation, validation, packing and
symbols for registration marks).
In our opinion this Standard EN ISO
17664 should be made available to the
customer in its entirety. This does not
mean that the manufacturer has to have his
own reprocessing manual available on
request- on the contrary: the 17664 was
written precisely so that it could be referred
to in the stipulated instruction manual.
Thus it is not necessary to describe in detail
for every new manual what is actually pre-
sented in the Standard. A reference to the
relevant group suffices. It should be possi-
ble for this Standard to gain international
acceptance, because manual cleaning is
deliberately not excluded.
Chapter 3 explicitly requires »a valida-
ted (!) non-automatic disinfection method«.
However it can be presumed that the Stan-
dard is not (yet) very well known and the-
refore national regulations play a more
important role, as far as they exist in each
exporting country.
In particular the criteria for classificati-
on of what should be sterilised are not con-
gruent between America, Asia and Europe.
The user, called the »reprocessor« in the
Standard, usually follows local norms/stan-
dards, which are now being amended and
being rendered more precise through this
global standard.
In the past much of the information
mentioned and required in the Standard
has not been gathered and documented, so
that a substantial adaptation phase is requi-
red. Precisely because of this, it is vital that
the phrasing of the manual should be clear
and conform to the body of rules and regu-
lations. In particular the terms for (process-
) validation (Installation validation, Opera-
tional validation, Performance validation)
are shown over and over again to be
unwieldy.
The scope of the process parameters to
be specified will continue to grow because
of continuing improvements in the specifi-
cation of reprocessing steps. This is accom-
modated better during customer service
than in the manual itself.
Nevertheless the contents of CEN ISO
17664 can be designated as generally spea-
king practicable. Here some phrases signal
a certain leeway - such as »The following
information should be cited if it is critical
to maintain the intended function of the
medical device and to ensure the safety of
the user and patient« or »if necessary« or »if
applicable« (Section 3).
»Thresholds...of chemical residues
remaining on the device« need only be
cited by the manufacturer »if and when it is
necessary«.
The manufacturer can provide infor-
mation here, nevertheless the reprocessor
decides whether his specifically chosen (or
simply long-established) methods could
cause damage to instruments.
The patient is expected to have few
problems with »maximally residue-free«
instrument surfaces, and only in exceptio-
nal cases could proof of damage be used as
a reason for a liability case. This is why the
legislator emphasises the utter necessity of
validated reprocessing processes - that must
also be attestable (compulsory documenta-
tion – for one’s own benefit). Process safety
leads to more legal safety!
A different situation applies to disinfec-
tant concentration and contact time, which
must be specified for the process - first as
evidence of proper functioning and second-
ly with regard to patients. The disinfectant
must then be removed from the medical
device –another requirement that is also
not described in detail or verifiable. Here
too one must be able to substantiate the
customary methods, such as rinsing with
fully demineralised water (documentation).
To summarise, the realisation lingers
that the contents of this Standard are not
nearly sufficiently familiar, nationally or
internationally. It offers the user something
useful, because categories and their criteria
are named, which can facilitate validated
reprocessing.
Only measurable processes can be suffi-
ciently documented and offer, in the event
of a liability claim, the necessary proof that
work was done according to the latest
scientific and technical knowledge. ■
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Experience gathered from automatic
instrument reprocessing in an ophthalmic
clinic
U. Roider
Ophthalmic surgical operations in an
ophthalmic clinic take place primari-
ly as outpatient procedures and con-
cern the anterior and posterior
chambers of the eye. Interventions
include cataract and glaucoma sur-
gery, corneal transplantation (kera-
toplasty), vitrectomy, as well as
every type of refractive surgery.
Until 2003, instruments were exclusively
reprocessed manually, using ultrasound tre-
atment. After successfully completing the
training course Technical Qualification 1, I
started to plan the adaptation of reproces-
sing to fit the requirements of the relevant
specialist guidelines and recommendations.
The processes should be validated through-
out and the reprocessing must be recon-
structable from the documentation to aim
at the best possible legal certainty. We have
always endeavoured to offer our patients
the best possible quality and the results of
innovation, which is expressed by our
achievement of the ISO certificate. The
changeover from manual to automatic
reprocessing involved quite a few challen-
ges. First the small reprocessing area had to
be adapted structurally to accommodate the
necessary appliances, while taking into
account the hygienic aspects of the organi-
sational and spatial layout. Within this fra-
mework, the entire reprocessing equip-
ment- the washer-disinfector appliance (WD), the steam steriliser, right through to
the (Durchlaufsiegelgerät) sealing machine-
was brought up to date technically. The
choice of WD was restricted to a one door
appliance i.e. front-loading, because of spa-
tial considerations. The instruments and
the six already available sieve baskets were
tested for their automatic reprocessability,
according to the information provided by
the manufacturers. They were augmented
with 24 sieve baskets. We were unsure in
particular about whether diamond blades
could be reprocessed automatically in a
WD. Before buying new blades we made
sure that automatic reprocessing is suitable
here.
For cleaning in the WD we chose to
use an alkaline process chemical recom-
mended by the RKI Task Force vCJK,
which according to manufacturer’s informa-
Author
Ulrike Roider
Augenklinik am Marienplatz
Marienplatz 18
80331 München
Tel.: 089/23 24 10-0
Figure 1: WD with loading trolley for ophthalmic operation instruments
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tion realises a pH of almost 12. This is
added after an intensive pre-rinse, in the
cleaning phase at 55°C, with a holding
time of 10 minutes. Neutralisation then
followed, an intensive mid-wash rinse, ther-
mal disinfection with an Ao value of more
than 3000 and finally drying. The WD is
equipped with the corresponding loading
trolley for ophthalmic surgical instruments,
which can be loaded with up to 8 sieve bas-
kets. Thus we have the capacity for dealing
with days where as many as 40 operations
take place. We have found our own soluti-
on with regard to instrument sieve baskets,
customising them for use with ophthalmic
instruments. We obtained sieve baskets
designed for instrument reprocessing in the
dental area, and had them fitted with stora-
ge racks made of knobbed mats. These
were also punched with holes so that the
instruments could be wetted more effec-
tively and so that water could run off easily.
We have come to regard suction- rinse
handles as disposable, as they are quite
cheap and we don’t think the constructio-
nal »cul-de-sac« at the tip can be properly
cleaned automatically. In the same way, the
narrow internal diameters of Sautter cannu-
lae have been replaced with disposable pro-
ducts, after initial reprocessing of the can-
nulae without water filtration often led to
blockages. Other hollow instruments such
as ultrasound handles and Klöti strippers
with magnetic drives are always carefully
Figure 2: Instrument sieve baskets with integrated storage racks
connected to the wash adaptor and there
have never been any problems here. Hollow
instruments are checked for tubal patency
before being washed. After the wash process
the connections are checked to make sure
they are still correctly attached. In the very
rare case of a wash connector becoming dis-
connected, the relevant instrument is put
back to undergo another reprocessing cycle.
Every day as a spot check, a Phako handle
is tested for residual alkalinity. Here some
residual water from the instrument is drop-
ped onto pH paper and the colouration is
compared to the table? Over the last 4 years
we have never had a result that gave cause
for concern.
In the last few years no instrument
damage has been caused by automatic
reprocessing. Wear and tear has been great-
ly reduced due to the greater number of
instrument sieve baskets. The two or three
instruments per month that are sent to be
repaired are primarily damaged through
inappropriate use or an accident. Because
the fully demineralised water for the final
rinse is prepared using an ion-exchange car-
tridge, there was initially a discolouration
problem due to silicate accumulation and
escape, which was solved by putting two
cartridges in series.
The wash-disinfection process was
meanwhile re-validated for the fourth time.
This took place according to the DGKH,
DGSV and AKI guidelines. The WD is run
through a series of checks during the mor-
ning of each working day. Here checks are
made to ensure the patency of the nozzles,
that the spray-arms are free to move, that
the connection of the loading trolley to the
wash/rinse water is correct, that sufficient
process chemicals are available etc. After
each load has been reprocessed, the clea-
ning result is optically checked. The quality
of hollow cavity washing is checked weekly
using a test object and once a month the
WD is put through thermal checks using a
temperature logger. For some time now we
have had the WD connected to a personal
computer for process documentation so
that we can monitor the process during the
cycle. At the end of the cycle the protocol
is checked and the load is then released by
the data processing programme if all para-
meters have been attained. ■
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Maintaining the function of surgical
instruments using sterilisable oil
Some basic considerations should
be taken into account in regards to
wear and corrosion protection when
using sterilisable oil for instrument
maintenance. This report shall iden-
tify the need to use sterilisable oils
to ensure the functional, long-term
use of surgical instruments.
Surgical instruments generally consist of
various components, whose surfaces are
exposed to a relative motion when using
the instrument.
Poor conditions can then lead to instru-
ment damage. The science of tribology
describes the interactions of solid bodies in
relative motion.
2 Tribology
The term »tribology« originates from Gre-
ek and is made up of the words »tribein« =
to rub and »logia« = sayings, words or dis-
W. Fuchs and M.Gaißer
courses (translated literally »friction tea-
chings«).
The elementary keywords of tribology
are friction, wear and lubrication. To deve-
lop an understanding of the processes of
friction, wear and lubrication, some basic
knowledge and definitions are required,
which are presented in the following.
2.1. The tribological system
A tribological system (see Figure 1) consists
of a basic part and an opposing contacting
part, e.g. the case part and insertion part of
a clamp, the upper and lower part of scis-
sors or the rigid or movable part of a
punch. The basic part and opposing
contacting part are in relative motion to
each other (see Figure 2). An interfacial
medium (e.g. lubricants, wear debris, oxide
layers) can in turn be introduced between
the surfaces of the basic part and opposing
contacting part. All three components find
themselves in a surrounding medium such
as air, water, etc.
As already mentioned, friction and
wear processes take place on the surfaces of
the affected system components. Therefore,
more specific attention is paid to the surfa-
ce structure and surface topography.
2.1.2 Structure and topography
of a technical surface
Technical surfaces can be afflicted with
impurities in areas near the surface. These
can involve, for example, surgical residues
in the case of used surgical instruments.
Metallic materials usually have a ultra-thin
oxide layer, which in the case of stainless
steel works to protect against corrosion. In
front of the base material, technical surfaces
have an area of malleable deformations cau-
sed by e.g. grinding, pressing or rolling
processes. (see Figure 3)
A technical surface appears level and
smooth when viewed macroscopically.
However, this perception is incorrect. Vie-
wed microscopically, the surface appears as
a highly fissured »andscape« with rough
peaks and valleys (see Figure 4).
2.1.3 Friction
If two technical surfaces find themselves in
relative motion to each other, the respective
peaks catch (see Figure 5), which in turn
causes resistance to the relative motion.
This resistance is described as friction.
The friction causes the rough peaks to she-
ar off, which over the course of time leads
to surface wear. Depending on the type of
tribological system, i.e. the material combi-
Author
Wolfgang Fuchs
Marco Gaißer
Aesculap AG & Co. KG
Am Aesculap Platz
78532 Tuttlingen
E-Mail : Wolfgang.Fuchs@aesculap.de
Figure 2: Model of relative motion transferred to punches, scissors and clamps
Figure 1: Tribological system
Figure 3: Structure of a technical surface
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nation of the basic part and opposing
contacting part and the type of interfacial
and surrounding medium (see Figure 1),
various wear patterns are observed. The
types of wear and their mechanisms which
affect surgical instruments, e.g. sponge for-
ceps according to Förster, shall be introdu-
ced in the following. The mechanisms and
manifestations can be applied to all other
multi-component instruments, whose indi-
vidual components are in relative motion to
each other.
2.2 Wear
2.2.1 Sponge forceps according to
Förster
Figure 6 shows the sponge forceps accor-
ding to Förster BF122R, which are used to
explain the types of wear and their mecha-
nisms.
The sponge forceps according to För-
ster were prepared once, where a special
cleaning method was used. For this
method, a substance with an oxidising
effect (H2O2) is added to the cleaning
agent. This supports the cleaning/degrea-
sing of heavily contaminated instruments
or burned-in surgical residues in HF sur-
gery, which is the primary goal of cleaning.
A widely-used preparation process of this
type is the Oxivario process from Miele (see
Figure 7). Our research showed a residue-
and oil-free surface.
Even after a single use and preparation,
a functional check shows that the instru-
ment becomes difficult to to open and clo-
se. The contact surfaces exhibit mechanical
damage (see Figure 8). This damage can be
attributed to 2 wear mechanisms:
2.2.2 Abrasive wear
Abrasive wear leads to micro chipping on
the basic part and opposing contacting part
due to friction. Abrasive wear is revealed on
the surfaces of the contacting parts and is
usually clearly identifiable wear debris (see
Figures 9, 10, 11).
Abrassive wear is promoted when the
basic part and opposing contacting part
have differing hardnesses or there is an
additional hard phase between the basic
part and opposing contacting part. This is
particularly evident with orthopaedic or
bone surgical instruments, whereby bone
residue not removed can lead to a so-called
»three-body wear« (see Figure 12).
Contamination (see Figure 3) such as
encrusted blood
can also induce
increased abrasive
wear within the
contact surfaces.
Three-body wear
Remedial action
■ Lubrication to separate basic part and
opposing contacting part
2.2.3 Adhesive wear
With adhesive wear, the rough peaks are
first malleably deformed. In the case of
stainless steels, which are used for surgical
instruments, the corrosion-resistant oxide
layer is destroyed. It then leads to an inter-
facial connection of the basic part and
opposing contacting part (see Figure 1).
This connection leads to a stop of the
relative motion colloquially described as
»seizing«. If the force of the relative motion
is large enough, it can lead to the breakout
of the connected contact areas. Material is
transferred from one contacting part to the
other. Adhesive wear is revealed by material
transfer or breakout (see Figures 13, 14, 15).
Remedial action:
■ Lubrication to separate basic part and
opposing contacting part
Figure 4: Macroscopic and microscopic representation of a technical surface
Figure 5: Development of friction
Figure 8: Mechanical damage
Figure 6: Sponge forceps according to Förster Figure 7: Oxivario process [source: Miele]
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xxx
3 Cause of signs of wear
The cause of signs of wear and the associated failu-
re of the instrument can be attributed to the non-
lubrication or insufficient lubrication of the instru-
ment after the preparation process.
Precision-fitting, high-quality instruments are
particularly susceptible to an increased risk of wear.
Therefore, the long-term use of an instrument can
only ben ensured by the regular and purposeful
lubrication of the contact surfaces (see Figure 16).
The lubricant minimises the contact of the rough
peaks and thus reduces the effect of friction. The
lower the effect of friction, the lower the risk of wear.
Conclusion:
When using special cleaning methods in particular,
instruments that are not maintained can wear very
quickly. Only regular, purposeful lubrication ensu-
res the conservation of value and the long-term use
of high-quality and expensive instruments. ■Figure 9: Traces of abrasive wear
Figure 10: Light microscopic representation of wear debris
Figure 11: Electron microscopic representation of wear debris
Figure 12: Bone residue in a punch and thus
induced three-body wear
Figure 13: Light microscopic representation
of a material transfer
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achtung - bezeichnungennoch deutsch
aseptica English Edition 2007 23
xxx
Scientific Advisors:D. Bremer, Harderberg; U. Junghannß, Köthen;Th. W. Fengler, Berlin; T. Miorini, Graz; M. Pietsch, Mainz; B. Schmidt-Rades, Gütersloh;E. Schott, Essen; B. Wilbrandt, Berlin
Published by:medienfabrik Gütersloh GmbHCarl-Bertelsmann-Str. 3333311 GüterslohTelefon: 0 52 41/2 34 80-50Fax: 0 52 41/2 34 80-61ISDN: 0 52 41/2 34 80-64E-Mail: info@aseptica.comInternet: www.aseptica.com
In cooperation with:Ecolab GmbH & Co OHGEuropean Headquarters, P.O. Box 13 04 0640554 Düsseldorf;Miele & Cie. KG, 33325 Gütersloh;OLYMPUS Medical Systems Europa GmbHP.O. Box 10 49 08, 20034 Hamburg;ebro Electronic GmbH & Co. KGPeringerstraße 10, 85055 IngolstadtCLEANICAL®, Kranoldstraße 24, 12051 Berlin
Responsible for contents:Reinhild PortmannPublic Relations OfficeMiele & Cie. KGCarl-Miele-Straße 2933332 GüterslohTelefon: 0 52 41/89 19 52Fax: 0 52 41/89 19 50
Editors:Klaus-Peter Becker, Ecolab, Dr. Klaus-PeterBansemir, Ecolab, Dr. Winfried Michels, Miele,Thomas Brümmer, Olympus, Iven Kruse, ebro,Helmut Pahlke, Cleanical
Implementing, layout and printing:medienfabrik Gütersloh GmbHGuido Klinker, Sebastian Borgmeier
Edition: 4.000
Title topic:mauritiusimages
Frequency:Printed quarterlyPrinted on paper processed chlorinefree
Reproduction only with editor’s permission. Indi-vidual contributions may deviate from the opinionsof the publishers. No liability is taken for unsolicit-ed manuscripts and photos. The editors reserve theright to shorten readers’ letters.
ISSN 1439-9016
Imprint
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Werkstoffprüfung, 14. Auflage, Vieweg &
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[2] Heine B., Werkstoffprüfung Ermittlung
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Werkstoffen, IT’S T.I.M.E. / 02/02
[5] Czichos H., Habig K.H., Tribologie,
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[6] Fleischer G., Gröger H., Thum H., V
erschleiß und Zuverlässigkeit, Berlin: Verlag
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[7] Zum Gahr, K.H., Microstructure and
wear of materials, Niederlande Elsevier 1987
[8] Arbeitskreis Instrumentenaufbereitung,
Instrumentenaufbereitung richtig gemacht,
8. Ausgabe 2004
[9] Wissenschaftliche Information, Sterilität
unter Ölfilmen bei Instrumenten und
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on im Selbstverlag der Aesculap AG & Co.
KG, Aesculap C- 511-01 798/2, 3. Aufla-
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[10] Michels W., Pieper M., Optimierte
Figure 14: Electron microscopic representa-
tion of a material transfer
Figure 15: Side view of material breakout on
the insertion part
INCORRECT CORRECT
large-area coating of targeted oils of the contact areas
insufficient lubricating effect
Obstruction of the recleaning and sterilisation
unnecessary high consumptionof oil (avoidable costs)
unnecessary burden on space/air
Abbildung 16: Schmierung richtig gemacht
maschinelle Reinigung mit oxidativer Ver-
fahrensstufe, Aseptica 9. Jahrgang 2003,
Heft 4 S. 6,7
[11] Geibel U., Sommer N., Erste Anwen-
dungserfahrungen mit dem Reinigungs- /
Desinfektionsverfahren OxiVario Plus,
Aseptica 9. Jahrgang 2003 Heft 4 S.8,9
Literature
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