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Cost analysis of machine and manual reprocessing of
transvaginal ultrasound probes
Kostenanalyse maschineller und manueller Aufbereitung transvaginaler
Ultraschallsonden
Abstract
Objective: This study aims to provide additional support for the equip-
ment needed in hospitals and medical practices for reprocessing Denise Kiefner1
Hicham Benkhai1
transvaginal ultrasound probes (TVUS) through an economic analysis Sandra Lemanski2
comparing manual and automated reprocessing methods. A question-
Marc Thanheiser3
naire survey was also conducted in hospitals and medical practices to
analyze the current practice of TVUS reprocessing. Axel Kramer1
Methods: The economic analysis compared four manual reprocessing
methods using disinfection wipes and one automated device-based
disinfection method using hydrogen peroxide vapor. The working times 1 Institute of Hygiene and
Environmental Medicine,
were measured with a stopwatch and complemented by passive working University Medicine
time (disinfection exposure time or machine cycle duration). The person- Greifswald, Greifswald,
Germany
nel costs for the working time were calculated and combined with the
calculated acquisition and material costs to determine the total process
costs. 2 Department of Psychology,
Chair of Health and
Results: The economic analysis revealed that machine disinfection is
not only time-saving but also more cost-effective per reprocessing cycle Prevention, University of
Greifswald, Greifswald
Germany
compared to two manual methods using wipes for cleaning and disin-
fection, where the disinfectant is applied to the wipe before use. How-
3 Division Hospital Hygiene,
Infection Prevention and
ever, two methods using ready-to-use (rtu) disinfection wipes from a
container were more cost-effective. It is important to note that all wipe Control, Department of
disinfection methods would incur additional costs due to the lack of Infectious Diseases, Robert
validation. The additional costs for validation could not be calculated Koch Institute, Berlin,
Germany
due to a lack of experience, making a final cost assessment for wipe
disinfection methods currently impossible.
Despite extensive efforts to send the survey to hospitals and medical
practices through three professional societies and attempts to acquire
participants via a publication, only 35 institutions participated. Except
for one case, all reprocessed manually. The survey revealed a deficit in
knowledge regarding TVUS reprocessing. Manual reprocessing had not
been validated despite national legal requirements existing since 2002.
Conclusion: As long as manual reprocessing is not validated in all steps,
only machine reprocessing is ethically acceptable for patient safety.
Even if manual wipe disinfection is validated, machine reprocessing
offers higher patient safety, since deviations from the validated SOP
cannot be excluded during manual execution. Machine reprocessing
should always be preferred for occupational safety reasons.
Since the process costs for methods involving the application of the
disinfectant to the wipe before disinfection were higher than for the
machine method, the latter is preferred in this comparison. It is not
possible to determine whether the overall process is economically su-
perior to machine reprocessing because the cost calculation for rtu
disinfection wipes does not include the entire process of reprocessing,
including the legally required validation. Due to the better standardiza-
tion of the machine reprocessing process, along with increased proce-
dural, worker, and patient safety, machine reprocessing should be
preferred regardless of process costs, especially if the economic differ-
1/11GMS Hygiene and Infection Control 2024, Vol. 19, ISSN 2196-5226
Research Article
OPEN ACCESS
ence is not significant. Additionally, avoiding disposable wipes is bene-
ficial in terms of sustainability.
The lack of knowledge regarding national legal requirements and recom-
mendations for TVUS reprocessing is a reason why the principles of re-
processing were not adhered to in several practices. Therefore, it is
necessary to convey the basic knowledge of reprocessing during med-
ical studies, followed by further training during specialization. Persons
tasked with reprocessing must have the required education or partici-
pate in specialized training to demonstrate current knowledge (§ 8 Sect.
7 Medical Device Regulation).
Keywords: TVUS reprocessing, manual reprocessing, machine
reprocessing, economic analysis, process time, personnel costs, material
costs, survey results on reprocessing practices
Zusammenfassung
Zielsetzung: Mit Hilfe einer Wirtschaftlichkeitsanalyse von manueller
und apparativer Aufbereitung transvaginaler Ultraschallsonden (TVUS)
sollte eine zusätzliche Hilfestellung für die zur Aufbereitung von TVUS
erforderliche Ausrüstung von Krankenhäusern und Arztpraxen gegeben
werden. Begleitend sollte eine Fragebogenerhebung in Krankenhäusern
und Arztpraxen durchgeführt werden, um die derzeitige Praxis der Auf-
bereitung von TVUS zu analysieren.
Methode: Die Wirtschaftlichkeitsanalyse wurde für vier Verfahren der
manuellen Aufbereitung mit Desinfektionstüchern (Wipes) und ein au-
tomatisiertes apparatives Desinfektionsverfahren auf Basis von Was-
serstoffperoxidverneblung durchgeführt. Die Arbeitszeit wurden mittels
Stoppuhr bestimmt und durch die passive Arbeitszeit (Einwirkungszeit
der Desinfektion bzw. Zeitdauer des Programmdurchlaufs der Maschine)
komplettiert. Für die aufgewendete Arbeitszeit wurden die Personalkos-
ten kalkuliert und durch Addition der kalkulierten Anschaffungs- und
Materialkosten der Gesamtprozess berechnet.
Ergebnisse: Die Wirtschaftlichkeitsanalyse ergab, dass die maschinelle
Desinfektion nicht nur zeitsparender als die manuelle Wischdesinfektion
ist, sondern pro Aufbereitung im Vergleich zu zwei manuellen Verfahren
mit Einsatz von Tüchern zur Reinigung und zur Desinfektion, bei denen
das Desinfektionsmittel vor der Anwendung auf das Tuch gegeben wird,
auch kostengünstiger ist. Dagegen erwiesen sich zwei Verfahren mit
zur fortlaufenden Entnahme aus einem Behältnis befindliche ready-to-
use (rtu)-Desinfektionswipes als kostengünstiger. Hierbei ist zu beach-
ten, dass für alle Desinfektionsverfahren mittels Wipes aufgrund der
jeweils noch ausstehenden Validierung zusätzliche Kosten berücksichtigt
werden müssten. Die hierfür entstehenden zusätzlichen Kosten konnten
mangels Erfahrungswerten nicht einberechnet werden; somit ist derzeit
für Desinfektionsverfahren mittels Wipes keine abschließende Kosten-
abschätzung möglich.
Trotz umfangreicher Bemühungen durch Versendung der Umfrage an
Kliniken und Arztpraxen, an drei Fachgesellschaften und den Versuch,
durch eine Veröffentlichung Teilnehmer zu akquirieren, nahmen nur
35 Einrichtungen an der Umfrage teil. Mit einer Ausnahme wurde nur
manuell aufbereitet. Die Befragung ergab ein Defizit im Kenntnisstand
zur Aufbereitung von TVUS. In keinem Fall war die manuelle Aufberei-
tung, trotz der seit 2002 existierenden nationalen rechtlichen Vorgaben
in der MPBetreibV, bisher validiert worden.
Schlussfolgerung: Solange die manuelle Aufbereitung nicht in allen
Teilschritten validiert ist, ist im Interesse der Patientensicherheit nur
die maschinelle Aufbereitung ethisch vertretbar. Selbst wenn die manu-
elle Wischdesinfektion validiert worden ist, bietet die apparative Aufbe-
reitung die höhere Patientensicherheit, weil bei manueller Durchführung
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Kiefner et al.: Cost analysis of machine and manual reprocessing of ...
Abweichungen von der auf der Grundlage der Validierung definierten
SOP nicht auszuschließen sind. Auch aus Arbeitsschutzgründen ist der
apparativen Aufbereitung immer der Vorzug zu geben.
Da die Prozesskosten bei beiden Verfahren mit Auftragung der Desin-
fektionslösung auf das Wipe vor der Desinfektion höher waren als bei
dem apparativen Verfahren, ist letzteres in diesem Vergleich zu bevor-
zugen. Da bei den rtu- Desinfektionswipes die Kostenkalkulation nicht
den Gesamtprozess der Aufbereitung einschließlich der gesetzlich ge-
forderten Validierung abbildet, lässtsich nicht ableiten, ob der Gesamt-
prozess ökonomisch der apparativen Aufbereitung überlegen ist. Da
die Durchführung der apparativen Aufbereitung besser standardisierbar
ist, verbunden mit erhöhter Verfahrens-, Arbeitnehmer- und Patienten-
sicherheit, ist unabhängig von den Prozesskosten der apparativen
Aufbereitung der Vorzug zu geben, zumal wenn sich die Wirtschaftlichkeit
nicht erheblich unterscheidet. Auch im Hinblick auf Nachhaltigkeits-
aspekten ist eine Vermeidung von zu entsorgenden Wipes zu begrüßen.
Die z.T. fehlende Kenntnis der nationalen gesetzlichen Vorgaben und
Empfehlungen zur Aufbereitung von TVUS ist als ein Grund dafür anzu-
sehen, dass die Grundsätze der Aufbereitung in mehreren Praxen nicht
eingehalten wurden. Daraus ergibt sich die Notwendigkeit der Vermitt-
lung des Basiswissens zur Aufbereitung bereits im Medizinstudium mit
nachfolgender Vertiefung in der Weiterbildung. Auch die mit der Aufbe-
reitung beauftragten Personen müssen über eine erforderliche Ausbil-
dung verfügen bzw. es kann für den Nachweis der aktuellen Kenntnis
die Teilnahme an fachspezifischen Fortbildungsmaßnahmen berück-
sichtigt werden (s. § 8 Abs.7 MPBetreibV).
Schlüsselwörter: Aufbereitung von TVUS, manuelle Aufbereitung,
apparative Aufbereitung, Wirtschaftlichkeitsanalyse, Prozesszeit,
Personalkosten, Materialkosten, Umfrageergebnis zur
Aufbereitungspraxis
Introduction
The reprocessing of medical devices (MDs) intended for
almost sterile or sterile use must be performed with val-
idated procedures to ensure patient safety [1], [2]. This
includes all steps of reprocessing, such as pre-cleaning,
cleaning, disinfection, removal of cleaning and disinfec-
tant residues, and final sterilization for sterile MDs. The
type testing for machine cleaning-disinfection procedures
is regulated by standards. Automated reprocessing
methods are validated according to similar principles.
Manual reprocessing with a wipe procedure must also
validate all steps such as precleaning, cleaning, interme-
diate rinsing, disinfection, and final rinsing [3], [4]. The
procedures must be documented in a standard operating
procedure (SOP), and the personnel must be trained ac-
cordingly. Although there is a guideline for manual repro-
cessing [5], MDs requiring wipe disinfection are excluded
from its scope. However, manual immersion disinfection
is included and considered validatable, because the ex-
perimental process of immersion is covered by the test
methods of the Association for Applied Hygiene (VAH),
ensuring reproducible application by the operator on-site
[1], [6], [7]. It is crucial to use instrument disinfectants
with proven effectiveness, such as those listed by the
VAH [8]. If a validated machine-reprocessing method is
available, manual reprocessing of semi-critical and critical
MDs requires proof of equivalent performance to the
machine method [1].
In Germany, TVUS are currently reprocessed either
manually with wipes or using automated methods, both
required as high-level disinfection [1], [9]. An economic
analysis of both methods was necessary to verify the
common perception that manual reprocessing is more
cost-effective. Since no manual wipe method has been
validated despite national legal requirements since 2002,
only the costs of the reprocessing process, including
material costs, could be determined for manual repro-
cessing. In contrast, the costs for type testing of the ma-
chine method are included in the purchase price. For the
selected device for the economic analysis, the manufac-
turer states that no validation after installation is required.
A survey was conducted to determine the current repro-
cessing practice for TVUS.
Method
Survey
The survey was conducted as a paper-pencil question-
naire sent to gynecology and obstetrics practices (ran-
domly selected) and as an online version, anonymously
and voluntarily, with written consent. The survey could
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be completed in about 5 minutes. Participants were in-
formed about the purpose, the fact that it was voluntary,
the opportunity to ask questions, and data handling. The
online survey was implemented using the “Unipark” sur-
vey tool (Questback GmbH, https://www.unipark.com)
and shared with the German Society for Gynecology and
Obstetrics e.V., the German In-Vitro-Fertilization Register,
and the German Society for Ultrasound in Medicine. Due
to the low response rate, an interview contribution was
initiated in the journal “Hospital and Management” to
motivate further participation in the online survey. The
questionnaire (see Attachment 1) was tested for compre-
hensibility with three female and three male experts in
the field of gynecology and obstetrics and adjusted after
validation.
In addition to asking whether TVUS was reprocessed
manually or using machines, information on process
design, including known recommendation bases, and the
implementation of hygiene in the work environment was
requested.
Economic analysis
Examined reprocessing methods
Two ready-to-use (rtu) disinfection wipes (methods A and
B), a wipe on which the disinfection solution is applied
immediately before use (method C), a 3-wipe system for
cleaning, disinfection, and final re-cleaning (method D),
and an automated chemothermal disinfection method
using hydrogen peroxide as a biocide (method E) were
analyzed (Table 1). The latter includes manual cleaning,
chemothermal disinfection, machine drying, and digital
documentation of critical process parameters. Methods
A–D are recommended by the manufacturer for repro-
cessing various ultrasound probes, while method E is re-
commended only for TVUS. All methods were used accord-
ing to the manufacturer’s instructions.
The economic analysis simulated manual and automated
reprocessing in a room of the Department of Obstetrics
and Gynecology at the University Medicine Greifswald,
where the automated reprocessing method was installed.
In methods A (Cleanisept®Wipes forte; Dr. Schumacher
GmbH, Malsfeld, Germany) and B (Incidin®OxyWipe S
Desinfektionstücher; Ecolab Deutschland GmbH, Wallis-
ellen; Germany), a wipe soaked with disinfectant from a
bulk pack is used. In method C (Tristel Duo®; Tristel GmbH
Berlin, Germany), the wipe is soaked with the disinfectant
immediately before use. Method D (Tristel Trio®Wipes
System; Tristel GmbH, Berlin, Germany) is a 3-wipe system
consisting of a separate wipe for cleaning, disinfection,
and final cleaning/drying. Each component allows docu-
mentation through a protocol book label with LOT number
and expiration date for the three steps until approval by
the reprocessing personnel. Documentation is possible,
but without critical process parameters. In method E
(Trophon2®; Nanosonics Ltd., Europe GmbH, Hamburg,
Germany), disinfection is performed in a chamber at a
minimum of 56°C with 35% hydrogen peroxide vapor
(cycle duration including drying: 7 minutes). Pre-cleaning
and cleaning are done with a Cleaning Wipe®and vali-
dated by checking the residual protein content. After the
disinfection cycle, the user is prompted to check if the
probe is dry. If not, it must be dried with a Drying Wipe®.
AcuTrace®enables digital traceability of the probe and
user identification using RFID technology. Internal sensors
and chemical indicators ensure quality by monitoring
process parameters such as time, temperature, and
dosage. The user receives the validation report in both
digital and analog form, providing process documentation
and the basis for subsequent parametric approval.
Economic analysis
For manual wipe systems, the same process steps de-
tailed in the recommendation of the Commission for
Hospital Hygiene and Infection Prevention at the Robert-
Koch Institute Berlin (KRINKO) and the Federal Institute
for Drugs and Medical Devices (BfArM) [2] were always
simulated to standardize time measurements (Table 2).
Intermediate rinsing was omitted, as manufacturers
stated that disinfection was adequate without it.
The wiping technique was standardized, starting with pre-
cleaning until visible cleanliness of TVUS prepared with
ultrasound gel, followed by cleaning and disinfection as
per manufacturer’s instructions, until the entire TVUS in-
cluding the handle are visible wet. Although not specified
by the manufacturer, cloths were wrung out or foam was
applied to indentations and cleaned with cotton swabs
for best cleaning and disinfection results (Figure 1).
The reprocessing procedure for the (semi-)automated
method (E) was similarly standardized (Table 3). For the
(semi-)automated process, the working path and disposal
of consumables were included in the time measurement.
Manual cleaning of indentations with cotton swabs was
omitted, as sufficient gel residue removal with a cleaning
cloth for successful disinfection has been described [10].
No working time was calculated for digital documentation.
For printout documentation, the time taken by the printer
and the time the responsible person needed to attach
the printout to the TVUS cover were measured.
Time measurements were conducted with a calibrated
stopwatch. Each reprocessing step was performed ten
times to calculate the average working time. Active and
passive times were distinguished, i.e., exposure time of
disinfectants and glove disposal time or machine cycle
time. The probe was always covered with a protective
sheath and prepared with ultrasound gel to simulate a
practical scenario.
Personnel costs for the time spent reprocessing were
calculated for nurses (pay grade KR 7, level 3), doctors
(pay grade Ä2, specialist), and medical assistants (MFA)
based on the collective bargaining agreement for public
service in the federal states (TV-L) and the salary tariff
agreement for MFA/nurse assistants (§ 3). No above-
tariff wage agreements were considered. Personnel costs
per reprocessing were calculated by multiplying the
working time with the personnel costs.
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Table 1: Characteristics of methods selected for economic analysis
Table 2: Standardized procedure for manual reprocessing (methods A–D)
Figure 1: Indentations on the probe
Material costs were determined based on specialist trade
prices and manufacturer list prices (as of February 2021).
Prices are dynamic and vary significantly depending on
whether materials are procured from individual traders
or through the purchasing department of a university
clinic. Prices for consumables, disinfectants, operating
costs, and device prices are net prices from the specified
suppliers or manufacturers.
One-time acquisition costs such as device or operating
costs were allocated over a usage period of five or ten
years. This also applies to the costs of validations and
maintenance of the automated reprocessing system. A
usage period of one year was set for the protective
glasses needed for manual reprocessing.
Energy costs were calculated with a net price of €0.23
per kilowatt-hour (kWh).
Process costs for the automated reprocessing method
were calculated assuming ten reprocessing cycles per
day on 256 working days, resulting in 2,560 applications
per year.
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Table 3: Standardized procedure for automated reprocessing (method E)
Finally, personnel, material, and total costs per repro-
cessing were determined.
Results
Survey
There was no response to the version distributed as online
link in the “Unipark” survey tool or to direct inquiries to
gynecological societies. Following postal distribution of
the paper-pencil version, 19 participants responded.
16 facilities took part in the online survey in the magazine
Krankenhaus und Management. Thus, 35 questionnaires
from 25 hospitals and 10 medical practices included in
the evaluation.
Thirty-three (33) participants used disinfection wipe pro-
cedures for TVUS reprocessing. Immersion disinfection
and an automated method were each used once. The
main reason for choosing manual procedures was the
short process duration (n=28), followed by the probe
manufacturer's recommendation (n=15) and lower costs
(n=7). Documentation and legal security were cited as
reasons for automated reprocessing.
Manual reprocessing revealed the following deficiencies:
No designated person for reprocessing approval (n=23),
no batch number assignment (n=22), no documentation
of process parameter measurements with at least 5-year
retention (n=21), no cleaning after wipe disinfection
(n=16), no approval decision (n=13), no additional con-
tamination removal, no visual inspection after repro-
cessing, and no use of VAH-listed wipes for disinfection
(n=3 each), and no removal of gel residues with a dry
cloth after removing the protective cover (n=2).
Deficiencies in knowledge of the required effect spectrum
were indicated: bactericidal (n=32), fungicidal (n=25),
levurocidal (n=23), mycobactericidal (n=17), and tuber-
culocidal (n=12). Instead of virucidal (e.g., effective
against Papovaviruses), four times limited virucidal and
six times limited virucidal Plus were indicated as required.
Although sporicidal effectiveness is not required, it was
indicated 21 times as required.
In 26 institutions, no residual protein determination was
performed after reprocessing. Six institutions used a
commercial swab test, three sent the test to a laboratory.
Testing intervals were monthly (n=4), quarterly (n=1),
semi-annually (n=3), or annually (n=1).
The ultrasound (US) probe was reprocessed after each
use. However, hand contact surfaces such as the key-
board and handle were only disinfected daily after the
last examination in 13 practices. The US gel bottle was
disinfected after each use in ten practices, in the remain-
ing practices only daily after the last use. Only five re-
spondents disinfected the US device, including cable and
plug, after each use. In 23 practices, this was done daily
after the last examination, and weekly in seven practices.
In 18 institutions, no disinfection of the US device was
performed before the first use of the day, 13 practices
disinfected the entire US device including cursor and
keyboard, and in four practices, only the probe was disin-
fected. The majority (n=23) reported daily disinfection of
all work surfaces.
Hand antisepsis was reported as follows: before each
examination (n=30), after each examination (n=27), upon
entering the examination room (n=12), and at the end of
the work shift (n=1).
In 28 institutions, the seat was covered with paper, which
was changed after each patient in 27 institutions and
daily in one institution. In five institutions, a wipe disinfec-
tion was performed instead of a cover after each patient.
In two institutions, a textile cover was used, changed
daily.
The joint recommendation of the KRINKO/BfArM on the
hygiene requirements for reprocessing medical devices
[2], which is the basis for every reprocessing, was only
known to 18 institutions. Thirteen (13) institutions fol-
lowed the hygiene recommendations in sonography and
endosonography of the German Society for Ultrasound
in Medicine [11].
Economic analysis
In total active and passive time, the automated method
E was the shortest (14.8 min), method B the longest
(23.9 min) (Figure 2).
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Figure 2: Total process time for reprocessing
In Figure 3, the processing time is broken down into pre-
cleaning, cleaning, disinfection, and post-treatment. In
the automated method, the disinfection duration was
longest except for method B; the shorter times for
cleaning and post-treatment led to the overall shorter
time. Pre-cleaning and cleaning are combined in the
machine method (see p. 19 and p. 24 [12]). TheCleaning
Wipe®replaces pre-cleaning, and a manual disinfection
wipe was used before chamber disinfection. Thus, addi-
tional wipe disinfection was performed before actual
chamber disinfection.
Personnel costs per reprocessing depend on the profes-
sional group performing the reprocessing. Regardless of
the professional group, personnel costs were lowest for
the automated method (Figure 4).
Material costs per reprocessing were highest for
method D. For the automated method E, costs depend
on whether a 5 or 10-year usage period is assumed
(Table 4).
Table 4: Material costs per reprocessing
Concerning total personnel and material costs, methods
A and B were significantly less expensive than methods
C, D, and E, regardless of whether costs were cumulated
over one, five, or ten years (Figure 5).
Due to the extensive measurements and calculations
(30 pages), they are available upon request or in the ap-
pendix of the dissertation upon which this paper is based
[12].
Discussion
Method
This survey aimed to provide an overview of the current
reprocessing situation in Germany. It was important not
to suggest answers to the respondents, which is why
specific actions during disinfection were queried rather
than process evaluations.
The questionnaire revealed several methodological
weaknesses in hindsight. Strict anonymity prevented
questions about the professional field. Thus, it remained
unclear whether a specialist doctor or a medical assis-
tant/nurse filled out the survey. The paper-pencil format
was less appealing than the online tool, possibly contri-
buting to the initial low response rate. Some question-
naires contained multiple answers due to ambiguous
questioning. Additionally, it would have been insightful
to know how respondents informed themselves about
the current reprocessing situation and which recommen-
dations they followed.
The economic analysis simulated reprocessing in a room
of the Department of Obstetrics and Gynecology at the
University Medicine Greifswald, where the automated
reprocessing method was installed. The standardization
of measurements by taking the same paths and using a
calibrated clock makes the time measurements realistic,
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Figure 3: Time duration of reprocessing steps
Figure 4: Personnel costs per reprocessing
but they are not directly transferable to everyday practice.
To achieve complete wetting of the probe with wipes, in-
dentations and grooves were wetted separately with a
cotton swab. The time for this is not typically expended
in practice.
The omission of manual cleaning of indentations and
grooves before automated disinfection with hydrogen
peroxide is critical, as residues such as protein, blood
catalase, and salts can make disinfection success dubi-
ous [13]. This time effort should have been included in
the economic analysis.
The different yield of various wipe products concerning
the amount of disinfectant released also impacted the
process duration, requiring a varying number of wipes to
achieve complete wetting of the probe.
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Figure 5: Total reprocessing costs cumulated for one, five, and ten years (for method E, device costs are amortized over 10
years)
Personnel costs were calculated based on three years of
professional experience, which allows only an indicative
calculation. Material costs could only be estimated, as
specialist trade and manufacturer list prices vary and
change dynamically.
Although the calculated process costs provide only an
orientation, the costs of the reprocessing methods can
be compared due to the similar methodological approach.
In the cost calculation of manual methods, the effort for
initial validation could not be considered due to the lack
of experience. This also applies to the follow-up costs
associated with validation documentation and periodic
residual protein determination.
Results
Survey
The low participation in the survey likely reflects the time
overload in daily practice, possibly overlapped by low in-
terest in the topic. Knowledge deficits about TVUS repro-
cessing may also play a role,as evidenced by nine incom-
plete questionnaires.
Unfortunately, the sample size of 35 allows only an indi-
cative assessment. Additionally, 25 of the participants
were from hospitals, making the survey non-representa-
tive for smaller practices.
The survey revealed that almost exclusively wipe proce-
dures were used, which have not been validated, contrary
to the Medical Devices Operator Ordinance [1], and partly
did not cover the recommended effect spectrum [1]. The
main reason for choosing wipe disinfection was the short
process duration. However, the economic analysis showed
the shortest process duration for automated reprocessing.
Costs were also cited as a reason for choosing manual
methods. While this is true for acquisition costs, the
comparison of cumulative costs for one, five, and ten
years showed that automated reprocessing was cheaper
than using two of the wipe systems. Two other wipe sys-
tems were less expensive than the automated method,
but it remains unclear what additional costs arise from
the required validation and the time effort when the val-
idated reprocessing process is routinely performed based
on an SOP.
Economic Analysis
The automated reprocessing method had the shortest
process duration overall. Differences in the generally
similar working times for manual reprocessing resulted
from the different handling or yield of disinfectant solution
from the wipes and different exposure times. Since no
drastic cost differences were found between the auto-
mated and two manual reprocessing methods with spe-
cified steps, and even two more wipe methods were less
expensive but susceptible to additional costs from valida-
tion, a general preference for automated reprocessing
can be concluded due to higher procedural safety from
better standardization. After using a ready-to-use wipe
with microbicidal, levurocidal, sporicidal, and virucidal
effectiveness, representatives of vaginal, pharyngeal, and
skin flora were detected on TVUS in 10.6% of samples
[14]. Using the same 3-wipe system in a cardiology unit
caused two outbreaks by the same clone and a third
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Kiefner et al.: Cost analysis of machine and manual reprocessing of ...
outbreak by a new clone of an extended-spectrum beta-
lactamase-producing Enterobacter cloacae after transeso-
phageal echocardiography [15]. After switching to auto-
mated reprocessing, the outbreak ended.
Validated reprocessing guidelines and quality-assured
implementation are crucial, as risk assessments show.
A computer simulation calculated the infection risk from
contaminated TVUS at 1–6% depending on the pathogen
[16]. The Scottish National Health Services analyzed the
infection risk after endocavitary ultrasound examinations
from 2010–2016. The post-interventional infection risk
from TVUS was significantly higher (factor 141) for positive
microbiological findings and antibiotic prescriptions
compared to a reference population of other hospitalized
gynecology patients. During this period, there was no
standardized work instruction for reprocessing ultrasound
probes in Scotland, leading the authors to emphasize the
need for standardized quality-controlled reprocessing
guidelines [17]. Due to higher procedural safety, the
Charité University Medicine Berlin received second place
for the German Patient Safety Award 2020 for introducing
the selected automated method for economic analysis
[18].
The knowledge deficits from the survey on quality-assured
reprocessing of TVUS highlight the need to convey basic
reprocessing knowledge during medical school. The im-
portance of consolidating this knowledge during further
training, such as in curricula for hygiene officers, should
be emphasized. Critically, the indicated deficiencies in
disinfecting the ultrasound device, including the gel bottle,
cable, and plug, are concerning, since Staphylococcus
aureus and Pseudomonas putida were detected on TVUS
keyboards, and Acinetobacter spp., Enterococcus (E.)
faecium, and E. faecalis were found on ultrasound devices
[19]. An environmental study showed that not only the
ultrasound probe was contaminated with blood and bac-
teria (57% and 46%) but also the ultrasound housing
(75% and 75%), keyboard (62% and 50%), and most
heavily the ultrasound cable (88% and 62%) [20].
Since manufacturer information was sometimes incom-
plete or incorrect, there is also a need for improvement
here.
Besides hygiene safety and, subsequently, economic ef-
ficiency, resource consumption must be minimized in any
disinfection method. The automated method likely has
lower resource consumption for the following reasons:
No waste of plastic packaging for wipes, no used disin-
fectant wipes waste, no environmental impact from the
immediate complete breakdown of hydrogen peroxide
into water and oxygen after disinfection, lower resource
usage in producing hydrogen peroxide compared to qua-
ternary ammonium compounds combined with NaOH,
inorganic peroxides, peracetic acid, and chlorine dioxide,
and no additional cleaning wipe needed to remove disin-
fectant residues after wipe disinfection.
Conclusions
The lack of knowledge of national legal requirements and
recommendations for reprocessing MDs is a reason why
reprocessing principles were often not followed. Since
the practice owner or the medical director in hospitals is
responsible for reprocessing MDs, ensuring validated
reprocessing of MDs is imperative to ensure patient
safety.
Limitations
Before simulating automated disinfection, manual
cleaning of the probe’s indentation was omitted as it was
not required by the manufacturer’s instructions. Since
the effectiveness of hydrogen peroxide is significantly
affected by residues such as protein, salts, and ultra-
sound gel, this cleaning step is considered essential in
practice [13]. The time required for this is 9.2 s and does
not significantly affect the economic analysis.
Notes
Competing interests
The authors declare that they have no competing in-
terests.
Author’s ORCID
Axel Kramer: 0000-0003-4193-2149
Attachments
Available from https://doi.org/10.3205/dgkh000511
1. Attachment1_dgkh000511.pdf (101 KB)
Questionnaire
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Corresponding author:
Prof. em. Dr. med. habil. Axel Kramer
Institute of Hygiene and Environmental Medicine,
University Medicine Greifswald,
Ferdinand-Sauerbruch-Str., 17475 Greifswald, Germany,
Phone: +49 3834 864832
axel.kramer@med.uni-greifswald.de
Please cite as
Kiefner D, Benkhai H, Lemanski S, Thanheiser M, Kramer A. Cost
analysis of machine and manual reprocessing of transvaginal ultrasound
probes. GMS Hyg Infect Control. 2024;19:Doc56.
DOI: 10.3205/dgkh000511, URN: urn:nbn:de:0183-dgkh0005118
This article is freely available from
https://doi.org/10.3205/dgkh000511
Published:
2024-11-05
Copyright
©2024 Kiefner et al. This is an Open Access article distributed under
the terms of the Creative Commons Attribution 4.0 License. See license
information at http://creativecommons.org/licenses/by/4.0/.
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Kiefner et al.: Cost analysis of machine and manual reprocessing of ...
