Reprocessing of semi-critical medical devices

Medical devices like endoscopes or transvaginal ultrasonic probes come into direct contact with mucous membranes or pathologically altered skin and, thus, are classified as “semi-critical”. Studies have shown that the prevalence of contaminated transvaginal ultrasound probes is about 14%, emphasising the importance of correct reprocessing of this kind of medical devices [1-3]. To successfully reduce the risk of transmitting infections, the disinfection as part of the reprocessing should be effective against bacteria, viruses, yeasts, and fungi.

Legal requirements (Germany)

In Germany, reprocessing of semi-critical medical devices is governed by the “Medizinprodukte-Betreiberverordnung” (MPBetreibV) which incorporates recommendations from the “Kommission für Krankenhaushygiene und Infektionsprävention” (KRINKO) and the “Bundesinstitut für Arzneimittel und Medizinprodukte” (BfArM) [4]. According to §8 (1) MPBetreibV, the reprocessing of semi-critical medical devices must be performed with an adequate and validated method so that safety and health of patients, users, and third parties is ensured [4].

The above-mentioned institutes recommend the application of automated procedures for cleaning and disinfection since they can be validated [5]. In a statement of the Robert Koch Institute from November 2020, this opinion was extended: to the knowledge of the board members, a manually performed reprocessing of semi-critical medical devices by a wipe disinfection cannot be validated [6]. In October 2021, the state authorities responsible for medical devices and the BfArM have agreed on this statement [7].

Alternatives to automated reprocessing

Certain medical devices cannot undergo automated reprocessing procedures due to constructional restrictions. In these cases, disinfection by immersion is recommended [7]. For transvaginal ultrasound probes, Korsolex®basic or Korsolex®extra can be used. After immersion disinfection, removal of residual disinfectant by sufficient rinsing is important as well as storing in a way which excludes re-contamination. Moreover, manufacturers’ instructions regarding the product’s water permeability must be considered, thus, maybe not the whole medical device can be immersed.

The HARTMANN SCIENCE CENTER in cooperation with Dr. Brill + Partner GmbH, Institute for Hygiene and Microbiology, has developed a method for reprocessing of transvaginal ultrasound probes based on wipe disinfection with Mikrobac® Virucidal Tissues [8]. This procedure allows for an effective reprocessing as soon as it is validated on-site and in accordance with the risk management of the facility.

Responsibility of manufacturers

In reprocessing of medical devices, moving parts like the air or water valves of endoscopes pose a special challenge. A study from 2014 showed that about 87% of the investigated valves were contaminated [9]. During the application of endoscopes, the valves are moved up and down constantly. “In the course of cleaning and disinfection, these valves must be moved in a similar manner to cover all surfaces. This might be possible for a skilled user during brush precleaning, however, in immersion disinfection exposure times need to be met and this is not applicable anymore”, says Prof. Dr. Heike Martiny (Charité-Universitätsmedizin Berlin, Technische Hygiene) in an interview (06 November 2019).

Even Automated Endoscope Reprocessors (ARE) do not offer complete safety: “For this kind of automated reprocessing, it cannot be assured that all surfaces in the valves are exposed to the disinfectant for a sufficiently long time”, Prof. Martiny is warning. “According to the guidelines, valves are part of the endoscope and, after being cleaned thoroughly using brushes, should preferably be reprocessed in an AER in a validated procedure.”

The operator is responsible for the reprocessing of semi-critical medical devices; however, Prof. Martiny calls for more responsibility of the manufacturers by providing detailed instructions for reprocessing of the devices. “Elaborated instructions for the following measures must be available: First use on site, preparation before cleaning, cleaning, disinfection, drying, inspection and maintenance, packaging, sterilisation, storage, and transport.” In the ISO17664 detailed requirements for this information supplied by the manufacturers are given.

In case of ambiguities, Prof. Martiny recommends disposable valves: “Using disposable valves is the safest measure for prevention of transmitting infections over using insufficiently reprocessed and thus potentially contaminated valves. By now, there are disposable valves for several types of endoscopes on the market. Their application saves time and can increase the efficacy of the reprocessing procedure as a whole.”

We thank Prof. Matiny for the interview (translated from German by HARTMANN SCIENCE CENTER).

References:

1. Leroy S (2013) J Hosp Infect 83(2):99-106.

2. David C et al. (2019) Isr Med Assoc J 21(1):45-49.

3. Westerway SC et al (2017) Ultrasound Med Biol 43(2):421-426.

4. Medizinprodukte-Betreiberverordnung in der Fassung der Bekanntmachung vom 21. August 2002 (BGBl. I S. 3396), die zuletzt durch Artikel 7 der Verordnung vom 21. April 2021 (BGBl. I S. 833) geändert worden ist.

5. KRINKO (2012) Anforderungen an die Hygiene bei der Aufbereitung von Medizinprodukten. Bundesgesundheitsbl 55:1244–1310.

6. RKI, Aufbereitung von Medizinprodukten: Häufig gestellte Fragen und Antworten, https://www.rki.de/DE/Content/Infekt/Krankenhaushygiene/Aufb_MedProd/Aufb_MedProd_node.html (accessed on 14.04.2022)

7. RKI, Epid Bull 2021;44:13 -15, doi 10.25646/9185.

8. unveröffentlichter Bericht (2020) – Daten bei der BODE Chemie.

9. Riebe O et al. (2014) Endo-Praxis 30(04):174-179.