The Importance of Using Validated Medical Devices and Consumables

The general requirements for the characterization of a sterilizing agent and the development, validation and routine control of a sterilization process are described in the standard ISO 14937.1 Validation, the process that certifies and documents that a particular procedure meets the minimum requirements for which it was designed, is essential for all sterilization processes.2 Medical device manufacturers (MDMs) and sterilizer manufacturers (SMs) should therefore validate that sterilization processes provide a sterilization assurance level (SAL) of 10-6 for all relevant medical devices (MDs).2, 3 This sterility assurance is vital for infection prevention, specifically the prevention of healthcare associated infections, which are often attributed to the inadequate reprocessing of MDs.3, 4

Sterility assurance

For every sterilization cycle, it is critical to ensure that each MD has been adequately reprocessed. Failures in reprocessing increase the risk of using a contaminated MD during a subsequent procedure. The use of a contaminated MD can compromise patient safety by increasing the risk of infection transmission; after the use of a Klebsiella pneumoniae-contaminated endoscope, 17 out of 68 of the exposed patients subsequently developed urosepsis.5 However, a considerable proportion of these healthcare associated infections, including surgical site infections, are considered to be preventable, highlighting the need for sterility assurance to maximise patient safety.3, 4

To confirm that MDs can be adequately sterilized with a particular sterilization cycle and in a particular sterilizer, rigorous testing of each instrument is required, in collaboration with the SM and MDM. Two sterilization cycles, even if using the same sterilant, use a distinct combination of various parameters to achieve sterility assurance (e.g., concentration, exposure time, temperature). This combination of parameters also varies depending on the device(s) being reprocessed.3 Therefore, given this variation, it is incorrect to assume that two sterilization cycles using the same sterilant both provide sterility assurance for a given MD. Such generalization risks inadequate sterilization, which can ultimately risk exposure to infection.3

In order to ensure sterility assurance for each MD, validation that a process supplies effective sterilization is required.3

Sterilization validation

The validation of a sterilization process consists of installation, operational and performance qualifications. These steps ensure that sterilization is in keeping with the validated specification, whilst providing a SAL of 10-6 for all MDs:2

  • Installation qualification: the process of documenting evidence that equipment has been installed in accordance with the specification
  • Operational qualification: the process of documenting evidence that equipment operates within pre-determined limits when used in accordance with the operating procedures
  • Performance qualification: the process of documenting evidence that operational procedures consistently perform in accordance with pre-determined criteria, yielding the produce that aligns with the specification

It is necessary to validate all stages of a sterilization process, including cleaning, inspection, wrapping, packages, loading and unloading.2 This is especially important at points where contamination may occur.Transportation of sterile devices should also be considered, with the Association of Perioperative Registered Nurses (AORN) and the German Society for Sterile Supply both recommending that sterile items are contained within a validated sterile barrier system.6, 7

To ensure that all MDs can undergo validated sterilization at all stages of reprocessing, responsibility must be shared between MDMs, SMs and health care professionals (HCPs). MDMs determine how each MD should be reprocessed in collaboration with the SM, who provide sterility assurance whilst ensuring material compatibility and functionality. Following validation, the method of reprocessing is confirmed by the MDM, who reflect this in the Instructions for Use. These instructions are followed by HCPs to ensure adequate reprocessing.3

The involvement of Advanced Sterilization Products (ASP) in sterility assurance

As an SM, ASP is pivotal to ensuring that MDs can be adequately sterilized.3 A growing number of countries are accepting the recently published ISO 22441 standard, which describes the requirements for the development, validation and routine control of low temperature hydrogen peroxide sterilization for MDs.1 ASP works directly with MDMs to perform rigorous instrument validation using STERRAD™ Systems, considering variations in real-world practices. Upon successful validation, devices are listed in the STERRAD™ Sterility Guide (SSG), a reference database of MDs which meet the sterility claims.8 To date, the SSG reports over 20,000 individually validated listings of MDs that are validated for use with STERRAD™ Systems, from over 100 manufacturers.8

Alongside their involvement in validation, ASP have also developed several consumables and accessories for sterilization. These consumables are the only ones fully validated by ASP for use in all STERRAD™ Systems:

  • APTIMAX™ Instrument Trays, a lightweight and durable option designed to encase surgical instruments for sterilization. Only STERRAD™ Instrument Mats and Holders have been validated for use with APTIMAX trays9
  • ASP Tyvek™ Pouches and Rolls with STERRAD™ Chemical Indicator strips, intended for the packaging of MDs that are to be sterilized, and the maintenance of their sterility until their next use10
  • STERRAD™ System cassettes, which contain a precise measurement of hydrogen peroxide solution, for use during low temperature hydrogen peroxide gas plasma sterilization11

To provide additional sterility assurance, the Association for the Advancement of Medical Instrumentation (AAMI), the professional organization which provides guidelines for the sterilization of MDs, recommends that every sterilization cycle should be monitored.13 The STERRAD VELOCITY™ Biological Indicator/Process Challenge Device (BI/PCD) can support this frequent monitoring and periodic testing of the sterilization conditions of STERRAD™ Systems:

  • The biological indicator system provides a fluorescent read out, which determines if conditions are adequate to achieve sterilization by confirming if a cycle successfully inactivated microorganisms in the BI ampule12,14
  • The process challenge device provides a challenge greater than or equal to the most challenging MD that requires sterilization, using spores that are difficult to target, to test the effectiveness of a sterilization cycle14

Combined, this fully integrated system can accurately assess the performance of sterilization procedures.

References

  1. British Standards Institution. Sterilization – regulatory requirements and supporting standards. Available from: https://pages.bsigroup.com/l/35972/2020-04-03/2cqy82j. Accessed 11/04/2023.

  2. World Health Organisation. Decontamination and reprocessing of medical devices for health-care facilities. 2016. Available from: https://apps.who.int/iris/handle/10665/250232. Accessed 26/01/2023.

  3. Advanced Sterilization Products. The Importance of Instrument Validation. AD-200105-01-CT_B-MDR.

  4. European Centre for Disease Prevention and Control. Healthcare-associated infections in intensive care units. 2015. Available from: https://www.ecdc.europa.eu/en/publications-data/healthcare-associated-infections-intensive-care-units-annual-epidemiological. Accessed 26/01/2023.

  5. Güler Y, Erbin A, Gozdas T. An outbreak of postoperative rapidly developing and multidrug-resistant Klebsiella pneumoniae urosepsis due to a contaminated ureteroscope. Folia Med (Plovdiv) 2022;64:401-407.

  6. Association for Perioperative Nurses. Guidelines for perioperative practice: sterilization. 2020. Available from: https://www.aornguidelines.org/guidelines/content?sectionid=173737535&view=book&expand=true. Accessed 26/01/2023.

  7. German Society for Sterile Supply. Guideline for validation of packaging processes according to ISO 11607-2. Available from: https://www.besdecon.net/media/318956/IS011607-2-Packaging-Validation.pdf. Accessed 26/01/2023.

  8. Advanced Sterilization Products. STERRADSterilityGuide.com.

  9. Advanced Sterilization Products. APTIMAX™ Instrument Trays: Instructions for Use. Available from: https://www.asp.com/en-gb/products/terminal-sterilization/aptimax-instrument-trays#section-5. Accessed 26/01/2023.

  10. Advanced Sterilization Products. Tyvek® Pouch with STERRAD™ Chemical Indicator (Heat Seal [125XX] and Self Seal [123XX]) Tyvek® Roll with STERRAD™ Chemical Indicator (124XX): Instructions for Use. Available from: https://www.asp.com/en-us/products/terminal-sterilization/tyvek-pouches#section-4. Accessed 26/01/2023.

  11. Advanced Sterilization Products. STERRAD NX™ Cassette: Instructions for Use. Available from: https://www.asp.com/en-gb/products/low-temperature-sterilization/sterrad-velocity-biological-indicator-system#section-3. Accessed 26/01/2023.

  12. Advanced Sterilization Products. STERRAD VELOCITY™ Biological Indicator/Process Challenge Device: Instructions for Use. Available from: https://www.asp.com/en-gb/products/low-temperature-sterilization/sterrad-velocity-biological-indicator-system#section-3. Accessed 26/01/2023

  13. Association for the Advancement of Medical Instrumentation. ANSI/AAMI ST58:2013/(R)2018 Chemical sterilization and high-level disinfection in health care facilities. 2018. Available from: https://webstore.ansi.org/standards/aami/ansiaamist582013r2018. Accessed 11/04/2023.

  14. Advanced Sterilization Products. STERRAD VELOCITY™ Biological Indicator/Process Challenge Device. Available from: https://www.asp.com/sites/default/files/pdf/Velocity/STERRAD%20Velocity%20PCD%20Brochure.pdf. Accessed 30/01/2023.

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