Sterilization Monitoring

Process challenge devices (PCD) have been used for steam sterilization for years as a requirement for implant release. Moreover, many facilities have adopted using a PCD with every load monitoring (ELM) for routine load release. In this issue of “Tips for Success” we will explore the rationale in using a PCD in every low temperature sterilization cycle.

Regulation Process Challenge Device (PCD) Biological Indicator (BI)
ANSI/AAMI ST58:2013 (R) 2018 Item designed to constitute a defined resistance to a sterilization process and used to assess performance of the process. Test system containing viable microorganisms providing a defined resistance to a specified sterilization process.
ANSI/AAMI ST58:2013 (R) 2018 Item designed to constitute a defined resistance to a sterilization process and used to assess performance of the process. Test system containing viable microorganisms providing a defined resistance to a specified sterilization process.
ANSI/AAMI ST58:2013 (R) 2018 A PCD is a device used to assess the effective performance of a sterilization process by providing a challenge to the process that is equal to or greater than the challenge posed by the most difficult-to-sterilize item routinely processed. Biological sterilization process indicator device intended for use by a health care provider to accompany products being sterilized through a sterilization procedure and to monitor adequacy of sterilization.
ANSI/AAMI ST58:2013 (R) 2018 Item designed to simulate products to be sterilized and to constitute a defined challenge to the sterilization process and used to assess the effective performance of the process. Microbiological test system providing a defined resistance to a specified sterilization process.

What are the process monitors used for low temperature sterilization and why are they important?

Association for the Advancement of Medical Instrumentation (AAMI) ST58(R)2018 states:

  1. Physical: Displays, digital printouts, gauges
    • “Physical monitoring provides real-time assessment of the sterilization cycle conditions and provides permanent records by means of chart recordings or digital printouts. Physical monitors are needed to detect malfunctions as soon as possible, so that appropriate corrective actions can be taken in the event of failures” (p. 51).
  2. Physical: Displays, digital printouts, gauges
    • “Chemical indicators should be used in conjunction with physical monitors and Bis to demonstrate the efficacy of the sterilization process” (p. 51)
  3. Biological indicators spores: BIs, PCDs
    • Biological indicators are intended to demonstrate whether or not the conditions were adequate to achieve sterilization. A negative BI does not prove that all items in the load are sterile or that all were exposed to adequate sterilization” (p. 3).
    • “PCDs are challenge test packs containing a BI or BI and a CI. A PCD is used to assess the effective performance of a sterilization process by providing a challenge to the process that is equal to or greater than the challenge posed by the most difficult item routinely processed” (p. 53).

How often should a PCD be used for low temperature sterilization?

Two professional organizations that provide guidelines for sterilization of medical devices provide recommendations for how often a PCD should be used in low temperature sterilization.

  • AAMI states in ST58 that “a PCD with the appropriate BI should be used at least daily, but preferably in every sterilization cycle.”
  • AORN in their Guidelines for Perioperative Practice states -“Routine sterilizer efficacy monitoring should be performed every day for each sterilization cycle used (e.g. standard, advanced, lumen, non-lumen), preferably with each load.”

WHY should a PCD for Low Temperature Sterilization be used in every cycle?

  • PCDs are constructed to test worst case sterilization load. (ANSI/AAMI ST58:2013 (R) 2018)
  • PCDs can be used for periodic testing of the sterilizer. (ANSI/AAMI ST58:2013 (R) 2018)
  • Using a PCD in every load meets AAMI guidelines and AORN recommendations.
  • Quick readout PCDs allow the sterilized load to be quarantined prior to reading the BI results.
  • There are three process monitors for low temperature sterilization: Physical, chemical and biological. Confirming results of all three for every cycle provides the greatest assurance of sterility. (ANSI/AAMI ST58:2013 (R) 2018)

Key Take aways

Historically, biological indicator options for low temperature sterilization have been limited and PCD options unavailable. Technology has progressed and access to a PCD for every sterilization load that is processed is attainable allowing access to the same standard of care for all patients.

References

  1. American National Standard/Association for the Advancement of Medical Instrumentation (ANSI/AAMI). 2013(2018). ST58:2013/(R)2018. Chemical sterilization and high-level disinfection in health care facilities. pp. 3, 51, 53.

  2. American National Standard/Association for the Advancement of Medical Instrumentation (ANSI/AAMI). 2017. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities. p. 81.
    Association of Perioperative Registered Nursing (AORN). 2019. Guidelines for Perioperative Practice. Denver, CO. AORN p. 992.

  3. Food and Drug Administration (FDA). October 4, 2017. Guidance for Industry and FDA Staff. Biological Indicator (BI) Premarket Notification 510k Submissions. Rockville, MD. pp. 3-5. Retrieved august 2, 2020 at http://www.fda.gov.

  4. Danish Standards Association. 2017. Sterilization of Health Care Products-Biological Indicator Part 1-General Requirements (ISO 11138- 1:2017). p. 3. Denne Publication.