Maintaining Quality Control With “Table-Top” Sterilizers Part II

In Part I of this blog  we pointed out that over the past 30 years, there has been a very significant increase in the number of outpatient surgical procedures. More specifically, outpatient procedures surpassed 54 million last year and is now approaching the number of procedures done in hospitals.1 Given this tremendous growth, and as was discussed in Part I, numerous healthcare accreditation bodies and regulatory agencies are taking an ever expanding scrutiny of these facilities and their reprocessing activities. One area that is receiving extra attention in these facilities is ‘table-top’ sterilizers. In Part II of this blog we’ll look at the steps that need to be taken to ensure the proper operation and maintenance of table-top sterilizers. The first step that needs to be taken if you are using table-top steam sterilizers is to routinely monitor the sterilizers utilizing a variety of monitoring tools. These monitoring tools should include process challenge devices (PCDs), chemical indicators (CIs), biological indicators (BIs) and physical monitors. Personnel operating table-top steam sterilizers should be consciously deciding whether or not to release each load based on the results of these various monitoring tools. When it comes to physical monitors, AAMI ST79, Section 13.5.1 states: “Sterilizers that do not have recording devices should not be used, with the exception of sterilizers used together with accessory recording devices or printouts.”2 Printouts, charts and gauges on the sterilizer that provide real-time measurements of time, temperature, and pressure are the physical monitors necessary to ensure sterility on each cycle. Without these physical monitors it is impossible for the operator to know if the correct cycle was selected and whether or not the correct parameters were delivered. The operator should read and initial the cycle printout to verify that the correct cycle was selected and the cycle ran properly after every cycle. Chemical indicators (CIs) allow personnel to distinguish processed loads from unprocessed loads with a simple glance. The most common external CI is steam sterilization indicator tape that changes color if all of the sterilization cycle parameters were met. AAMI ST79 Section 13.5.2.2.1 recommends that all packages should have a Type 1 external CI unless the internal CI is visible. If the CI has not changed color after the sterilization cycle is complete, that load must not be used and you must investigate the cause of the failure. In addition to external Cis, you should use internal CIs as well to verify that steam penetrated to the location of the instruments inside each package. AAMI ST79 Section 13.5.2.2.2 recommends, “One or more internal chemical indicators should be placed within each package, tray, or rigid container. These indicators can be any type (Type 3, 4, 5, or 6) but preferably a Type 5 or Type 6 indicator because these types of CIs provide the user with more information on the critical steam sterilization parameters.”3 As is the case with external CIs, if the internal CI does not show an acceptable result, the items in the package should not be used and the cause of the failure investigated. In addition to external and internal CIs, you need to use biological indicators (BIs) as well. Bis come with a large population of live spores which are highly resistant to the temperature and pressure encountered during the sterilization process. With table-top steam sterilizers, the use of BIs containing Geobacillus stearothermophilus spores is recommended. AAMI ST79 Section 13.5.3.1 states, “Biological indicators are the only sterilization process monitoring device that provides a direct measure of the lethality of the sterilization process.”4 So what should you do if any of your various monitoring tools indicate a failed sterilization cycle? AAMI ST79 provides guidance in Section 13.7.5 on the actions you need to take when investigating a sterilization process failure. This section states, “If the cause of the failure is not immediately identified, the load should be quarantined, and all loads back to the last negative BI should be recalled. Items in these loads should be retrieved, if possible, and reprocessed (see 13.7.5.2). The sterilizer in question should be taken out of service until the cause of the failure is identified and corrected.”5 To ensure consistent quality control with your sterilizers, you must document each and every load. Specifically, each tray or package must be traceable to the load that it was sterilized in. Specific traceability can be accomplished by labeling each tray or package with a lot control number including the sterilization date, the sterilizer number, and the load number. AAMI ST79 recommends that the following information be recorded and maintained for each sterilization cycle:

1. the lot number;
2. the specific contents of the lot or load;
3. the exposure time and temperature, if not provided on the sterilizer recording chart;
4. the name or initials of the operator;
5. the results of biological testing, if applicable;
6. the results of Bowie-Dick testing, if applicable;
7. the response of the CI placed in the BI PCD, if applicable; and
8. any reports of inconclusive or nonresponsive CIs found later in the load.6

Section 12.7 of AAMI ST79 also recommends maintaining a maintenance record for each sterilizer. You need to consult the sterilizer instruction manual for guidance on routine care, preventive maintenance and calibration of the sterilizer. Any reusable medical device, especially surgical instruments, must be sterilized before being returned to use. Table-top steam sterilizers play a key role in reusable device sterilization in office-based practices, outpatient clinics and ambulatory surgery centers. As we’ve shown in this two-part blog series, AAMI ST79 provides guidance on both testing and also on documenting the test results for table-top steam sterilizers used in these settings. 1 https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/outpatient-surgery 2 Association for the Advancement of Medical Instrumentation. Comprehensive guide to steam sterilization and sterility assurance in health care facilities. ANSI/AAMI ST79:2017. Arlington (VA): AAMI, 2017. 3 Op. Cite. 4 Op. Cite. 5 Op. Cite. 6 Op. Cite.