Here's a typical scenario in a biomed shop: a sterilizer has undergone service according to the manufacturer's recommendations and is ready to be placed back into use. A sterilizer cycle is run and the physical monitors are reviewed to ensure that all of the sterilization parameters are met. The biomed notifies the appropriate sterilization personnel that the unit is tested and ready for use. But wait—there may be more.
Additional testing, such as qualification testing, is required after sterilizer installation, relocation, and malfunctions as well as major sterilizer repairs or utility repairs. A major sterilizer repair is anything outside the scope of normal maintenance. Examples include weld repairs of the pressure vessel, door replacement, vacuum pump replacement, or rebuilds or upgrades of the controls. Qualification testing is not required for normal preventive repairs such as rebuilding of solenoid valves or the replacement of door gaskets. While the biomed may not be responsible for performing these additional tests, it is his or her responsibility to notify sterilization personnel of exactly what type of repair was performed.
In 2009, The Joint Commission's Comprehensive Manual of Accreditation for Hospitals required that the hospital conduct sterilizer performance testing and maintain all sterilizers. The records from this testing must be maintained. Biomedical equipment technicians do record and maintain the servicing they perform on the sterilizers, including the results from the physical monitors; however, the true performance indicator for a sterilizer is the biological indicator (BI). This testing is performed by the sterile processing technicians.
According ANSI/AAMI ST79:2006/A1:2008/A2:2009 —Comprehensive guide to steam sterilization and sterility assurance in health care facilities and ANSI/AAMI ST41:2008—Ethylene oxide sterilization in health care facilities: Safety and effectiveness, the sterilizer must undergo qualification testing using a BI in a process challenge device (PCD) to ensure that the sterilizer is functioning. ABI provides the only direct measure of the lethality of the sterilization process.
The type of BI used is determined by the sterilization process, as the BI must be resistant to that process. A BI PCD could be assembled at the healthcare facility or as a commercially available, disposable, preassembled challenge test pack. The composition of the PCD is described in both of the documents referenced above. A BI PCD always contains a biological indicator; it may also contain a Class 5 integrating indicator, which may provide early detection of a sterilizer failure.
Regardless of the type of sterilization, the BI is the definitive indicator. For steam sterilization, the spore used is Geobacillus stearothermophilus, while for ethylene oxide sterilization the spore used is Bacillus atrophaeus. The type of BI PCD may be dependent upon the sterilizer, but the test itself is a standard process and should be performed by the sterilizer operator. They are used to challenge the sterilization process and can detect sterilization failures that are not indicated on the physical monitors, such as failures associated with steam quality.
The testing procedures are defined in the following AAMI recommended practices:
ANSI/AAMI ST79:2006/A1:2008/A2:2009, section 10, Quality control.
ANSI/AAMI ST41:2008, section 10, Quality control.
Both documents describe the testing that should be performed after sterilizer malfunctions, relocation, and repair as “qualification testing.” Qualification testing guidance is explained in both documents under section 10.8, “Qualification tests.” This section details the process, types of sterilizers, and types of repairs it applies to. Both documents also address qualification testing under section 10.6.4, “Sterilization process failures.”
Different types of qualification methods are used, depending on the type of sterilizer and cycle. The testing always uses a BI and it may also include the use of a Bowie-Dick test, which is a sensitive and rapid means of detecting air leaks. Listed below are qualification tests required for common types of sterilizers.
Steam sterilizers larger than two cubic feet and flash sterilizers: A BI PCD is placed in an empty chamber in the most challenging area to sterilize. The appropriate cycle is run three times consecutively. The physical monitors and chemical indicators should show appropriate readings. The testing results from the BI PCD should show negative growth results. Dynamic air sterilizers are further challenged with Bowie-Dick tests for three consecutive cycles after the BI PCD cycles.
Steam table top sterilizers: A BI PCD is placed in a fully loaded sterilizer in an area that is least favorable to sterilization (items processed in these loads should be quarantined until the results are known). The appropriate cycle is run three times consecutively. The physical monitors and chemical indicators should show appropriate readings. The results from the BI PCD should show negative growth results.
Ethylene oxide sterilizers: After installation or relocation, one or more BI PCDs should be run for three consecutive cycles in a simulated load. The simulated load should contain additional PCDs without BIs, but not packaged patient care items. The load size will vary with the sterilizer size.
Ethylene oxide sterilizers after sterilization process failure: Monitor one cycle with a PCD that contains a biological and chemical indicator in a load similar in composition and density to the load exhibiting the sterilization failure. The load should be quarantined until the results of the biological monitor are known.
Ethylene oxide sterilizers after malfunctions and major repairs: A major repair is outside the scope of normal repairs, such as upgrading the controls or replacing the chamber door. Monitor three consecutive cycles with one or more PCDs containing a biological and chemical indicator in a load similar in composition and density to the load exhibiting the sterilization process failure. If items in the test load are to be used in patient care, the load should be quarantined until the biological results are known.
Ethylene oxide sterilizers after a redesign: One or more BI PCDs should be run in three consecutive half cycles in a simulated load. The simulated load should contain additional PCDs without BIs, not packaged patient care items. The load size will vary with the sterilizer size. Three additional full cycles are run using full exposure cycles in an otherwise empty chamber.
ST79, Comprehensive guide to steam sterilization and sterility assurance in health care facilities
Order Code: ST79 or ST79-PDF
Price/AAMI Member Price: $220/$110
ST41, Ethylene oxide sterilization in health care facilities: Safety and effectiveness
Order Code: ST41 or ST41-PDF
Price/AAMI Member Price: $200/$100
To order, call 877-249-8226 or visit http://marketplace.aami.org. Source code: PB.
Sterilizer repair and testing after a repair can involve more than just running a sterilization cycle and reviewing the cycle parameters before placing a sterilizer into service. The biomedical equipment technician needs to inform the sterile processing supervisor or sterilizer operator of the repairs and let them know if it was a minor or major repair; the sterilizer operator can then run and document the appropriate qualification testing before placing the sterilizer into service. To ensure compliance with Joint Commission standards and AAMI recommended practices, all results from the qualification testing must be documented as acceptable before placing the sterilizer back into use. Upon the successful completion of qualification testing the sterilizer will be ready to be placed into service.
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2009
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