Flash Steam Sterilization, Quality Assurance and the Operating Room: A Practical Guide
by Arthur Henderson, RN; Gaylyne Marshall, RN; clinical education specialists; Susan Fagan, RN, senior clinical education specialist, STERIS Corporation

Quality control of sterilization processes is critical for reducing the chance of nosocomial infections and improving patient safety. This is especially true when items are flash-sterilized in the operating room (OR) and immediately utilized for a patient. The immediacy of use places an extra focus on the quality control practices employed by the OR to ensure that devices that are flash sterilized are safe at the time of use. Due to the conflicting recommendations of biological and chemical indicator manufacturers, the quality control protocols for flash sterilization processes vary greatly throughout the medical industry. This can leave any OR manager wondering, "What must I do to ensure that the flash sterilization processes used in my OR meet best practices standards?" The surest way to maintain best practices is to be thorough in your quality assurance process.

Quality control of the flash sterilization process should include three critical functions:
1. Equipment qualification
2. Product testing
3. Routine monitoring

Equipment Qualification
Sterilization quality control in the OR starts with the equipment. Without properly functioning equipment, sterilization is impossible. Equipment qualification must be performed when the sterilizer is first installed and after any major repairs. Two tests are used in this qualification: biological testing for all cycles and air removal qualification testing for prevacuum cycles only. In addition to these tests, the electrical supply water supply and other mechanical requirements for the unit must be verified whenever systems are installed or moved.

Biological Qualification
The biological qualification involves performing three consecutive biological challenges for each cycle type and flash sterilization configuration. First, generate a list of all the flash sterilization cycles that are or will be used on the sterilizer. This list would include gravity flash at 270‰F, prevacuum flash at 270‰F, and any other cycles you use. Next, list all the types of configurations sterilized with these cycles; open mesh trays, protective organizing cases (rigid containers), rigid sterilization containers appropriate for flash, etc. The goal of this exercise is to identify all the possible combinations of cycles and configurations that would be used when flash sterilizing items.

The last step is to perform three consecutive biological test cycles with each test condition. Always choose the shortest exposure time if more than one exposure time is used for a given cycle and configuration.

If you are flash-sterilizing an open mesh tray for both 3 minutes and 10 minutes, only the 3 minute exposure time is tested. A minimum of one biological indicator is placed within each configuration. It is very important that no items are placed in the trays, cases, or containers. The instrumentation would slow the come-up time of the steam sterilizer an allow more kill during the come-up time. A successful qualification occurs when all the biological indicators demonstrate no growth. For more information on the specifics of the testing process, refer to ANSI/AAMI ST37.

Several choices of biological indicators exist today for this application. The most common are self-contained biological indicators (SCBIs). SCBI contain bacterial spores impregnated into a piece of filter paper and housed within a vial containing sterile growth medium. The bacterial spores are cultured and incubated after the sterilization cycle by breaking the ampoule of growth medium within the vial and incubating the vial as directed by the manufacturer, typically 24 to 48 hours. A second type of SCBI uses an enzyme-based early-readout component of one or three hours, with traditional spore growth assay of 24-48 hours. It must be noted that for this critical test, the Association for the Advancement of Medical Instrumentation (AAMI) recommends conventional BI outgrowth. In the section entitled "Biological indicators with enzyme-based early-readout capability," AAMI states that "early read-out capabilities should not be relied upon for these critical assessments," which includes equipment qualification upon installation and after major repairs.

Air Removal Qualification
The air removal qualification is only required for those steam sterilizers with a prevacuum sterilization cycle. The qualification consists of three consecutive air removal tests (Bowie-Dick tests) to demonstrate that sufficient air can be removed by the sterilizer from the representative porous item. Many sterilizer manufacturers have preprogrammed test cycles for this test. Detailed instructions for the construction and testing of Bowie Dick Test Packs can be found in the AAMI standard ANSI/AAMI ST46. A successful qualification occurs when all the Air Removal Test Cycles demonstrate complete air removal.

Equipment qualification is the first required element of a good quality control program. Failure of any part of this qualification indicates that the sterilizer is malfunctioning and requires servicing or repair. When servicing is complete, all qualification testing must be successfully completed before the sterilizer can be put back into service.

Product Testing
Product testing is the next step in a good quality control process.

This testing uses biological indicators to confirm that the cycles and configurations used within the facility for flash sterilization effectively kill microorganisms on the items. Product testing should be performed periodically (once a year) and any time there is a significant change to the process. Some examples of significant changes include:
• Change in the exposure time or temperature
• Change in the cycle type (gravity to prevacuum)
• Change in the packaging configuration
(wrapped trays to a rigid sterilization container)
• Receipt of a new type of instrument

To perform product testing, start with the same list of cycle types and configurations identified during the qualification of the sterilizer, but this time add to the list the type of instruments and quantity being flash-sterilized in a single cycle. Next, test the easiest and hardest combinations to sterilize for each cycle type and configuration. Typically the easiest is the load with the smallest and fewest items. The hardest load would most often be the largest one with the most instruments, though exceptions do exist. If you are doing product testing for the first time, you should consult with your sterile processing manager for help with the testing.

Routine Monitoring
After the equipment has been qualified and the procedures and processes of sterilization have been verified, routine monitoring is performed according to AAMI standards to capture any shifts in the performance of the equipment or personnel that would change the effectiveness of the sterilization process. Routine monitoring helps to ensure that the equipment is still working and the operators have not made a mistake.

Biological Monitoring of the Sterilizer
Equipment performance is verified weekly using biological indicators. A single biological indicator test is performed for each of the cycle types and configurations that are used. To perform the test, a biological indicator is placed within an otherwise empty configuration such as an open mesh tray, protective organizing case (rigid container), or rigid sterilization container appropriate for flash. The item is processed in an otherwise empty sterilizer chamber, using the cycle type identified for the configuration being tested and the shortest exposure time. Several choices of biological indicators are used for this application. The most common are the traditional SCBIs and those with the additional enzyme-based component. AAMI recommends that an enzyme-based early-readout biological indicator complete its full incubation time to test for spore growth on a weekly basis.

Air Removal Monitoring of the Sterilizer
Air removal testing (Bowie-Dick) is required to be performed each day that a prevacuum cycle is run. The test must be performed before the prevacuum flash cycle is run.

Monitoring Flash Cycles
Each sterilization cycle must be monitored. This is accomplished by reviewing cycle printouts and chemical indicator strip results. Every tray, container, or other configuration must contain a chemical indicator during sterilization. The chemical indicator is placed in the most difficult-to-penetrate location within the configuration. Several types of chemical indicators are available for monitoring the flash sterilization cycle. AAMI has defined each type of chemical indicator and its performance.

CLASS 1: The most basic indicator is the process indicator, which includes such things as tapes, data cards and indicator strips. Process indicator strips simply verify that the cycle completed, but are not necessarily linked to the achievement of critical sterilization parameters like time, temperature and steam quality. Process indicators give you minimal assurance that steam was present but not that the parameters of sterilization were met.

CLASS 4: Class 4 indicators provide more sterility assurance than Class 1 indicators by monitoring the achievement of 2 or more critical parameters for sterilization (time, temperature, or steam quality). Class 4 indicators are also held to a higher standard of accuracy and allow a narrower tolerance than process indicators. This means the indicator change occurs much further into the sterilization cycle.

CLASS 5: The highest level of assurance is
provided by the Class 5 integrating indicators. Class 5 indicators monitor all the critical parameters of steam sterilization (time, temperature and steam quality) and have been correlated to the death curve of a biological indicator. This means that the Class 5 integrating indicator will demonstrate a "pass" when sterilization conditions were met that would kill a biological indicator, but will demonstrate a "fail" if the conditions would not have killed a biological indicator. Class 5 indicators are also held to a higher standard of accuracy and maintain even narrower tolerances than Class 4 indicators. As a predictor of biological response, Class 5 integrators provide a high assurance level.

What about Implants?
The Association of peri-Operative Registered Nurses (AORN), The Centers for Disease Control and Prevention (CDC) and the Association for the Advancement of Medical Instrumentation (AAMI) all agree that implants should not be flash-sterilized. The implant is placed in an avascular environment that would promote infections from improperly sterilized or contaminated implants. Since flash sterilization can increase the risk of contamination of the implant during transport from the sterilizer to the patient, flash sterilization of implants should be avoided. The need to flash-sterilize implants can be eliminated through careful planning and inventory management.

Should a situation exist in which an implant must be flash-sterilized, both AAMI and AORN recommend monitoring the cycle with a biological indicator. The implant must then be quarantined until the result of the biological testing is known. Of the biological indicators available on the market, the SCBIs with enzyme-based early-readout capabilities give the fastest results in one or three hours, depending on the product used. However, even one hour is a long time to expose an unpackaged flash-sterilized implant to environmental contaminants.This creates a dilemma for the facility: should they quarantine the implant until the biological results are known and increase the potential for contamination of the unwrapped implant, or should they use the implant without waiting for the biological result?

One solution proposed through AAMI is a procedure for releasing the sterilized implants prior to knowledge of the biological indicator results. In this proposed method, the implant is released using other means to ensure that the sterilizer’s performance was adequate. Cycle printouts and other indicators such as the Class 5 indicators are used. This method requires documentation of the early release and subsequent follow-up with the biological indicator’s final results, but it can be used to reduce the risk of environmental contamination of a flash-sterilized implant before it is implanted in the patient.
Ultimately, the decision to flash-sterilize an implant is the facility’s responsibility. The decision should be based on several considerations, including the hospital’s surgical site infection rates, the location and configuration of the surgical suites in relationship to the sterilizer, and the assessment of a patient's risk for a surgical site infection. The decision to flash-sterilize an implant should never be based upon the need to decrease instrument turnaround time, an inventory shortage of surgical instruments, or the desire to save time.

Conclusion
The success of any quality control protocol for flash sterilization rests on the practices employed by the facility's central service and surgical professionals. Policies and procedures are needed to provide instruction and guidance and to document the total quality control process from the cleaning and preparation of the instrument through the use of that instrument on a patient. It is also imperative to reinforce those procedures by providing ongoing training to anyone who is operating the sterilizers. Given a choice, terminal sterilization is the preferred method of reprocessing instruments However, flash sterilization can be performed successfully and responsibly in the surgical suite by establishing and following a thorough quality control program.

• ANSI/AAMI ST37 "Flash Sterilization: Steam sterilization of patient care items for immediate use", 1996
• ANSI/AAMI ST46 "Steam sterilization and sterility assurance in health care facilities", 2002
• ANSI/AAMI ST46 "Steam sterilization and sterility assurance in health care facilities", 2002
• ANSI/AAMI ST60 "Sterilization of healthcare
products—chemical indicators—Part 1: General Requirements"1996
• AORN "Standards, Recommended Practices, and Guidelines", 2004
• The Centers for Disease Control and Prevention (CDC) "Guidelines for Prevention of Surgical Site Infection", 1999