Pages

Sterility Assurance

All the efforts that go into the preparation of instruments are futile if the sterilization process itself is not successful. There is no way of seeing that instruments are sterile by simply observing the sterilizers and packs, even though a chemical or mechanical indicator may have changed. An indicator such as autoclave tape may change colour when exposed to heat, but there is a possibility that the heat was not present for the proper length of time or that there was inadequate pressure.

Indicators that go on the outside of the packs are useful for identifying processed and unprocessed packs. Failure of sterilization can occur due to mechanicalmalfunction of the sterilizer or due to operator error. There are several methods to provide assurance of sterility.

Prevention of overloading

Most sterilizers have a system to notify the operator of mechanical malfunction,but sterilizers cannot notify the operator whether the contents of the instrument packs or cassettes are sterile or not. Operator error in loading the sterilizer could result in failure to sterilize all the packs in spite of the proper time, temperature and/or pressure. It is important to avoid overloading the sterilizer or loading packs and cassettes on top of one another; use of a cassette system helps to reduce operator error due to overloading. The heat and/or steam must be able to circulate throughout the chamber and between the packs or cassettes for successful sterilization.

Chemical indicators
Chemical indicators indicate the presence of certain conditions during the sterilization cycle, such as the presence of heat and steam. There are five classifications of indicators recognized by the FDA, and it is important to note that it is now recommended that all packs or cassettes include internal and external indicators.

Class 1 — Process Indicators. These are placed on the outside of packs and are useful in determining which packs have been properly processed versus those that have not. Class 1 process indicators include autoclave tape and the colour change indicators embedded on the outside of sterilization packaging materials.

Class 2 — Bowie-Dick Indicators. These show the pass/fail in prevacuum sterilizers. This test is conducted daily with the chamber empty, during the first cycle of the sterilizer, and is available as a kit from commercial sterilization monitoring companies.

Class 3 — Temperature-Specific Indicators. These react to one of the critical parameters of sterilization and indicate exposure to a specific value such as temperature or psi.

Class 4 — Multi-parameter Indicators. These react to two or more of the critical parameters in the same manner as Class 3 indicators.

Class 5 — Integrating indicators. These are designed to react to all critical parameters of sterilization cycles. When used properly, integrating indicators may serve as the basis for the release of processed items, excluding implants. It is important to follow the manufacturer's specific instructions for use regarding a test challenge pack.
Autoclavable pouches with color change indicators
Autoclavable pouches with color change indicators
Biological monitoring

The use of biological monitors (spore tests) is the most reliable method to validate that the sterilizer is functioning and that the sterilization of instruments is effective.These monitors consist of paper strips or vials impregnated with bacterial spores that are specifically resistant to the sterilization process. New spore tests have been developed that enable completion of biological monitoring in-office and yield results in as little as 24 hours. These tests allow quick remediation and validate proper infection control procedures without a long lag time during which the sterilization procedure may have become ineffective but is not known. It is recommended that biological monitoring be conducted at least weekly and with every load that includes an implantable device.Once sterilization is achieved and its efficacy assured, it is important that the sterilized instruments are properly stored and distributed.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.