High Temperature sterilization

High Temperature sterilization

High Temperature sterilization

Based on spaudling classification the critical items and semi critical items need to be sterilized before being used for the safety of the patients that will touch the patient sterile body cavity so all microorganisms need to be destroyed to prevent diseases associated with the items used , to achieve this target we have to use sterilizers that can be high temperature sterilizer or low temperature sterilizers the widely used High temp sterilizers are steam sterilizer and the flash sterilizers (as long as most instrument are heat stable)

 

The steam sterilizers: the most general sterilizers present in almost all health care facilities worldwide as it is nontoxic, inexpensive (compared to low –temperature sterilizers), short duration cycle the sterilization is achieved by exposing the required item for sterilization to steam at particular temperature and pressure for the particular time so four parameters (Steam, Temperature, Pressure and Time) are monitored for each cycle. The ideal steam for sterilization is dry saturated steam and entrained water (dryness fraction >97%). Pressure serves as a means to obtain the high temperatures necessary to quickly kill microorganisms.

The two common steam-sterilizing temperatures are 121 C and 132 C. These temperatures (and other high temperatures) must be maintained for a minimal time to kill microorganisms. Identified least exposure durations for sterilization of wrapped healthcare supplies were 30 minutes at 121 C (250 F) in a gravity displacement sterilizer or 4 minutes at 132C in a pre-vacuum sterilizer. At steady warmth, sterilization times differ depending on the object, whether the item is wrapped or unwrapped, and the steam sterilizer type (gravity displacement autoclave or the high-speed pre vacuum sterilizer).

 

Moist heat destroys microorganisms by the irreversible coagulation and denaturation of enzymes and structural proteins, Remember: proper decontamination of the instrument as per the rule no dirty object can be sterile

 

To make sure that the Autoclave is working in a proper way you have to test the autoclave by a challenge tests the first one is Bowie-Dick test that is used to detect air leaks and inadequate air removal that should be placed in the center of the pack horizontally in the chamber and use the cycle of Bowie-dick at 134C for 3.5 min. the test has to be performed before the first cycle after installation of the sterilizer , after period preventive maintenance and after any maintenance plus the daily use. Chemical indicator is another test used to be placed inside the sterilization bag or attached to the sterilization pack or pouch to indicate this item is already prepared inside the autoclave to be clear for the end user

 

The steam cycle is monitored by mechanical, chemical, and biological monitors. Heat sterilizers usually are monitored using a printout (or graphically) by measuring the temperature, the time at a temperature, and pressure. The effectiveness of steam sterilization is monitored with a biological indicator containing spores of Geobacillus stearothermophilus (formerly Bacillus stearothermophilus). Positive test results are a nearly rare event and can be attributed to mechanic failure, low steam distribution, or machine malfunction that lead immediate intervention by recall the products

 

 

Flash sterilizer:  Sterilization of an unwrapped article at 132 C for 3 minutes at 27-28 lbs. of pressure in a pressure displacement sterilizer. Currently, the time needed for flash sterilization depends on the sterilizer and the item (i.e., porous vs non-porous items). Correctly performed flash sterilization is an effective process for the sterilization of critical medical devices in the proper procedure is used. Flash sterilization is a modification of conventional steam sterilization (either gravity, pre-vacuum, or steam-flush pressure-pulse) in which the flashed item is placed in an open tray or is placed in a uniquely designed, closed, rigid box to provide for speedy diffusion of steam. Historically, it is not recommended as a routine sterilization process because of the lack of timely biological indicators to observe production, lack of protective packaging following sterilization, probability for pollution of prepared items during transportation to the operating rooms, and the sterilization cycle parameters (i.e., time, temperature, pressure) are minimal.

It is considered acceptable for processing cleaned patient-care items that cannot be grouping, sterilized, and saved ere use. It also is used when there is inadequate chance to sterilize an item by the chosen package method.

Remember: Never Ever use Flash sterilizer for implantable items

 

Reference  

 

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