What Are The Scope Of Application, Advantages, Use Methods And Sterilization Steps Of Ethylene Oxide Sterilization

Scope of application

ethylene oxide has strong penetration and does not damage sterilized items, so most items that are not suitable for general methods of sterilization can be disinfected and sterilized with ethylene oxide, such as electronic instruments, optical instruments, medical devices, leather, cotton, chemical fiber, plastic products, endoscopes, and disposable diagnostic and therapeutic supplies. ethylene oxide is currently the main low-temperature sterilization method.

Advantages

1. It can kill all microorganisms, including spores, tuberculosis bacilli, bacteria, viruses, etc.
2. Sterilized items can be wrapped and sealed as a whole to maintain a sterile state before use.
3. Relatively speaking, ethylene oxide does not corrode plastics, metals, and rubber, and does not cause items to become yellow or brittle.
4. It can penetrate irregularly shaped, complex structured, and non-permeable items (such as long and thin catheters) for sterilization.
5. It can be used for sterilizing items that cannot be soaked in disinfectants, as well as for items that cannot be sterilized using dry heat, pressure, steam, and other chemical gases.

Instructions for use Because ethylene oxide is flammable, explosive, and toxic to humans, it must be carried out in a closed ethylene oxide sterilizer. (1) Types of ethylene oxide sterilizers and their applications: there are many types of ethylene oxide sterilizers currently used in the medical field, with large containers of 50- 100 cubic meter, medium-sized containers of 6-50 cubic meters, and small containers of 1-5 cubic meters. They each have different uses.

Large ethylene oxide sterilizer: generally used for large-scale sterilization of items, with a dosage of 0.8kg/m3~1.2kg/m3, operating at 55°C to 60°C for 6 hours. Medium ethylene oxide sterilizer: generally used for single-use medical items. This type of sterilization equipment has good automation and high degree of automation. It can use pure ethylene oxide or a mixture of ethylene oxide and carbon dioxide. Generally, the required conditions are: concentration, 80L-100m0; temperature, 50°C-60°C; relative humidity, 60%-80%; the sterilization process takes 6 hours and requires vacuum pumping to complete sterilization. The items to be sterilized are commonly sealed in plastic film packaging that can allow ethylene oxide to pass through. If there is a filter membrane on the small package that can filter air, the sterilization effect will be better. Small ethylene oxide sterilizer: mainly used in medical and health departments for a small number of medical supplies. Currently, it uses either 100% pure ethylene oxide or a mixture of ethylene oxide and carbon dioxide. This type of sterilizer has a high degree of automation, can automatically evacuate air, add drugs, automatically control temperature and humidity, and automatically adjust sterilization time. The requirements for medium and small ethylene oxide sterilizers are as follows: good pressure resistance and sealing performance, should be able to withstand a water pressure test of 1.25 times the working pressure, no leakage, can be vacuum pumped to a vacuum level of 533 kPa or higher, accurate drug addition, good return performance, can adjust the disinfection concentration, temperature, and relative humidity. After disinfection, when exposed to ambient air, the input air should pass through a high-efficiency filter, which can remove more than 99.6% of 0.3um particles, and the residual gas should be harmless. The residual gas in the sterilized items should be less than 152mg/m3, and the residual concentration of ethylene oxide should be less than 2mg/m3.

(2) Preparing and packaging items before sterilization Items to be sterilized must be thoroughly cleaned, and care should be taken not to clean with saline water. There should be no water or moisture on the items to be sterilized to avoid affecting the penetration and sterilization effect of ethylene oxide. ethylene oxide can be used for the sterilization of almost all medical items, but it is not suitable for food, liquids, oils, powders, and other materials. Suitable packaging materials for ethylene oxide sterilization include paper, composite film, non-woven fabric, breathable packaging, and polyethylene oxide. Materials not suitable for ethylene oxide sterilization include PVC, cellophane, nylon, acetate, polyvinylidene chloride, and non-permeable polypropylene. Changes in packaging materials should be validated to ensure the reliability of the sterilization of the sterilized items.

(3) Loading of sterilized items Sterilized items should have space on all sides within the sterilization cabinet (items should not be in direct contact with the cabinet). Items should be placed in metal mesh baskets or on metal mesh racks; the loading capacity should not exceed 80% of the total volume inside the cabinet.

(4) Processing The operation and usage instructions provided by the ethylene oxide oxide sterilizer manufacturer must be strictly followed. Suitable sterilization parameters should be chosen based on the type of items to be sterilized, their packaging, loading capacity, and method.

Relationship between concentration, temperature, and sterilization time: Within a certain range, increasing the temperature and concentration can shorten the sterilization time. When using ethylene oxide oxide for sterilization, it's crucial to select temperature, concentration, and time parameters reasonably.

@Controlling relative humidity of the sterilization environment and the moisture content of items: The inherent moisture content of items and their water content both significantly affect the effectiveness of ethylene oxide oxide sterilization. Generally, a relative humidity of 60%-80% is preferable. The moisture content affects the penetration of ethylene oxide oxide and its alkylating effect, thereby reducing its germicidal ability. Excessive moisture can hinder the sterilization process. To achieve the required humidity level, firstly, the relative humidity of the sterilization environment should be controlled at 50%. Secondly, controlling the humidity level close to this figure is important.

@Attention to the influence of extracellular substances on sterilization effectiveness The more organic substances present on the surface of an item, the more likely it is to hinder sterilization. Organic materials can impede the penetration of ethylene oxide oxide and partially react with it. Therefore, before ethylene oxide oxide sterilization, items must be thoroughly cleaned of any organic and inorganic contaminants to ensure successful sterilization.

Sterilization process: The ethylene oxide oxide sterilization process should include preheating, pre-wetting and vacuuming, introducing gaseous ethylene oxide oxide to the predetermined concentration, maintaining the sterilization time, purging residual ethylene oxide oxide from the sterilization chamber, and releasing to remove any remaining ethylene oxide oxide from the sterilized items.

ethylene oxide oxide sterilization can use 100% pure ethylene oxide oxide or a mixture of ethylene oxide oxide and carbon dioxide. It is prohibited to use fluorinated hydrocarbons. Ventilation after ethylene oxide oxide sterilization can be conducted in the sterilization cabinet or in a dedicated ventilated area, but natural ventilation should be avoided. Air recirculated should pass through high-efficiency filters to remove 99.6% of particles larger than 0.3 micrometers. The residue of ethylene oxide oxide mainly refers to the residual ethylene oxide oxide and its by-products in the items and packaging materials after ethylene oxide oxide sterilization. The amount of residual ethylene oxide oxide depends on the materials of the sterilized items, the sterilization parameters, the packaging materials, the size of the packaging, the loading capacity, and other related parameters. For example, polyvinyl chloride tubing requires ventilation at 60°C for 8 hours or 50°C for 12 hours; some materials may require shorter ventilation times, such as metal and glass, which can be used immediately, while others may require longer ventilation times, such as internal cardiac pacemakers.

ethylene oxide oxide emissions: Ventilation of ethylene oxide oxide must meet environmental regulations and requirements. Ventilation should be directed from the sterilization equipment to the outside environment, and the exhaust should point downward at the exit to prevent the accumulation of gases within the facility. Installation of the entire exhaust system, including pipes and drainage troughs, must be sealed to prevent the overflow of ethylene oxide oxide into the surroundings and contamination of the work environment. Professional engineering installation experts should be consulted, adhering to the requirements of the ethylene oxide oxide sterilizer manufacturer. If ethylene oxide oxide is discharged into water, the entire exhaust system must be sealed; otherwise, large amounts of heated ethylene oxide oxide can overflow into the water, polluting the surrounding work environment.