Instructions
Since ethylene oxide is flammable, explosive, and toxic to humans, it must be carried out in a closed ethylene oxide sterilizer.
(1) Ethylene oxide sterilizer and its application:
1) There are many types of ethylene oxide sterilizers currently in use. Large containers have tens of cubic meters, medium ones have 1-10 cubic meters, and small ones have a few tenths to 1 cubic meter. They each have different purposes.
Large-scale ethylene oxide sterilizer: generally used for the sterilization of a large number of processed items, with a dosage of 0.8kg/m³～1.2kg/m³, and an action of 6h at 55℃～60℃.
3) Medium-sized ethylene oxide sterilizer: generally used for sterilization of disposable medical supplies. This kind of sterilization equipment is complete and highly automated, and can be used with pure ethylene oxide or a mixed gas of ethylene oxide and carbon dioxide. Generally required sterilization conditions are: concentration, 800 mg/L～1000mg/L, temperature, 55℃～60℃, relative humidity 60%～80%, action time 6 hours. Vacuum is required to complete the sterilization. Sterilized items are usually sealed and packaged with plastic film permeable to ethylene oxide. If there is a filter membrane that can filter air on the small package, the sterilization effect will be better.
4) Small ethylene oxide sterilizers are mostly used in the medical and health departments to process a small amount of medical equipment and supplies. Currently, there are 100% pure ethylene oxide or a mixture of ethylene oxide and carbon dioxide. This kind of sterilizer has a relatively high degree of automation, can automatically vacuum, automatically add medicine, automatically adjust the temperature and relative humidity, and automatically control the sterilization time.
5) The requirements for medium and small ethylene oxide sterilizers are: good pressure resistance and airtight performance, should be able to withstand a hydraulic test of 1.25 times the working pressure, without degeneration and leakage, and can be vacuumed To above 53.3 kPa; accurate dosage, good heat preservation performance, can adjust the temperature and relative humidity in the sterilizer; when flushing with external ambient air after sterilization, the input air passes through a high-efficiency filter, which can filter out particles ≥0.3µm 99.6% or more; the discharged residual ethylene oxide is harmlessly treated, the residual ethylene oxide in the sterilized articles should be less than 15.2mg/m; the concentration of ethylene oxide in the sterilization environment should be less than 2mg/ m.
(2) Preparation and packaging of items before sterilization: Items that need to be sterilized must be thoroughly cleaned. Note that they cannot be cleaned with saline. There should be no water droplets or too much water on the sterilized items to avoid dilution and hydrolysis of ethylene oxide. . Ethylene oxide can be used for the sterilization of almost all medical supplies, but it is not suitable for the sterilization of food, liquids, oils, talcum powder and animal feed. Packaging materials suitable for ethylene oxide sterilization include paper, composite dialysis paper, cloth, non-woven fabrics, ventilated rigid containers, polyethylene, etc.; packaging materials that cannot be used for ethylene oxide sterilization include metal foil, Polyvinyl chloride, cellophane, nylon, polyester, polyvinylidene chloride, impermeable polypropylene. Changes to packaging materials should be verified to ensure the reliability of the sterilization of the sterilized items.
(3) Sterilized items loading: The items loaded in the sterilizer should have gaps up, down, left, and right (the sterilized items cannot touch the cabinet wall), and the items should be placed in a metal mesh basket or on a metal net rack; the amount of items loaded is not Should exceed 80% of the total volume in the cabinet.
(4) Sterilization: It should be implemented in accordance with the operating instructions of the manufacturer of the ethylene oxide sterilizer; select the appropriate sterilization parameters according to the type, packaging, loading and method of the sterilized items.
1) The relationship between concentration, temperature and sterilization time: Within a certain range, the increase in temperature and concentration can shorten the sterilization time. When using ethylene oxide for sterilization, the temperature, concentration and time parameters must be selected reasonably.
2) Control the relative humidity of the sterilization environment and the water content of the items: The water content of the bacteria itself and the water content of the sterilized items have a significant impact on the sterilization effect of ethylene oxide. Under normal circumstances, the relative humidity is 60% to 80%. Too little water content will affect the penetration of ethylene oxide and the alkylation of ethylene oxide, reducing its sterilization ability; too much water content will dilute and hydrolyze ethylene oxide, which will also affect the sterilization effect. In order to achieve the ideal humidity level, the first step is to pre-wet the sterilized material. Generally, the sterilized material must be placed under 50% relative humidity for at least 2 hours; in the second step, a humidification device can be used to ensure the ideal humidity in the cabinet. Level.
3) Pay attention to the influence of the bacteria in vitro protection on the sterilization effect: The more organic matter on the surface of the bacteria, the more difficult it is to kill; the organic matter can not only affect the penetration of ethylene oxide, but also consume part of the ethylene oxide. Microorganisms in inorganic salts or organic crystals are difficult to kill with ethylene oxide. Therefore, before ethylene oxide sterilization, organic and inorganic contaminants on the items must be fully cleaned to ensure successful sterilization.
Sterilization program
①Ethylene oxide sterilization procedures need to include preheating, pre-wetting, vacuuming, introducing vaporized ethylene oxide to reach a predetermined concentration, maintaining the sterilization time, clearing the ethylene oxide gas in the sterilizer, and analyzing to remove Residues of ethylene oxide in sterilized items.
②100% pure ethylene oxide or mixed gas of ethylene oxide and carbon dioxide can be used for ethylene oxide sterilization. The use of Freon is prohibited.
③Analysis can be continued in an ethylene oxide sterilizer, or it can be placed in a special fume hood, and natural ventilation should not be used. The repeatedly input air should be filtered with high efficiency, which can filter out more than 99.6% of particles ≥0.3um.
④Ethylene oxide residue mainly refers to the ethylene oxide remaining in articles and packaging materials after ethylene oxide sterilization and its two by-products, chloroethanol ethane and ethylene glycol ethane; exposure to excessive ethylene oxide Alkane residues can cause burns and irritation to patients. The amount of ethylene oxide residue is related to the materials of the sterilized articles, the parameters of the sterilization, the packaging materials and the size of the packaging, the loading capacity, and the analysis parameters. When the polyvinyl chloride catheter is at 60℃, it is analyzed for 8h; when it is 50℃, it is analyzed for 12h. Some materials can shorten the resolution time, such as metal and glass can be used immediately, and some materials need to extend the resolution time, such as a built-in pacemaker. 5) Ethylene oxide emission: The first choice for ethylene oxide emission in hospitals, the installation requirements: There must be a special exhaust piping system, and the exhaust pipe material must be ethylene oxide and not permeable such as copper pipes. There should be no flammable materials and building air inlets such as doors or windows within 7.6m from the exhaust; if the length of the vertical part of the exhaust pipe exceeds 3m, a water collector must be installed, and the exhaust pipe should not be dented Or the loop will cause water vapor to accumulate or freeze in winter, blocking the pipe; the exhaust pipe should be led to the outdoors and reversed at the exit to prevent water vapor from staying on the pipe wall or causing the pipe wall to be blocked; a professional must be requested Installation engineer, and combined with the requirements of the ethylene oxide sterilizer manufacturer to install. If ethylene oxide is discharged into the water, the entire discharge system (pipes, sinks, etc.) must be sealed, otherwise a large amount of hot ethylene oxide will overflow from the water and pollute the surrounding working environment.
