Ethylene Oxide (EO) Medical Device Sterilization: What You Need To Know

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If you plan to begin producing medical devices that require sterilization before they are packaged, such as surgical masks, then you may be looking into your sterilization options.

While there are many other medical device sterilization methods, such as heat sterilization, about 50 percent of all medical devices in the United States today are sterilized with ethylene oxide (EO) due to the unique benefits of the EO device sterilization process. 

Read on more about EO device sterilization, including how it works and its unique benefits. 

EO Sterilization Requires No Intense Heat or Moisture 

Ethylene oxide sterilization is a great option when sterilizing medical devices that are sensitive to heat, like surgical masks, polymers, and glass, because it is considered a cold sterilization process. In addition, EO sterilization requires no steam, which also makes it a good option for items that cannot get wet while being sterilized. In fact, EO sterilization can occur at temperatures as low as 90°F and humidity levels as low as 30 percent. 

However, if your medical devices can tolerate higher temperatures and higher humidity levels, then increasing the heat and humidity settings on an EO sterilization machine slightly can speed up the sterilization process. 

EO Sterilization Takes Place in Five Stages

A complete ethylene oxide sterilization cycle takes place in five stages. These stages include sterilization chamber humidification, the introduction of EO gas, gas exposure time, evacuation or removal of EO gas, and air washes of the medical devices to remove EO residue. While this may sound like a lengthy sterilization process, all five stages are typically completed in about 2.5 hours and can often be performed in the same disinfection chamber.

Not only does the performance of all sterilization steps in the same chamber speed up the EO sterilization process, but it also helps limit human EO gas exposure.

Mechanical Aeration Removes EO Residue Quickly

While ethylene oxide is a known human carcinogen, an additional step called aeration is performed after the five sterilization stages and helps remove all EO residue from medical devices before they are packaged or used.

While aeration can be performed by simply allowing the EO to naturally dissipate from the materials for about 7 days at 20°C, mechanical aeration is a much quicker EO residue removal process. During mechanical aeration, medical instruments are left in a heated chamber at 50 to 60°C for just 8 to 12 hours. 

When choosing how to sterilize your medical devices before packaging them, keep these EO sterilization facts in mind. Enlist the help of an EO sterilization service if you would like to skip the purchase of your own machine and leave this sterilization process in the hands of trained experts.