Which type of sterilization method uses ethylene oxide?

• A. Steam sterilization method
• B. Gas sterilization method
• C. Dry heat sterilization method
• D. Cold sterilization method

Answer: (B)

Ethylene oxide is primarily used in the gas sterilization method due to its effectiveness in penetrating a variety of materials and its ability to sterilize items that are heat-sensitive or moisture-sensitive. This method works well for medical instruments, plastic devices, and other complex equipment that cannot withstand high temperatures or steam.

Gas sterilization involves the use of ethylene oxide gas, which destroys the DNA of microorganisms, effectively killing bacteria, viruses, and fungal spores. The process typically requires specific environmental conditions, such as controlled temperature and humidity, to optimize the effectiveness of the ethylene oxide. Items processed with this method need to undergo aeration post-sterilization to remove residual gas, ensuring safety before their use.

In contrast, other methods mentioned in the question, such as steam and dry heat sterilization, utilize different mechanisms and substrates for sterilization, and cold sterilization usually employs chemical agents rather than a gaseous sterilant like ethylene oxide. Each method has its specific applications and limitations based on the type of instruments being sterilized and their material composition.