- Certified Medical Device Reprocessing Technician Low-Temperature Sterilization Questions and Answers Flashcards

What is ethylene oxide (ETO) sterilization and when is it used in medical device reprocessing?

Answer: A chemical sterilization method using ETO gas for heat-sensitive and moisture-sensitive devices that cannot withstand steam sterilization

ETO sterilization uses ethylene oxide gas to sterilize medical devices that would be damaged by the high temperatures and moisture of steam sterilization, such as flexible endoscopes, certain plastics, electronics, and battery-powered devices.

What is hydrogen peroxide gas plasma sterilization?

Answer: A low-temperature sterilization method that uses hydrogen peroxide vapour converted to a plasma state by radiofrequency energy to sterilize medical devices

Hydrogen peroxide gas plasma (such as STERRAD systems) uses a combination of hydrogen peroxide vapour and low-temperature plasma (ionized gas) to achieve sterilization at temperatures around 45-55°C, suitable for many heat-sensitive devices.

What are the primary safety hazards associated with ethylene oxide sterilization?

Answer: ETO is a toxic, carcinogenic, mutagenic, and flammable gas requiring strict exposure controls and monitoring

ETO is classified as a known human carcinogen and is mutagenic, making it a significant occupational health hazard. Canadian OELs are very low, and strict engineering controls, monitoring, and safety protocols are required.

Why is aeration important after ethylene oxide sterilization?

Answer: To remove residual ethylene oxide gas absorbed by device materials, which is toxic to patients and staff

ETO gas is absorbed by many materials during sterilization. Without adequate aeration, residual ETO on devices can cause burns, irritation, hemolysis, and other toxic reactions in patients, and poses an inhalation hazard to staff.

Which types of materials are NOT compatible with hydrogen peroxide gas plasma sterilization?

Answer: Cellulose-based materials (paper, cotton, linen), liquids, and devices with long narrow lumens below specified dimensions

Cellulose-based materials absorb hydrogen peroxide and prevent plasma formation. Liquids are not compatible because the process requires a deep vacuum. Long narrow lumens may not allow adequate peroxide penetration to achieve sterilization.

What biological indicator is used to monitor ethylene oxide sterilization cycles?

Answer: Bacillus atrophaeus (formerly B. subtilis var. niger)

Bacillus atrophaeus spores are used as the biological indicator for ETO sterilization because they are highly resistant to ETO gas. If the sterilization process kills these resistant spores, it confirms that less resistant organisms were also eliminated.