Which sterilization method is best for heating-sensitive devices and uses a controlled gas environment?

• A. Steam autoclaving
• B. Ethylene oxide
• C. Dry heat
• D. Filtration

Answer: (B)

Heating-sensitive devices require a sterilization method that can operate at low temperatures and in a controlled gas environment. Ethylene oxide fits this need because it sterilizes effectively at room or mild temperatures as a gas, allowing penetration through complex device geometries and packaging without subjecting materials to heat or moisture. The process occurs in a carefully controlled environment where gas concentration, humidity, temperature, and exposure time are all tightly regulated, ensuring thorough microbial kill while preserving device integrity. After treatment, an aeration step is needed to remove residual ethylene oxide due to its toxicity, which is another aspect managed by the controlled system. In contrast, steam autoclaving uses high heat and moisture, which can damage heating-sensitive items; dry heat requires even higher temperatures; and filtration does not sterilize solid devices.