Medical Device Reprocessing Association of Ontario (MDRAO) Practice Exam

Which of the following are critical process variables for Ethylene oxide sterilization?

1. Time, pressure, humidity

2. Temperature, time, gas concentration

3. Temperature, humidity, pressure

4. Time, concentration, cooling

The correct answer is: Temperature, time, gas concentration

The correct answer highlights the critical process variables for ethylene oxide sterilization, which are indeed temperature, time, and gas concentration. Ethylene oxide is a commonly used gas for sterilizing medical devices that cannot withstand the high temperatures associated with steam sterilization. In this process, each of the identified variables plays a crucial role in achieving effective sterilization: - **Temperature**: The effectiveness of ethylene oxide sterilization increases with temperature. Higher temperatures facilitate the penetration of ethylene oxide into materials and enhance the sterilization process. However, there are limits to the temperature based on the material being sterilized, so careful control is required. - **Time**: The exposure time is critical for ensuring that the ethylene oxide has sufficient duration to interact with the microbial cells and achieve sterilization. Insufficient time can lead to survival of pathogens, rendering the sterilization ineffective. - **Gas Concentration**: The concentration of ethylene oxide is vital for the sterilization process. It must be maintained within an appropriate range to ensure that there is enough gas present to effectively sterilize the items being processed. In summary, the combination of these three factors is essential for ensuring a successful sterilization outcome when using ethylene oxide. Understanding and monitoring these variables