Medical Device Reprocessing Association of Ontario (MDRAO) Practice Exam

Which critical process is NOT involved in vaporized hydrogen peroxide sterilization?

1. Concentration

2. Time

3. Humidity

4. Pressure

The correct answer is: Pressure

Vaporized hydrogen peroxide (VHP) sterilization is a low-temperature process that utilizes vaporized hydrogen peroxide to achieve sterilization. This method is critical in the reprocessing of medical devices, particularly when heat and moisture-sensitive items are involved. Concentration is vital in VHP sterilization because the effectiveness of the sterilant is highly dependent on its concentration in the chamber during the sterilization cycle. Appropriate levels of hydrogen peroxide need to be achieved to ensure that any microbial load is effectively eradicated. Time also plays a crucial role in this process. The duration of exposure to vaporized hydrogen peroxide directly affects the sterility assurance level. If the exposure time is insufficient, sterilization cannot be assured. Humidity is another critical factor since hydrogen peroxide has increased efficacy in the presence of moisture. The presence of water vapor enhances the sporicidal activity of hydrogen peroxide, which is why humidity levels need to be controlled and monitored in the sterilization chamber. Pressure, however, is not a critical process in the context of VHP sterilization. Unlike other sterilization methods that rely on high pressure (like steam sterilization), VHP sterilization operates at atmospheric pressure and does not require changes in pressure to achieve its sterilization goals. Thus, among the