Medical Device Reprocessing Association of Ontario (MDRAO) Practice Exam

What is the minimum pressure required for gravity steam sterilization?

1. 10 psi

2. 15 psi

3. 20 psi

4. 25 psi

The correct answer is: 15 psi

Gravity steam sterilization requires a minimum pressure of 15 psi to ensure effective sterilization. This pressure is crucial because it correlates with the temperature achieved during the sterilization process. At 15 psi, steam reaches a temperature of approximately 121°C (250°F), which is considered optimal for the killing of microorganisms, including bacterial spores. Achieving this pressure allows for effective penetration of steam into the sterilization load, facilitating the transfer of heat necessary to sterilize the instruments adequately. Additionally, maintaining the correct pressure helps in achieving and sustaining the required temperature throughout the sterilization cycle, contributing to the overall efficacy of the process. Proper operating pressures are essential for compliance with sterilization standards and for ensuring patient and staff safety. Other pressures, either lower or higher, may not provide the necessary conditions for effective sterilization and could potentially result in incomplete sterilization, leading to increased risks of infection or contamination.