Final answer:
The autoclave cycle used to release steam under pressure is the prevacuum cycle. It involves removing air with a high-speed vacuum before introducing steam to ensure effective sterilization of packaged instruments.
Step-by-step explanation:
The autoclave cycle that allows the steam under pressure to be released from within the chamber is the prevacuum cycle. This cycle is crucial for many sterilization applications. In prevacuum sterilizers, air is removed from the chamber using a high-speed vacuum before steam is introduced. This ensures that air is completely eliminated, allowing the steam to penetrate more effectively. This type of sterilization is essential for the sterilization of packaged instruments, as it makes sure that every part of the load is properly sterilized.
Conversely, gravity displacement sterilizers release steam into the chamber to push out the heavier air, but this method may require longer cycles for larger loads or instances where complete air displacement is difficult. Autoclaves utilize moist-heat sterilization to achieve temperatures above the boiling point of water, typically 121 °C or 132 °C under pressure, to sterilize items from harmful microorganisms including endospores, which are known for their resistance to boiling temperatures. The thorough removal of air is essential for effective sterilization as it ensures direct contact of steam with the materials being sterilized.