During the autoclave process, the chamber is loaded with medical instruments. The technician checks the load to make sure it is properly distributed for maximum steam penetration. Chemical and biological indicators may be added to validate the effectiveness of the cycle. The door is then closed and sealed. The user selects a pre-existing cycle or programs new parameters using the touch screen. If the sterilizer has a safety-locking mechanism, this is automatically engaged as soon as the cycle begins. It will not release until the load has finished processing and cooled to a safe temperature.
A vacuum pump removes the air from the chamber. Heated steam is introduced into the autoclave via an external pipeline or from a steam generator that is integrated in the sterilizer. The pressure inside the autoclave is increased, and the temperature quickly begins to rise. When the steam reaches 121 degrees Celsius, this temperature is maintained for 15 minutes.
The steam is then removed from the chamber and heated air is used to dry the load. For wrapped instruments, a post-vacuum cycle may be required to aid in the drying process. Next, pressure is normalized and the load is allowed to cool. The chemical indicator can be checked immediately to verify that the appropriate temperature was reached during the cycle. The biological indicator must be cultured to see if any microbes remain alive. Many autoclaves have microprocessors and a data storage unit that can display and/or archive the information for each cycle.
Wet loads are a common problem in many sterile processing departments. If moisture is detected in a load at the end of a cycle, it is not considered sterile, and it must be reprocessed. Technicians can reduce the frequency of these wet loads by using proper loading and wrapping techniques. If a tray of hot instruments is removed from the autoclave too soon, moisture from the air (contaminated with germs) immediately begins to form as condensation on the exposed surfaces. Ensuring that the drying and cool-down portions of the cycle are not cut short can prevent this problem.