Final answer:
PCDs or test packs should be placed in the area most difficult for steam to penetrate and for air to be removed in non-tabletop steam sterilizers. In gravity displacement autoclaves, this is usually at the bottom of the sterilizer, while in prevacuum sterilizers, it's among or within packaged instruments.
Step-by-step explanation:
The placement of Process Challenge Devices (PCDs) or test packs in non-tabletop steam sterilizers is crucial for determining the effectiveness of the sterilization process. PCDs are designed to present the greatest challenge to a sterilizer's ability to achieve sterilization.
They should be placed in the area where it is most difficult for steam to penetrate and where air removal is most challenging. In gravity displacement autoclaves, which rely on steam introduced from the top or sides to displace the air, PCDs are generally placed near the bottom of the sterilizer where air is more likely to be present.
Conversely, in prevacuum sterilizers, which use a vacuum to remove the air, PCDs are located in the area that is most difficult for steam to penetrate, often among or within packaged instruments. The right placement ensures that if the PCDs are effectively sterilized, the entire load in the autoclave can be considered sterilized.