Page 176 - Assurance of Sterility for Sensitive Combination Products and Materials

158 Assurance of sterility for sensitive combination products and materials

intermediate-level disinfection. High-level disinfection is appropriate for
semi-critical devices. These devices contact intact mucous membranes.
Critical medical devices require sterilization.
Chemical and physical disinfectants work by contact; the disinfectant
must contact the surface of the medical device for the stated time and at
the stated dilution for disinfection to occur. High-level disinfection can
also be accomplished with heat. Some washer-disinfector machines provide
thermal disinfection.
The efficacy of a chemical or physical disinfectant can be affected by
many things. Organic material on a device can prevent the disinfectant
from contacting the device surface. The presence of extremely high num-
bers of microorganisms may require more than the stated time to provide
the kill. Different types of microorganisms can have differing resistance to
the disinfectant, e.g., bacterial spores will be resistant to all but high-level
disinfectants. Devices, such as duodenoscopes, that require high-level disin-
fection have been associated with a high risk of infection if the item is not
adequately cleaned.

Sterilization at the HCF
Medical devices that enter sterile tissue or the vascular system or through
which blood flows must be sterile when used. Most reusable medical devices
sterilized in HCFs are heat stable and can be sterilized with heat, usually
steam sterilization. Some devices require low-temperature sterilization and
cannot be sterilized by steam. Low-temperature sterilization processes in-
clude: ethylene oxide (EO), hydrogen peroxide gas plasma, vapor-phase hy-
drogen peroxide, peracetic acid immersion, and hydrogen peroxide/ozone.
Meticulous cleaning of medical devices is required before sterilization.
Sterilization processes must be validated by the manufacturer of the device.
HCF must follow the sterilization process that was validated by the manu-
facturer and perform verification each time that the process is run. HCFs
should also perform product quality assurance (PQA) testing on all devices
sterilized by the HCF. PQA testing involves testing of routinely processed
items that represent a product family. It is intended to verify that the process
being used by a particular facility for a particular product family is working
as specified. PQA testing is used to verify that the device manufacturer’s IFU
works in the HCF using the cleaning and sterilization equipment available.
Steam under pressure Moist heat under pressure sterilization is the
most widely used and the most dependable sterilization process used in
HCFs today. This process is nontoxic, inexpensive, rapidly microbicidal,