Thermal and Chemical Disinfection Methods

Reprocessing Medical Devices

• High-level disinfection is the minimum treatment recommended for reprocessing medical devices that cannot be sterilized, used for semicritical sites or when there are specific concerns regarding contamination of surfaces.
• Low-level disinfection is the minimum treatment recommended for reprocessing non-invasive medical devices for use in non-critical sites.

Drying

• Drying minimizes rusting, staining, and reduces the risk of recontamination during inspection and assembly of RMDs.
• Residual moisture interferes with the sterilization process.
• Methods for drying include using a clean disposable lint-free, absorbent wipe or a drying cabinet.

Process Chemicals

• Thorough cleaning of used surgical devices prior to sterilization is critical, and the main agent that affects cleaning is the process chemical used in the wash area of the CSSD.
• Factors to consider when handling chemicals include:
  • Storing chemicals below shoulder height
  • Making Safety Data Sheets (SDS) and labels available to staff
  • Training personnel who handle chemicals
  • Reading and following precautions and instructions given on the SDS and label

Water Quality

• The quality of water used at all stages in the cleaning process is critical to the successful outcome of the process.
• Unfavorable water compositions can have an adverse effect on the reprocessing process and on the devices themselves.
• Purified water rinse is used in the cleaning process.

Disinfection

• There are two types of disinfection: thermal and chemical.
• Thermal disinfection can be achieved in a thermal washer-disinfector by choosing the appropriate cycle.
• Chemical disinfection depends on factors including the initial number of microbes present, temperature, pH, and concentration.
• Chemical disinfection can be achieved with a compatible RMD-grade disinfectant of the required level, used alone or with a chemical washer-disinfector.
• Validation of chemical disinfection processes is done microbiologically, defining the concentration, contact time, and minimum/maximum temperatures for adequate disinfection.

Safety Precautions

• Chemicals such as detergents and disinfectants may have hazardous properties, including being irritant, corrosive, or flammable.
• Things to think about when dealing with process chemicals include choice of process chemicals, controls required, safety data sheets, and labeling.

Choice of Process Chemicals

• Choose process chemicals that are compatible with:
  • The medical device
  • The decontamination equipment to be used and the intended use of the device
• Choose the least hazardous chemical that will fulfill the process requirement.

Control of Process Chemicals

• Use defined, written procedures and methods for handling and storage of process chemicals.
• Clearly identify chemicals that should not be stored together.
• Consider factors such as pH, hardness, temperature, ionic contaminants, microbiological population, and bacterial endotoxins when using process chemicals.

Routine Testing of Decontamination Equipment

• Washer-disinfectors are subject to a schedule of periodic tests at daily, weekly, quarterly, and yearly intervals.
• These tests supply evidence that the washer-disinector is still operating within the limits established during commissioning.
• Tests include:
  • Daily: Spray arm rotation, spray nozzles, removes and clean strainers and filters
  • Weekly: Automatic control test, safety checks, water hardness, water conductivity, cleaning efficacy test