33.  Cleaning, sterilization, and maintenance

Following a medical procedure, any reusable invasive medical devices used is classified as contaminated. These devices must be reprocessed in a hospital’s central sterile supply department using automated decontamination equipment that is validated to international standards. Contaminated devices should be washed manually to remove any organic matter. Disinfection can be carried out to three levels: high, medium, and low. Medical devices that are deemed invasive must be reprocessed using high level disinfection. With the chemical agents used and the temperatures achieved in the washer disinfectors this is classed as a high-level disinfection. Disinfection is a process that kills or inactivates microorganisms. It does not eliminate all microorganisms but reduces them to safe levels for handling. Disassembled and opened medical devices that have successfully passed a high level disinfection cycle should be inspected for functionality to ensure that the item still works correctly. Once these visual checks have been completed, the medical device must be sterilized. Sterilization is a process that destroys all living microorganisms, including bacteria spores. It renders the medical device free from viable organisms. The most rapid and effective way of killing microorganisms is with moist heat. This is achieved by exposing microorganisms to steam, generated to a temperature of 134 °C for three minutes under pressure of 2.1 bar in a sealed chamber, commonly referred to as an autoclave. There are also a number of other methods of sterilization, including dry heat sterilization, gas sterilization, chemical sterilization, and radiation sterilization.