Decontamination and Cleaning

Objectives KEY CONCEPTS you will learn: Why decontamination and cleaning are important initial steps in processing soiled items How effective decontamination and cleaning are How to prepare dilute chlorine solutions for decontamination How to decontaminate and clean instruments

Laboratory Unit

Instrument Processing Decontaminate Clean Sterilize Chemical High-pressure steam Dry heat High-Level Disinfect Boil Steam Chemical After use, instruments and other items should be decontaminated by soaking in a 0.5% bleach solution for 10 minutes. (Decontamination will help protect the person who is cleaning the instruments.) Then, physically wash the items until they are visibly clean. Finally, either sterilize or high-level disinfect the instruments. For a step-by-step description of this process, see the document “Instrument Processing” on the Resources page. Dry/Cool and Store

Processing Instruments and Other Items Decontamination makes inanimate objects safer to be handled by staff before cleaning. Cleaning physically removes all visible dust, soil, blood or other body fluids from inanimate objects. Decontamination is the first step in processing soiled (contaminated) surgical instruments, gloves, and other items, especially if they will be cleaned by hand (Nyström 1981). For example, briefly soaking contaminated items in 0.5% chlorine solution, or other locally available disinfectants, rapidly kills HBV[1] and HIV, thereby making the instruments and other items safer to be handled during cleaning (AORN 1990; DHMH 1990; Lynch et al 1997). Larger surfaces, such as examination and operating tables, laboratory bench tops and other equipment that may have come in contact with blood or other body fluids also should be decontaminated. Wiping with a suitable disinfectant (e.g., 0.5% chlorine solution or 1–2% phenol) is a practical, inexpensive way to decontaminate them. After instruments and other items have been decontaminated, they need to be cleaned and finally either sterilized or high-level disinfected (Lynch 1997; Rutala 1993; Tietjen and McIntosh 1989). [1] Throughout this manual, when hepatitis B (HBV) is mentioned, hepatitis C (HCV) and Delta hepatitis (HDV) also are referred to because their occurrence is worldwide and mode of transmission or prevention is similar.

Processing Instruments and Other Items (continued) High-level disinfection eliminates all organisms (bacteria, viruses, fungi and parasites) except some endospores. Sterilization eliminates all organisms including bacterial endospores. When Is Sterilization Absolutely Essential? When Is HLD an Acceptable Alternative? Most authorities recommend sterilization as the final step in processing instruments and other items used for surgical procedures. Some guidelines, however, are more flexible and state that when sterilization equipment is not available, HLD can be used. In fact, the use of sterilization is not possible or practical in certain situations (Rutala, Weber and HICPAC 2002). For example, laparoscopes, which would be damaged if submitted to either high-pressure steam (autoclaving) or dry heat sterilization, usually are processed between cases by HLD (i.e., soaking in a chemical high-level disinfectant for 20 minutes). When correctly performed, sterilization clearly is the safest and most effective method for the final processing of instruments. If it is neither available nor suitable, however, HLD is the only acceptable alternative for final processing. High-level disinfection kills all microorganisms but does not reliably kill bacterial endospores. Staff must be aware of this limitation if tetanus, a disease caused by endospores produced by bacteria called Clostridium tetani, is a significant risk.

Table 10-3: Effectiveness of Methods for Processing Instruments Effectiveness (kill or remove microorganisms) End Point Decontamination Kills HBV and HIV and most microorganisms 10-minute soak Cleaning (water only) Up to 50% Until visibly clean Cleaning (water and soap) Up to 80% Sterilization 100% High-pressure steam, dry heat, or chemical High-Level Disinfection 95% (does not inactivate some endospores) Boiling, steaming, or chemical for 20 minutes

Decontamination Principles: Inactivates HBV and HIV Makes items safer to handle Must be done before cleaning

Decontamination Practices Place instruments and reusable gloves in 0.5% chlorine solution after use. Soak for 10 minutes and rinse immediately. Wipe surfaces (exam tables) with chlorine solution. Decontamination Principles: Inactivates HBV and HIV Makes items safer to handle for the staff cleaning them

IP: Instructions for Preparing Dilute Chlorine Solutions Total parts (TP) (H2O) = - 1 Total parts (TP) (H2O) = - 1 = 9 Total parts (TP) (H2O) To make a 0.5% chlorine solution from 5% bleach, mix 1 part bleach to 9 parts water.

IP: Instructions for Preparing a Chlorine Solution from a Powder Gram/Liter = X 1000 Gram/Liter = X 1000 = 14.2 Gram/Liter To make a 0.5% chlorine solution from a 35% chlorine powder, mix 14.2 grams of powder to 1 liter of water.

Examples Using 5% Bleach for 0.5% Concentration One part bleach to 9 parts water (use the same container to measure the bleach and water)

Household Bleach Safety Use mask, goggles, rubber gloves, waterproof apron Mix in well-ventilated area Do not use or mix with other detergents Use cold or room temperature water to mix When preparing or using bleach solutions, you should wear a mask, rubber gloves, and a waterproof apron. Goggles are also recommended. And you should mix the solution in a well-ventilated area. Do not use your bleach solution with or mix with other household detergents. This may reduce its effectiveness or cause chemical reactions. For example, mixing bleach with acidic agents can produce toxic gas.

Factors Influencing the Efficacy of Disinfection/Sterilization Cleaning of the object Organic and inorganic load present Type and level of microbial contamination Concentration of and exposure time to disinfectant/sterilant Nature of the object Temperature and relative humidity

Cleaning Principles: Removes organic material that: Protects microorganisms against sterilization and HLD Can inactivate disinfectants Must be done for sterilization and HLD to be effective Method of mechanically reducing the number of microorganisms, especially endospores

Cleaning Practices after items are decontaminated: Wash with detergent, water, and a soft brush. Disassemble instruments. Scrub instruments under the water surface until visibly clean. Thoroughly rinse with clean water. Use PPE during cleaning. Cleaning Principles: Removes organic material that: Can protect microorganisms against sterilization and HLD Can inactivate disinfectants Must be done for sterilization and HLD to be effective Method of mechanically reducing the number of endospores

Cleaning and preparing for sterilization

Kitchen Utensils Washing Area