Do not add anything to or remove anything from the pot/boiler once boiling begins. 92 · A white, scaly deposit may be left on instruments and other items that have been boiled frequently and on the pot/boiler itself. These are lime deposits caused by lime salts in the water. · To minimize lime deposits: · Add some vinegar to the water to remove deposits from instruments, other items, and the inside of the pot/boiler. · Boil the water for 10 minutes at the beginning of each day that the pot/boiler is used; this will precipitate the lime (make it come out of the water and settle on the bottom or sides of the pot/boiler instead of on the instruments or other items) before the instruments or other items are added. · Use the same water throughout the day, adding only enough to keep the instruments and other items below the surface. · Drain and clean out the pot/boiler at the end of each day that it is used. 92 . · A high-level disinfected tray or container can be prepared either by: – Boiling it for 1 minute and drying thoroughly, or – Filling it with a 0.5% chlorine solution and letting it soak for 20 minutes, draining the chlorine solution, and rinsing thoroughly with boiled water. · Stainless steel containers are preferred as containers for HLD. HLD by mechanical – thermal disinfection Disinfection by hot water can also be performed in specially constructed washing machines (e.g., for linen, dishes and cutlery). In these machines the processes of cleaning, of hot water disinfection, and of drying are combined in a very effective procedure, providing some items ready for use (e.g., respiratory circuits) or safe to handle (e.g. surgical instruments). The thorough initial rinsing and washing removes most of the microorganisms and shorter disinfection times. If machines are used they should be regularly maintained and checked for efficacy.Cleaning, Disinfection, and Sterilization of Medical Equipment 148 Low to high-level disinfection is achieved depending on type of machine and complexity of the items. 31 Chemical HLD Before deciding to use a chemical disinfectant, consider whether a more appropriate method is available. Chemical disinfection is used most commonly for heat-labile equipment (e.g. endoscopes) where single use is not cost effective. A limited number of disinfectants can be used for this purpose. e.g.: · Glutaraldehyde 2% for 20 min., · Hydrogen peroxide 6% – 7.5% for 20 – 30 min., · Peracetic acid 0.2-0.35% for 5 min. · Ortho-phthalaldehyde (OPA) for 5-12 min. The object must be thoroughly rinsed with sterile water after disinfection. If sterile water is not available, freshly boiled water can be used. After rinsing, items must be kept dry and stored properly. Steps: 1. Clean and dry all items to be high-level disinfected. Water from wet instruments and from other items dilutes the chemical solution, thereby reducing its effectiveness. 2. When using a glutaraldehyde solution: Preparations of glutaraldehyde are non-corrosive to metals and other materials and inactivation by organic matter is very low. Alkaline solutions require activation; once activated they remain active for at least 2 weeks depending on the frequency of use.
If the solution is not activated prepare it in a sterile container by following the manufacturer’s instructions. Fresh solution should be made each day (or sooner, if the solution becomes cloudy). 3. If using a previously prepared solution, use an indicator strip to determine if the solution is still effective. If preparing a new solution, put it in a clean container with a lid and mark the container with the preparation date and expiration date. 4. Open all hinged instruments and other items and disassemble those with sliding or multiple parts; the solution must contact all surfaces in order for HLD to be achieved. 5. Place all items in the solution so that they are completely submerged. Place bowls and containers upright, not upside-down, so that they fill with the solution. 6. Cover the container and allow items to soak for 20 minutes. During this period, do not add or remove any items from the container. Monitor the time.Cleaning, Disinfection, and Sterilization of Medical Equipment 149 7. Remove the items from the container using, dry, high-level disinfected pickups (e.g., forceps). 8. Rinse thoroughly with boiled water to remove the chemical residue that is left on items.