In any practise that involves instruments and the human body, the subject of sterilization and disinfection must be addressed. It depends on the use of the instrument, to what degree you process. E.H. Spaulding categorized the objects into critical which are those items that enter the body such as needles and surgical instruments, semi-critical which are those items touching the mucous membranes of the body, and non-critical which are all other items. He went on to say that critical items must be sterile at the time they are used. Sem-critical items must be at least high level disinfected and non-critical items at least cleaned thoroughly or possibly low-level disinfected. Sterilization is a process which kills microorganisms or germs to prevent disease. Sterilization is necessary to ensure that when an object enters below the skin surface, it contains no disease causing microorganisms. Sterilization must also be used for those instruments that though they rarely go below the skin line, be- come contaminated with body fluids of clients. These fluids may include blood. Remember, if you have a small break in the skin, this is all a pathogen needs to enter the body to cause disease. To safeguard your clients, sterilize even your tweezers and other forceps. There are several methods of sterilization that are practical for you to use, they include steam under pressure, dry heat or chemical. But there are some rules that must be followed whatever the type of sterilizer, in order for sterilization to take place.
- All items to be steriIized must be cleaned of all visible soil and rinsed thoroughly or the sterilization process may not be effective.
- All surfaces must be exposed to the sterilant whether it is steam or chemical, thus all instruments with hinges must be open. This does not pertain to dry heat as there is no sterilant involved.
- The exposure time is critical, and in general the lower the temperature the longer the time. If the time is not long enough for the specified, sterilization will not take place.
- The temperature is also critical. And the temperature that you are sterilizing at must be maintained throughout the exposure time. This means that your chamber must reach the specified temperature before the timer starts.
- The standards indicate that table top sterilizers must be monitored with a biological indicator, to verify the sterilization process, at least weekly but preferably daily. The frequency to be determined by the number of loads completed per day. Record the results.
- Clean and maintain the sterilizer as per the manufacturer's instructions. As in any other mechanical device, when a sterilizer is kept clean and has regular preventative maintenance, its performance will remain consistent. It may even add to the longevity of the machine. There are several small table top steam sterilizers on the market and some are portable and can be transported from place to place if necessary. Steam sterilization is one of the cheapest as well as safest methods of sterilization. It may be used to process all items that are not heat or moisture sensitive. Steam sterilization is one of the processes that sterilizes only the surfaces of items. It is not the heat but the steam under pressure that sterilizes. The heat generated to produce the steam is not hot enough in itself to sterilize within the exposure time. There are chemical integrators available for monitoring each load of a steam sterilizer. This verifies that the time and temperature of the cycle have been met. Dry heat sterilizers come in two types, gravity or convection. Both types sterilize by heat. Heat sterilizes by coagulating the protein material in micro-organisms. The heat penetrates each item layer by layer, killing germs on its way. A gravity oven is essentially a standard baking oven. It has variations of temperature in different areas within the chamber just like your kitchen oven does. For sterilization to take place in all areas of the chamber, the minimum temperature must be in the coldest area in the machine. In order to effectively monitor a gravity oven make sure that the biological indicator is placed in that coldest area which is usually in the bottom front. On the other hand, convection ovens keep the temperature within the chamber constant throughout. The temperature is kept constant by the continual circulation of the air within the chamber. This makes for a reliable method of sterilization. Chemical sterilization can be done. But soaking in a germicide or disinfectant for 10 to 20 minutes is not enough. There are very few germicides that sterilize. And those that do, take extended periods of time to do the job. Like all other methods of sterilization, temperature is also important. At this time, the sterilants that have been proven effective are toxic and have caused some serious respiratory reactions. For instance, only use 2% gluieraideyde solutions in well ventilated rooms and keep the chemical in a closed container to reduce respiratory problems. It is anticipated that this chemical will be regulated for worker safety in the near future. All items sterilized with chemical sterilants must be thoroughly rinsed before use. Another effective chemical sterilant. peroxyacetic acid takes 12 minutes to sterilize This chemical must be used in a special sterilizing unit which not only sterilizes the item but also gives it four rinses. However, the unit is expensive. There is one other type of sterilizer available to you which uses a chemical in vapour form, to sterilize. The chemical is a combination of< 1% formaldehyde and alcohol. This type of sterilization is safe and effective but quite expensive. Remember, it doesn't matter which method you decide to use as long as you do sterilize your instruments. All the above methods of sterilization can be done in an office or utility room and need no special hook-ups as long as water and/or electricity are available. The choice is yours. REFERENCES Association for the Advancement of Medical Instrumentation, Steam Sterilization and Sterility Assurance in Office-Based, Ambulatory Care, Medical and Dental Facilities. (AAMI Recommended Practice), Arlington, Virginia, 1992. Association for the Advancement of Medical Instrumentation, Table-top Dry Heat (Heated Air) Sterilization and Sterility Assurance in Dental And Medical Facilities, Arlington, Virginia, 1992. Canadian Standards Association, Effective Sterilization in Hospitals by the Steam Process, Toronto, Ontario, 1991, CAN/CSA.-Z314.3-,91 Fallis, P.W., Infection Control In Office Based Health Care and Allied Services draft 111, Rexdale; 1994, Canadian Standards Association. Perkins, J., Principles and Methods of Sterilization in Health Sciences, Illinois, 1969, Charles C., Thomeas Publisher., Soule, B.M., ed., The Curriculum Committee of the Association for Practitioners in Infection Control, APIC Curriculum for Infection Control Practice, Vol. 1, Dubuque, Iowa. 1983, Kendall/Hunt Publishing Compan