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Sterilization: How, When and What With |
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By Pauline W. Fallis
R.N., B. Admin. (HS), C.I.C. Infection Control Consultant
NOSO Health Care Inc. 22 Maple Grove Avenue Station B
Richmond Hill.
Ontario
L4E 2V1
Phone/ Fax: 1-905-773-4400
In the last ten years, bloodborne pathogens (germs contained in blood that
cause disease) have become a concern. Until that time, we did not know of
the Human Immunodeficiency Virus (HIV), which as we all know is the virus
that causes AIDS. And with the large population immigrating to tile western
world from South East Asia the Hepatitis B virus (HBV) which is common
there is now a problem. This virus causes diseases of the liver, that often
progress from simple inflammation to cancer. Both these viruses are found
in high concentrations in the blood. Both these viruses are transmitted by
blood to blood contact and cause life threatening diseases. As an
electrologist, you must be aware that you are dealing with blood, and that
your instruments may be a vehicle for the transmission of diseases like
AIDS and Hepatitis B. You must sterilize your instruments between clients.
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 Company.
INFECTION CONTROL ARTICLES
- PREPARING FOR THE PATIENT/CLIENT
Spring 2001, Volume 8, Number 1
- PREVENTING INFECTION FOR ELECTROLYSIS
Fall 2000, Volume 7, Number 2
- INFLUENZA
Spring 2000, Volume 7, Number 1
- MICROORGANISMS AND INFECTIOUS DISEASE
Summer 1999, Volume 6, Number 2
- BLOOD BORNE INFECTIOUS DISEASES AND PERSONAL PROTECTION
Spring 1999, Volume 6, Number 1
- MICROORGANISMS & INFECTION
Fall 1998, Volume 5, Number 2.
- BIOLOGICAL TESTING OF YOUR STERILIZATION PROCESS
Spring 1998, Volume 5, Number 1
- STEAM STERILIZATION
Fall 1997, Volume 4, Number 2
- CHEMICAL STERILIZATION
Spring 1997, Volume 4, Number1
- DRY HEAT STERILIZATION
Fall 1996, Volume 3, Number 2
- STERILIZATION
Spring 1996, Volume 3, Number 1
- IS YOUR USE OF NEEDLES SAFE IN YOUR PRACTICE?
Fall 1995, Volume 2, Number 2
- PREPARING INSTRUMENTS FOR STERILIZATION
Spring 1995, Volume 2, Number 1
- WHY ARE GLASS BEAD STERILIZERS NOT RECOMMENDED FOR USE IN ELECTROLOGY?
Fall 1994, Volume 1, Number 2
- STERILIZATION: HOW, WHEN, AND WHAT WITH
Spring 1994, Volume 1, Number1
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