| There are several reasons for sterilization failure:
Incorrect loading of the sterilizer - This
is the #1 reason for sterilization failure. Instruments should
be placed in the sterilizer in a single layer or placed on
edge and loosely loaded for complete circulation of the sterilant.
Items packed too tightly together will not allow complete
penetration of the sterilant to the center of the load. Sterilizer
manufacturers' instructions should be strictly followed regarding
the size of the load or number of instruments placed in the
chamber. It is far too easy to be tempted into saving time
by putting in one more package. That one extra can cause the
sterilization failure.
Inadequate cleaning of instruments - Both
visible and invisible debris left on instruments will prevent
complete surface contact with the sterilant. This is the only
cause of failure that cannot be detected by sterilization
monitoring. Therefore, decontamination procedures that include
meticulous cleaning and inspection of instruments must be
in place and strictly adhered to by everyone.
Improper packaging - Selecting a pouch that
is too small for the number of instruments going into it will
not allow complete circulation of the sterilant around the
instruments. Using packaging not compatible with the sterilization
process will also impede penetration of the sterilant. Solid
metal containers should never be completely closed or the
sterilant will not get inside the container and using too
many layers of wrap may prevent the sterilant from penetrating
to the instruments.
Processing instruments in a cold sterilizer -
A cold sterilizer takes much longer to come up to temperature,
since it must heat the chamber in addition to the contents,
and may not adequately sterilize items. Run a cycle with an
empty chamber before the first load is processed.
Selecting the wrong sterilization cycle -
Sterilizers with automatic cycle vs. manual time and temperature
selection can sometimes be confusing. If a load contains both
wrapped and unwrapped items, the "wrapped" cycle
should be chosen. Always select the longer cycle when sterilizing
mixed loads.
Selecting the wrong time or temperature -
Sterilizers that require manual selection of time, temperature
and/or pressure must be used according to manufacturers recommendations
for optimal results. The sterilant must have enough time for
the sterilant to adequately penetrate items in the load and
high enough temperature to kill all organisms. Pressurized
sterilizers must come up to the correct pressure in order
for sterilization to occur.
Aborting the sterilization cycle - Aborting
a cycle in order to use instruments more quickly or opening
a sterilizer during a cycle to add instruments will likely
result in sterilization failure. Even though it may save
time, DO NOT abort the sterilization cycle before it is complete,
including drying time. Remember, a wet instrument or package
is contaminated as soon as it hits ambient air or is touched.
If extra instruments must be added to a load in process, restart
the cycle.
Sterilization monitoring - The dials, gauges
and printouts can indicate only instances of gross mechanical
failure. They cannot tell you what is happening within the
load. The use of chemical and biological indicators is recommended
by several organizations such as CDC (Centers for Disease
Control and Prevention), ADA (American Dental Association),
OSAP (Office Safety and Asepsis Procedures Research Foundation),
AAMI (Association for the Advancement of Medical Instrumentation),
etc. Their recommendations include:
- Process indicators on the outside of
every package which, through color-changing ink, will differentiate
between processed and unprocessed items
- Internal indicators or integrators on
the inside of every package. An internal indicator will
demonstrate, through a color-changing ink or melting pellet,
that adequate temperature was present inside as well as
outside the pouch. An integrator (or multi-parameter indicator)
will demonstrate time and temperature in the presence of a
specific sterilant using either color-changing ink or a
wicking device.
- Biological indicators used on a weekly
basis, in every ethylene oxide cycle and in every load of
implantable items to demonstrate, thorough destruction of
highly resistant bacterial endospores, that all the parameters
necessary for sterilization to occur were met, including
time, temperature, sterilant and humidity.
|
