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What
is a washer/disinfector and what does it do?
A washer/disinfector cleans and
decontaminates dirty surgical instruments so they can be handled safely,
repackaged, and sterilized for a future surgery. The danger of handling instruments contaminated with blood is
obvious in this age of hepatitis, CJD and HIV.
The procedures for sterilizing instruments are based on years of
scientific testing of clean instruments.
If surgical instruments are not clean, the procedures are
ineffective. Dried blood on
instruments is hazardous to the employees of the hospital and to the next
surgical patient upon which the instruments are used.
The cleaning of dried blood is
much more difficult than cleaning dirt.
Blood coagulates, which means it goes from a free flowing liquid to
a solid that contains tough, microscopic fibers called fibrin.
These fibers are formed as the blood coagulates and jam themselves
into microscopic irregularities in the surface of the stainless steel
instrument. This is a
physical attachment to the surface through mechanical means, not just
chemical means as with traditional adhesives.
The action is similar to the roots of plants growing into cracks in
rocks, anchoring themselves to the surface.
The blood cells colored with hemoglobin are fairly easy
to wash off instruments but the clear fibrin material is much more
difficult. Thick droplets of
dried blood have so much fibrin, even the |
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colored hemoglobin can be trapped
and held in place.
Another thing that makes
blood difficult to clean is its ability to become insoluble when heated.
Heating causes blood to “denature.”
Denaturing is similar to eggs cooking in a frying pan.
Transparent uncooked egg whites are farily easy to wash away, but
opaque, cooked egg whites are much more difficult.
Dried, uncooked egg is even more difficult to wash away, just like
blood. The proteins in blood
are similar to albumin proteins in eggs.
What helps the cleaning of blood from instruments?
Water: Water will moisten dried blood
and make it possible to wash away. Avoid
dried blood by cleaning as soon as possible or keep instruments moist
while waiting.
Time:
With enough time, simple water will remove all types of blood.
Detergent: The
wetting ability of detergent will help water flow to all places in and
around the blood, even if water-repellent fats and oils are used.
Enzyme:
Enzyme cleaners break down long fibrin fibers, allowing water to
wash away the pieces…but time is needed for this action to take
place—approximately 10 minutes.
Temperature:
Low temperature to start (to prevent denaturizing) and higher
temperature later to maximize detergent cleaning efficiency. |
