| A direct path must be
maintained between the filter and the area inside the hood where
the manipulations are being performed. Air downstream from
non-sterile objects (such as solution containers, hands etc.)
becomes contaminated from particles blown off these objects. To
best illustrate this very important point click on the two
examples of proper aseptic technique: (manipulation of a vial and
an ampoule).
The hands should never obstruct airflow around the area where the
needle enters the vial or ampoule. Also, when pulling back the
plunger of a syringe, the fingers should not come in contact with
any part of the plunger--except the flat part at the end. Poor
manipulation of the syringe is the most frequent cause of
contamination.
Always minimize clutter. Waste and other items
should never enter the hood. All calculations should be done
before entering the hood.
Wash hands and arms before compounding or
re-entering the hood. Also, remove any jewelry from the hands and
wrists. It is important that you keep your hands within the
cleaned area of the hood as much as possible. Do not touch
your hair, face or clothing.
Excess dust should be removed from items before
introducing them into the hood.
Arrange objects in a manner to get full benefit
of the laminar flow of air. Critical items should be placed as close to
the air source as possible. In a horizontal hood, items
should be placed no closer than 3 inches from the very back of the
hood (nothing should touch the filter). Occasionally, you may
stack a few items (eg IVPB's), however they must be stacked from lower
to higher starting from the back
of the hood. Also, it should be limited to a maximum of 3 to 4
items.
When working in a horizontal laminar flow hood,
all work must be performed at a distance of no less than 6
inches from the front edge of the work surface. At a distance of
less than 6 inches, laminar flow air begins to mix with the
outside air and contamination is possible. Never become so
engrossed in your work that you forget this basic rule.
Avoid spraying or squirting solutions onto the
HEPA filter. Always aim away from the filter when opening ampoules
or adjusting syringes.
Outer pouches and wraps should be removed at the
edge of the work area as the sterile contents are pulled into the
work area. Never bring these items into the main work area.
Large objects should never be placed near the
back of the hood. Not only do these objects contaminate everything
downstream, but they also disrupt the laminar flow pattern of air
which normally suspends the contaminants and removes them from the
area.
Remember that hand cleanliness is further
reduced each time more bottles and other non-sterile items are
handled.
Before and after preparing a series of IV
admixtures, or anytime something is spilled, the work surface of
the laminar flow hood should be thoroughly cleaned with
alcohol. A long side to side motion should be used starting
at the back of the hood and then working forward. The acrylic
plastic sides should also be cleaned periodically.
It is possible to overcome the established
airflow velocity by a strong reverse current produced by coughing,
quick movements, talking etc. Keep all of these to a minimum
in order to maintain a sterile environment. Do not talk, cough or
sneeze into the hood! The contents of
glass ampoules should always be filtered before adding to an IV
admixture. Needles should be used for a
maximum of 8 to 10 punctures. It may be necessary to change the
needle more frequently if it becomes increasingly difficult to
enter a vial. Always disinfect all rubber
stoppers and ampoule necks with alcohol before entering with a
needle. |
