Presented by Nida J. Salcedo
ADON – Operating Room
There is no degree of sterility. An item
is either sterile or non-sterile. It can
never be relatively sterile.
STERILIZATION – is the process by
which all living micro-organisms both
pathogenic and non-pathogenic
including spores are killed.
• The prevention of surgical site infection in
health care areas is largely dependent on
the rigorous adherence to the principles
of aseptic techniques by all personnel
who performs any invasive procedures on
patients, the sterility of all items directly
used in such procedures and the
disinfections of all surfaces and other
items in the immediate environment.
• Surgical instruments, linen and heat
sensitive items are sterilized by the
method recommended by the
manufacturer. No disposable items
designed for sterile single use
should be processed.
It is essential for a sterilizing
agent to be in contact with every
surface of each item or device to
be sterilized for the specified
period of time at the specified
A. Physical Methods:
Heat – is the earliest, the safest and
surest method of sterilization. It
may be dry (hot air ovens infra red
conveyor ovens) or moist (steam).
• Dry heat, at normal atmospheric
– Hot air ovens – these are electrically heated
and usually with an internal fan to provide
and even distribution of heat. Sterilizing time
is one hour at 160ºC. This is suitable for
ophthalmic instruments, glassware and
– Infra red conveyor oven – items are passed
on a conveyor through a tunnel heated by
infra red elements. The infra red radiation is
lethal so it is not commonly used now days.
• Moist heat, at a raised atmospheric
– Steam autoclave (steam under pressure)
Steam sterilization is the most inexpensive
and effective method of sterilization. Steam
under pressure permits permeation of moist
heat to porous substances by condensation
and results in destruction of all microbial life.
This is the usual method of sterilizing
surgical instruments, dressing, drapes,
swabs, laps sponges and culture media.
WHAT IS AN AUTOCLAVE?
• An autoclave is a closed chamber in
which items or objects are subjected to
steam at high pressures and
temperatures above 100ºC. Steam is a
more efficient method of sterilization than
air at the same temperature. If air is
present in the sterilizing chamber, a
satisfactory temperature will not be
achieved and pockets of air may prevent
penetration of the load of articles by the
steam. The air must therefore be
TYPES OF AUTOCLAVES
• DOWNWARD DISPLACEMENT
AUTOCLAVES – Air is removed in two
stages and sterilization is effected by an
atmosphere of pure steam.
• The minimum exposure time is required
for sterilizing instruments is 50 minutes
at 131ºC or 60 minutes at 136ºC. Bulky
dressings, surgical swabs and surgical
drapes require exposures two or three
times as long.
• HIGH VACCUM / HIGH PRESSURE
AUTOCLAVE – Air is removed by
powerful pump. Steam penetrate the
load instantaneously and very rapid
sterilization of dressings, instruments,
raytec swabs, lap sponges and packs is
possible in 15 to 30 minutes at 134ºC.
Some causes of failure to
produce a sterile load are:
Faults in the autoclave and the way it
– Poor quality steam
– Failure to remove air and condensate
– Faulty gauges and timings
– Leaking door seals
Errors in loading
– Large packs
– Excessive layers of wrapping
– Over packing
Recontamination after sterilization due
– An inadequate air filter and leakage
into the chamber
– Wet or torn packs
– Incorrect storage
THE STEAM STERILIZATION PROCESS
WHICH IS DIVIDED IN TO FIVE DISTINCT
The loading phase - in which the objects or
items are packaged and loaded in the
The heating phase – in which the steam is
brought to the proper temperature and
allowed to penetrate around and
through the objects in the chamber.
The destroying phase – or the time-temperature
cycle, in which all microbial life is exposed to the
killing effect of the steam.
The drying and cooling phase – in which the
objects are dried and cooled, filtered air is
introduced into the chamber, the door is opened
and the objects are removed and stored.
Testing phase - in which the efficiency of
the sterilization process is checked. All
mechanical parts of sterilizers, including
gauges, steam lines and drains, should
be periodically checked by a competent
MAKING OF STERILE
Packages/Instrument Sets should have the
following external indications, showing that
they have been processed:
• Autoclave tapes that show a package has been
through a sterilization cycle should be visible on the
outside of every package sterilized. The autoclave tape
is designed black when a certain temperature inside the
autoclave is reached. This is usually at 120ºC to 135ºC
depending upon the length of the selected time cycle.
• Every package must be labeled as to its contents and
• Every package, tray or item is to be labeled with the
processing date, autoclave used and load number. This
will assist locating processed items in case of recall.
PREPARATION OF ITEM
6. Loading in sterilizer
STORAGE OF STERILE
• Sterile packages/items should be
left untouched and allowed to be
cooled before storage to avoid
condensation inside the packs.
• Sterile packages must be handled
as little as possible to reduce the
risk of contamination.
• Sterile packages should be stored
on open shelves.
– The lowest shelf should be 8 inches
from the floor
– The highest shelf should be 18 inches
from the ceiling
– All shelves should be at least 2
inches from the walls
• Sterile packages must be stored and
issued in correct order.
• Sterile items are good for either 30
days or 6 months depending solely on
how the packages are wrapped and
what type of wrappers are used. This is
called the shelf life which refers to the
length of time a package maybe
• The storage room must be
subjected to adequate pest
control to prevent contamination
from rodents, ants and
• Traffic is restricted to CSSD
personnel and trainees only.
METHODS OF TESTING THE
EFFECTIVENES OF AUTOCLAVES
ARE AS FOLLOWS:
1. BOWIE DICK TEST PACK – It is a
large pack with a chemical
indicator both on outside and the
inside to verify that steam has
penetrated the pack.
2. MECHANICAL- Chart and gauges
usually carried out by Biomed
3. CHEMICAL- by the use of autoclave
tapes, strips and card. A daily test in
an empty chamber using a heat
sensitive tape. This is for high
vacuum/high pressure autoclaves.
Ex. Routine use of Browne's TST
strips or tube.
4. BIOLOGICAL- indicators of live
organism. It is the microbiological
monitoring of sterilizers and is
recommended at least once a week with
commercial preparation of spores of
formerly Bacillus Stearothermophillus.
This microorganism is having spores that
are particularly resistant to moist heat
thus assuring a wide margin of safety.
TESTING THE EFFECTIVENESS
OF THE STEAM AUTOCLAVE:
First- They run it empty for one cycle.
Second- They put inside in the middle of the
chamber of the SA the Bowie Dick Test
Pack and run it again and finish the
whole cycle. Oh high pressure- to test
leaks and presence of air.
Third They load it with items and trays for
sterilization ( little bit lower pressure). It
is done once daily.
Fourth- Live Organism- done once in every
HIGH SPEED STERILIZATION –
Referred to as a FLASH STERILZER
• This high speed steam sterilizer is adjusted to
operate at 132ºC (270ºF) and 27 PSI for 3
minutes. It is most frequently used in the OR for
the urgently needed unwrapped instruments. It
should be used only when time does not permit
sterilization of unwrapped sets.
• Implantable devices are not recommended to
be flash sterilized because the reliability of
sterilization is reduced by the speed of the cycle.
Spore tests cannot be used reliably and the
margin of safety is lower.
B. COLD METHOD
• Gaseous Sterilization
• a. Ethylene Oxide (EO) – This is a
well established technique for
sterilizing heat labile articles. It is
colorless at ordinary temperatures,
has an odor similar to that of ether
and has an inhalation toxicity similar
to that of ammonia dioxide or
fluorinated hydrocarbons (FREON).
• It can be used for sterilizing vascular and bone
grafts, delicate instruments, plastic articles such
as disposable syringes, surgical instruments
such as cystoscopes, catheters, bacteriological
media and vaccines.
• Before EO sterilization, objects also need to be
cleaned thoroughly and wrapped in a material
that allows the gas to penetrate.
• Chemical indicators for EO should be used with
each package to show that it has been exposed
to gas sterilization process.
• Gas sterilizers are recommended to be checked
at least once a week with commercial
preparation spores, usually Bacillus Atropheus
formerly BACILLUS SUBTILIS VAR. NIGER.
• All objects processed by gas sterilization also
need special aeration according to
manufacturer’s recommendation before use to
remove toxic residues of EO.
• In general, an exposure period of 3 to 7 hours is
necessary for complete sterilization.
Temperature for sterilizing is 21º C to 60º C 70º
F to 140º F).
• Materials aerated in a mechanical
aerator that provides a minimum of
four air changes per hour and
elevates the temperatures within the
cabinet to 50º C to 60º C (122º F to
140º F) require 6-8 hours of aeration
based on the composition of the
sterilized items and the aerator
ADVANTAGES OF EO:
• EO sterilization should be used only if
materials are heat sensitive and unable to
withstand sterilization by saturated steam
• EO is easily available and is effective
against all types of microorganisms.
• EO easily penetrates through masses of
dry materials; does not require high
temperatures, humidity or pressures.
• EO is non- corrosive and non- damaging
DISADVANTAGES OF EO:
• It is lengthy process in the long exposure and
• EO sterilization is expensive and more complex
• Liquid EO may produce serious burns on
exposed skin if not immediately removed.
• Insufficiently aerated materials can cause
irritation, burns of body tissues, hemolysis of
blood and diluents used with EO cause damage
to some plastics.
• It is toxic and can cause Cancer. Precautions
should be taken to protect personnel.
• b. Gamma Radiation
This involves the use of gamma radiation from a
Cobalt 60 source and is used commercially.
• c. Ultraviolet light
This is a form of surface radiation and its
penetrating capacity is poor, so it is used for
sterilizing surfaces, bone chips, grafts and
• d. Plasma (Sterrad)- Autoclave -
Low Temperature Hydrogen Gas
Sterilizers. It is used to sterilize
delicate instruments. Spore testing
should be performed at the same
interval as testing of other sterilizers.
2. LIQUID CHEMICAL
• When used properly liquid chemo
sterilizers can destroy all forms of
microbial life including bacterial and
fungal spores, tubercle bacilli and
• Liquid chemicals can be used for
sterilization when steam, gas or dry
heat is not indicated or available.
Liquid Chemicals that are capable
of causing sterilization
– Aqueous Formaldehyde- is one of the oldest
chemo sterilizers known to destroy spores; it is rarely
used because its pungent odor is objectionable.
– Aqueous Glutaraldehyde- is more rapid and
less irritating than formaldehyde solutions. Instruments
must be free of bioburden and completely immersed in
activated aqueous glutareldehyde solution for 10 hours
to achieve sterilization. During immersion all surfaces
of the instruments must be rinsed thoroughly with
sterile distilled water before being used. Any period of
immersion less than 10 hours will not kill spores that
may be present and must be considered as only a
• Thank You Very Much for Listening