STERILIZATION AND DISINFECTION OF SURGICAL INSTRUMENTS.pptx

STERILIZATION AND
DISINFECTION

Appropriate and Adequate
Instruments Processing
ANTISEPTICS AND DISINFECTANTS
An antiseptic is a chemical agent used on the
skin and mucous membrane to remove or kill
micro-organisms without causing damage or
irritation to the skin and mucous membranes.
May also prevent the growth and
development of micro-organisms.
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They are not meant to be used on inanimate
objects, such as instruments and surfaces.
Can be used for surgical hand scrub, skin
preparation as well as cervical and vaginal
preparation before a clinical procedure.
Disinfectants are chemical agents used to kill
micro-organisms on inanimate objects, such as
instruments and surfaces.
They are not meant to be used on the skin or
mucous membranes
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There are two types of disinfectants:
1. High Level Disinfectants
High level disinfectants kill bacteria, viruses, fungi
and some bacterial endospores.
Some high level disinfectants can be used to
sterilize equipment and if given sufficient time to
act, they are able to destroy bacterial endospores
that cause diseases such as tetanus and gas
gangrene. Bacterial endospores are difficult to be
kill because of their protective casing or coating.
They are also used for processing instruments
and other items.
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2. Low Level Disinfectants
Low level disinfectants kill most bacteria and
some viruses and fungi but do not kill
tuberculosis causing micro-organisms and
bacterial endospores.
They are used for cleaning surfaces such as
floors and countertops.
They should not be used for processing
instruments and other items.
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PRINCIPLES OF USING DISINFECTANTS AND ANTISEPTICS
 Clean the instruments first with soapy and clean water
 Choose chemicals that are effective on the suspected
or known micro – organism
 Choose chemicals that are stable and safe under
conditions of use
 Use freshly prepared detergents as much as possible
 Follow manufacturer’s directions
 Store chemical agents in compatible clean containers
which should always remain covered
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MEDICAL PERSONEL PRECAUTIONS WHILE USING
CHEMICALS
Equipment should be well prepared for
sterilization
Ensure the chemicals do not come in to contact
with your skin or mucous membranes
Fully immerse the equipment into the solution
Leave the instruments in situ for the
recommended time
The instruments should be removed by use of
forceps and cleaned in water or normal saline
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DISINFECTION
 Disinfection is the process, which involves the
elimination of most pathogenic microorganisms
(excluding bacterial spores) on inanimate objects.
 Chemicals used in disinfection are called
disinfectants.
 Different disinfectants have different target ranges,
not all disinfectants can kill all microorganisms.

Disinfectants are antimicrobial agents that are applied
to the surface of non-living objects to
destroy microorganisms that are living on the objects.
 Disinfection does not necessarily kill all
microorganisms, especially resistant bacterial spores; it
is less effective than sterilization, which is an extreme
physical and/or chemical process that kills all types of
life.
 Disinfectants are different from other antimicrobial
agents such as antibiotics, which destroy
microorganisms within the body, and antiseptics, which
destroy microorganisms on living tissue.
Disinfectants are also different from biocides — the
latter are intended to destroy all forms of life, not just
microorganisms.

Disinfectants work by destroying the cell wall of
microbes or interfering with their metabolism.
Sanitizers are substances that simultaneously
clean and disinfect.
Disinfectants kill more germs than sanitizers.
Disinfectants are frequently used in hospitals,
dental surgeries, kitchens, and bathrooms to kill
infectious organisms.
Bacterial endospores are most resistant to
disinfectants, but some viruses and bacteria also
possess some tolerance.

Importance of disinfection
• To minimize number of organisms in the population
worldwide.
• The method of disinfection is used internationally
for the safety of humans, to decrease the scale of
transmission of diseases.
• A large emphasis of sterilization and disinfection has
been placed in the food industry, water sanitization
and medical care and hospitals.
• As these have found to be largest affected
organizations with microorganisms and modes of
transmission amongst the population.
• Different disinfectants are used in different
industries, which target the specific flora.

Disinfection techniques are classified according
to:
1. Consistency
Liquid (Alcohols, Phenols)
• Gaseous (Formaldehyde vapor, Ethylene oxide)
2.Spectrum of activity
• High level
• Intermediate level
• Low level

3. Mechanism of action
• Action on membrane (Alcohol, detergent)
• Denaturation of cellular proteins (Alcohol,
Phenol)
• Oxidation of essential sulfhydryl groups of
enzymes (H2O2, Halogens)
• Alkylation of amino-, carboxyl- and
hydroxyl group (Ethylene Oxide,
Formaldehyde)
• Damage to nucleic acids (Ethylene Oxide,
Formaldehyde)

Commonn uses of disinfectants
Aldehydes: surface disinfection, fumigation of
rooms, chambers and operating theatres.
Alcohol: 70% aqueous alcohol is more effective at
microbial killing. 70% Ethyl alcohol is used as
antiseptic on skin.
Phenol:' first used by Lister to prevent infection in
surgical wounds. In high concentrations its used as
a disinfectant and in low concentrations as an
antiseptic.
Halogens: Iodine (antiseptic), Chlorine (bleach)

VIBRATIONS
Ultrasonic vibrations:
•With a frequency of > 20,000
cycle/second kills bacteria and some
viruses, when exposed for an hour.
Microwaves:
• Antimicrobial effect, disruption of cells
•Common uses: disinfection of
instruments and reduction of microbial
load. This method does not affect many
viruses.

Disinfectants can act on microorganisms in two
different ways:
 growth inhibition (bacteriostasis, fungistasis)
 lethal action (bactericidal, fungicidal or virucidal
effects).

STAGES OF THE MODE OF ACTION
 In an analysis of the action of a disinfectant, it
may often be difficult to distinguish between the
primary stage (characteristic of the mode of
action) and the secondary stage (merely a
consequence of the action).
 Action on the external membrane of the
bacterial wall A bacterium is protected from its
environment by a membrane, the integrity of
which is essential to survival of the bacterium.

. Action on the bacterial wall The bacterial wall is
important, as this confers rigidity and differs
considerably between Gram-positive and Gram-
negative bacteria. This diversity leads to great
variation in the affinities of the hydrophilic
disinfectants.
Action on the cytoplasmic membrane An active
molecule, such as a nutrient, may penetrate the
cytoplasmic membrane in the following ways:
a) passive diffusion (non-specific and slow)
b) active transport (specific, enabling the
accumulation of products in bacteria after either
transformation or binding to a membrane

Action on energy metabolism Some disinfectants acting on
adenosine triphosphatase (ATP)
Action on the cytoplasm and nucleus The disinfectant
mechanism may operate on the cytoplasm and nucleus at
the chromosome level.
Action on bacterial spores The impermeability and the
presence of dipicolinic acid in bacterial spores make these
forms much more resistant to disinfectants than vegetative
forms.
The active disinfectants include highly oxidising products,
such as hydrogen peroxide and chlorine, which can
destabilise this structure in spores

Mode of action of (chemical) disinfectants
• Adsorption on the microbes’ surface
• Diffusion through the surface
• Binding to the vulnerable sites (e.g. plasma
membrane, cytoplasmic proteins, nucleic
acids, and so on)
• Disruption of the vulnerable sites
• Injury and death of the microbes

Processing Instruments and Items
Instruments can be classified into the following categories:
Low Risk Instruments
 They come into contact with intact skin. Cleaning and
drying them is adequate e.g. thermometer
Intermediate Risk
They don’t penetrate the intact skin but come into contact
with mucous membrane eg endotrachea tube
High Risk
 They penetrate intact skin or sterile tissues. Require
cleaning and sterilization or high level disinfection where
sterilization is not applicable
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1.HIGH RISK
High risk items confer a high risk for infection if they
are contaminated with any microorganism.
Thus, objects that enter sterile tissue or the vascular
system must be sterile because any microbial
contamination could transmit disease.
This category includes surgical instruments, cardiac
and urinary catheters, implants, and ultrasound
probes used in sterile body cavities.
 Most of the items in this category should be
purchased as sterile or be sterilized with steam if
possible. Heat-sensitive objects can be treated with
EtO, hydrogen peroxide gas plasma;

2.Semi-critical Items(intermidiate risk)
Semi-critical items contact mucous membranes or
non-intact skin.
This category includes respiratory therapy and
anesthesia equipment, some endoscopes,
laryngoscope blades , esophageal manometry probes,
cystoscopes , anorectal manometry catheters, and
diaphragm fitting rings.
These medical devices should be free from all
microorganisms; however, small numbers of bacterial
spores are permissible..

Semicritical items minimally require high-level
disinfection using chemical disinfectants.
When a disinfectant is selected for use with certain
patient-care items, the chemical compatibility after
extended use with the items to be disinfected also
must be considered

3.NON-CRITICAL ITEMS(LOW RISK INSTRUMENTS)
Noncritical items are those that come in contact
with intact skin but not mucous membranes.
Intact skin acts as an effective barrier to most
microorganisms; therefore, the sterility of items
coming in contact with intact skin is “not critical.”
In this guideline, noncritical items are divided
into noncritical patient care items and noncritical
environmental surfaces.

Examples of noncritical patient-care items are
bedpans, blood pressure cuffs, crutches and
computers .
In contrast to critical and some semicritical
items, most noncritical reusable items may be
decontaminated where they are used and do not
need to be transported to a central processing
area.

Virtually no risk has been documented for
transmission of infectious agents to patients
through noncritical items when they are used as
noncritical items and do not contact non-intact
skin and/or mucous membranes.

Instrument processing entails three steps which
are:
Decontamination
Cleansing
Sterilization or high level disinfection.
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DECONTAMINATION
Is the process of elimination of pathogens except
the spore from inanimate things.
Is the first step in processing instruments and
other items for re-use.
Decontamination kills viruses and many micro-
organisms, making the instruments and other
items safe to handle by the staff who clean them.
Decontamination also makes instruments and
other items easier to clean by preventing blood,
other body fluids and tissue from drying on them.
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Decontamination is done by soaking instruments
and other items immediately after use, in a 0.5%
chlorine solution for 10 minutes immediately
after use.
OR use of endozime 4mls in 1 litre and soak the
instruments for 2 minutes
A container of this solution should be kept in
every operating room and procedure room so
that used items can be placed directly into the
bucket.
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CLEANSING
Is the removal of soil and organic material
from instruments and equipment used in
providing patient care
Is the second step in processing of equipment
It involves the use of water, mechanical agent
and sometimes detergent
Reusable objects are cleansed prior to
sterilization
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Steps for Proper Cleansing
Rinse object under cold water since warm
water causes proteins in organic material to
coagulate and stick
Apply detergent and scrub under running
water with soft – bristled brush
Rinse the object in water
Dry prior to sterilization
Note: Nurse should wear gloves, masks and
goggles during cleansing
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Factors Affecting the Efficacy of Disinfection and
Sterilization
1. Number and Location of Microorganisms
2. Innate Resistance of Microorganisms
3. Concentration and Potency of Disinfectants the more
concentrated the disinfectant, the greater its efficacy
and the shorter the time necessary to achieve microbial
kill.
4. Physical and Chemical Factors: temperature, pH, relative
humidity, and water hardness

5. Organic and Inorganic Matter: Organic matter in the form
of serum, blood, pus, or fecal or lubricant material can
interfere with the antimicrobial activity of disinfectants ,
organic material can protect microorganisms from attack by
acting as a physical barrier
6. Duration of Exposure
7. Biofilms :Microorganisms may be protected from
disinfectants by production of thick masses of cells and
extracellular materials, or biofilms . Biofilms are microbial
communities that are tightly attached to surfaces and cannot
be easily removed

CHEMICAL DISINFECTANTS
Alcohol
Chlorine and chlorine compounds
Formaldehyde
Glutaraldehyde
Hydrogen peroxide
Iodophors
Ortho-phthalaldehyde (OPA)
Peracetic acid
Peracetic acid and hydrogen peroxide
Phenolics
Quaternary ammonium compounds
MISCELLENIOUS INACTIVING AGENTS
Metals as microbicides
Ultraviolet radiation
Pasteurization

Sterilants and high-level disinfectants
1 FORMALDEHYDE
 Formaldehyde – primarily available as a water-based
solution called formalin, which contains 37% formaldehyde
by weight – is used as a high-level disinfectant and
sterilant.
 Formaldehyde exerts its bactericidal, tuberculocidal,
fungicidal, virucidal and sporicidal effects in the aqueous
state, as well as in combination with low-temperature
steam.
 "This extremely reactive chemical’s mechanism of action is
attributed to its interactive with protein, DNA and RNA in
vitro, resulting in the disruption of DNA synthesis.
 It can also penetrate bacterial spores.

2 GLUTARALDEHYDE
Glutaraldehyde is a saturated dialdehyde widely used as a
potent sterilant and high-level disinfectant.
Its broad spectrum, covering bactericidal, sporicidal,
fungicidal and virucidal activity, makes it an ideal chemical
for the low-temperature disinfection and sterilisation of
critical and semi-critical equipment such as endoscopes,
dialysers and surgical tools.
"Glutaraldehyde exposure should be monitored to ensure a
safe working environment."
Aqueous solutions of glutaraldehyde when activated
(rendered alkaline at 7.5- 8.5pH) its microbicidal action is
on the outer layers of bacterial cells and alter RNA, DNA
and protein synthesis within microorganisms.

Note.
Can be used for HLD (by soaking for 10-20
minutes) and sterilization (by soaking for 10-12
hours) of instruments and other items.
Leaves a residue, instruments and other items
must be rinsed thoroughly with boiled water
after HLD and with sterile water after
sterilization.
A new solution should be prepared every 14 days
(or sooner, if it becomes cloudy).
Preparations vary, follow the manufacturer’s
instructions.
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Disadvantages
. Acute or chronic exposure, resulting in
a)skin and mucous membrane irritation
b)multiple pulmonary symptoms such as
occupational asthma and allergic rhinitis
have been reported in healthcare workers

3 Ortho-phthalaldehyde
 Ortho-phthalaldehyde (OPA) has been accepted as a
better, safer alternative to glutaraldehyde in most
healthcare facilities.
Cidex OPA by Advanced Sterilization Products was cleared
by the as a high-level disinfectant and emerged as a
suitable replacement of glutaraldehyde for the disinfection
of endoscopes.
OPA has excellent microbiocidal activity and superior
mycobactericidal activity compared with glutaraldehyde,
and has potent bactericidal and sporicidal activity.
 Like glutaraldehyde, it interacts with amino acids, proteins
and microorganisms.

OPA has many advantages over glutaraldehyde, such as
improved stability at varying pH ranges,
 lower inhalation exposure risk and a wider range of
material compatibility,
although it costs almost three times more; but,
considering the cost of the sophisticated ventilation
systems needed to minimise the respiratory hazards of
using glutaraldehyde, OPA is more economical

4 HYDROGEN PEROXIDE
Disinfectant solutions containing 7.5% hydrogen
peroxide have been approved for sterilisation and high-
level disinfection in healthcare settings.
Its good, broad-spectrum bactericidal, virucidal,
sporicidal and fungicidal properties, combined with its
excellent stability and environmentally friendly
characteristics,
This have made hydrogen peroxide the disinfectant of
choice for semi-critical and non-critical equipment
while being an ideal surface disinfectant.
 Hydrogen peroxide produces destructive hydroxyl-free
radicals that act on membrane lipids, DNA and other
essential cell components.

5 Peracetic acid
Another emerging alternative to ethylene oxide and
aldehyde sterilants is peracetic acid.
 Per-acetic acidbased solutions are considered to be a
more potent disinfectant than hydrogen peroxide
They are sporicidal, bactericidal, virucidal and fungicidal
at low concentrations; and are environment friendly.
It also acts as an environmental surface sterilant, and
behaves similarly to other oxidising agents, disrupting cell
wall permeability.

6 Hydrogen peroxide/peracetic acid combination
Per-acetic acid, when combined with hydrogen peroxide,
was found to be more effective, typically against
glutaraldehyde-resistant mycobacteria.
The combination of per-acetic acid and hydrogen peroxide
has been used for disinfecting haemodialysers

INTERMEDIATE-LEVEL DISINFECTANTS
7. Sodium hypochlorite
 Chlorine-releasing agents (CRAs), the most popular sodium
hypochlorite solution, are widely used for the disinfection
of hard surfaces and blood spillages containing the human
immunodeficiency virus or hepatitis B virus.
 Recently, sodium hypochlorite was designated as the best
defence against hospital-acquired and community-acquired
Clostridium difficile infections.
 With a broad spectrum of antimicrobial activity, sodium
hypochlorite is inexpensive with low toxicity.

JIK DILUTION
Manufacturer concentration or
required concentration
i.e. (4-6/0.5)-1=9
 Available strength(4-6%)
Required strength(0.5%)
RATIO 1:9
i.e. One part of jik:9 parts of water

 Hypochlorites, the most widely used of the
chlorine disinfectants, are available as liquid (e.g.,
sodium hypochlorite) or solid (e.g., calcium
hypochlorite).
Advantages
.They have a broad spectrum of antimicrobial
activity
They do not leave toxic residues
 Are unaffected by water hardness
Are inexpensive and fast acting
Remove dried or fixed organisms and biofilms from
surfaces and have a low incidence of serious toxicity .

DISADVANTAGES
Sodium hypochlorite can
produce ocular irritation or oropharyngeal,
esophageal, and gastric burns hypochlorites
corrosiveness to metals in high concentrations
 inactivation by organic matter,
 discoloring or “bleaching” of fabrics,
release of toxic chlorine gas when mixed with
ammonia

Mode of Action.
The exact mechanism by which free chlorine destroys
microorganisms from a number of factors:
decreased uptake of nutrients
 inhibition of protein synthesis
 decreased oxygen uptake
 decreased adenosine triphosphate production
breaks in DNA
 and depressed DNA synthesis
 The actual microbicidal mechanism of chlorine
might involve a combination of all these factors

8 Iodophors
 Iodophors, complexes of iodine and a solubilising agent or
carrier, are used as antiseptics and surface disinfectants.
Iodine has bactericidal, fungicidal, tuberculocidal,
virucidal and sporicidal properties, while its antiseptic
properties are well known.
 Iodophors, such as povidone-iodine and poloxamer-iodine,
are much more stable, have fewer irritant characteristics
and exert better microbicidal action than aqueous iodine
solutions.
 The iodophors are still used in healthcare settings for
disinfecting blood culture bottles and medical equipment
such as thermometers.

Low-level disinfectants
9 Phenols
 "Phenolic disinfectants disrupt the cell membrane of
microorganisms."
 Since Dr Joseph Lister’s use of phenols for his pioneering
work on antiseptic surgery,
 phenolic disinfectants have been used as low and
intermediate-level disinfectants.
 Phenolic disinfectants are effective bactericides,
fungicides, tuberculocides and virucides, but are
ineffective against spore-forming bacteria such as
Clostridium difficile.

 phenolic disinfectants are used to disinfect surface areas
and non-critical medical devices.
 Phenolic disinfectants disrupt the cell membrane of
microorganisms, and two phenol derivatives used
commonly in hospital disinfectants are
orthophenylphenol (Amphyl, Reckitt Benckiser) and
ortho-benzyl-parachlorophenol (Clorox Disinfectant
Cleaner

10 Quaternary ammonium compounds
 Quaternary ammonium compounds (QACs) are used for
a variety of clinical purposes such as preoperative
disinfection,
 disinfection of non-critical instruments,
 and hard-surface cleaning and deodorisation.
 QACs possess bactericidal, fungicidal and virucidal
properties; however, they only display
mycobacteriostatic and sporostatic activity.
 Ruhof Enzymatic Instrument and Scope Cleaner
Endozime AW Plus Low Foam is a unique low-foaming
formulation of enzymes that remove blood, fat,
carbohydrates, starches and protein from all surgical
instruments and scopes in as little as 2 minutes.

11. ALCHOHOL
In the healthcare setting, “alcohol” refers to two
water-soluble chemical compounds—ethyl alcohol
and isopropyl alcohol—that have generally
underrated germicidal characteristics .
 These alcohols are rapidly bactericidal rather than
bacteriostatic against vegetative forms of bacteria;
they also are tuberculocidal, fungicidal, and virucidal
but do not destroy bacterial spores.
.

Mode of Action.
The most feasible explanation for the
antimicrobial action of alcohol is denaturation of
proteins.
This mechanism is supported by the observation
that absolute ethyl alcohol, a dehydrating agent,

Sterilization process has the following
steps
• Cleaning
• Packaging
• Loading
• Sterilizing
• Storage

1. CLEANING
Items must be cleaned using water with detergents or
enzymatic cleaners before processing.
Cleaning reduces the bio-burden and removes foreign
material (i.e., organic residue and inorganic salts) that
interferes with the sterilization process by acting as a
barrier to the sterilization agent
Surgical instruments are generally pre-soaked or pre-rinsed
to prevent drying of blood and tissue.
Precleaning in patient-care areas may be needed on items
that are heavily soiled with feces, sputum, blood, or other
material.

Items sent to central processing without removing gross
soil may be difficult to clean because of dried secretions
and excretions.
Cleaning and decontamination should be done as soon as
possible after items have been used
2. Packaging
 Once items are cleaned, dried, and inspected, those
requiring sterilization must be wrapped or placed in rigid
containers and should be arranged in instrument
trays/baskets according to the guidelines provided

These guidelines state that hinged instruments should be
opened; items with removable parts should be
disassembled unless the device manufacturer or
researchers provide specific instruction
devices with concave surfaces should be positioned to
facilitate drainage of water
heavy items should be positioned not to damage delicate
items
 the weight of the instrument set should be based on the
design and density of the instruments and the
distribution of metal mass

Wrapping should be done in such a manner to avoid
tenting and gapping. The sequential wrap uses two
sheets of the standard sterilization wrap, one wrapped
This latter method provides multiple layers of protection
of surgical instruments from contamination and saves
time since wrapping is done only once

3. LOADING
• All items to be sterilized should be arranged so all
surfaces will be directly exposed to the sterilizing agent.
• Thus, loading procedures must allow for free circulation
of steam around each item.
There are several important basic principles for loading a
sterilizer:
 allow for proper sterilant circulation
 perforated trays should be placed so the tray is
parallel to the shelf
 Non-perforated containers should be placed on their
edge (e.g., basins)
 small items should be loosely placed in wire baskets;
 and peel packs should be placed on edge in perforated
or mesh bottom racks or baskets

 Sterilization refers to any process that eliminates,
removes, kills, or deactivates all forms of life (in particular
referringto microorganisms suchas fungi, bacteria, viruses,
spores,
 Sterilization can be achieved through various means,
including heat, chemicals, high pressure, and filtration.
 Sterilization is distinct from disinfection, sanitization,
and pasteurization in that those methods reduces rather
than eliminate all forms of life and biological agents
present.

. 4.Storage
Sterile supplies should be stored far enough from
 the floor (8 to 10 inches),
 the ceiling (5 inches unless near a sprinkler head
 From the outside walls (2 inches) to allow for
adequate air circulation, ease of cleaning, and
compliance with local fire codes
 wrapped surgical trays remain sterile for varying
periods depending on the type of material used to
wrap the trays.

Safe storage times for sterile packs vary with the
wrapper and storage conditions (e.g., open versus closed
cabinets).
Supplies wrapped in double-thickness muslin comprising
four layers, remain sterile for at least 30 days.
Supplies wrapped in single-thickness muslin comprising
one or two layers, remain sterile for at least 14 days
Unwrapped Items
Should be used immediately after removal from the
autoclave.
They can also be kept in a covered, sterile container for
up to one week

Factors that determines the instruments to be considered
as unsterile:
 Sterile items that become wet are considered
contaminated because moisture brings with it
microorganisms from the air and surfaces.
 Closed or covered cabinets are ideal but open shelving
may be used for storage.
 Any package that has fallen or been dropped on the floor
must be inspected for damage to the packaging and
contents (if the items are breakable).
 If the package is heat-sealed in impervious plastic and the
seal is still intact, the package should be considered not
contaminated.
 Any item that has been sterilized should not be used after
the expiration date has been exceeded or if the sterilized
package is wet, torn, or punctured

1.STEAM STERILIZATION
 The basic principle of steam sterilization, as
accomplished in an autoclave, is to expose each
item to direct steam contact at the required
temperature and pressure for the specified time.
 Thus, there are four parameters of steam
sterilization:
 steam,
 pressure,
 temperature,
 and time.

 The ideal steam for sterilization is dry saturated
steam and entrained water (dryness fraction
≥97%).
 Pressure serves as a means to obtain the high
temperatures necessary to quickly kill
microorganisms.
 Specific temperatures must be obtained to ensure
the microbicidal activity.
 The two common steam-sterilizing temperatures
are 121°C (250°F) and 132°C (270°F).

 These temperatures must be maintained for a
minimal time to kill microorganisms.
 Recognized minimum exposure periods for
sterilization of wrapped healthcare supplies are
30 minutes at 121°C (250°F) in a gravity
displacement sterilizer or
 4 minutes at 132°C (270°F) in a prevacuum
sterilizer

At constant temperatures, sterilization times vary
depending on the type of item (e.g., metal versus
rubber, plastic, items with lumens), whether the
item is wrapped or unwrapped, and the sterilizer
type
Proper autoclave treatment will inactivate all
resistant bacterial spores in addition to fungi,
bacteria, and viruses, but is not expected to
eliminate all prions, which vary in their resistance.

The information is checked to ensure that the conditions
required for sterilization have been met:
 Indicator tape is often placed on the packages of products
prior to autoclaving, and some packaging incorporates
indicators.
 The indicator changes color when exposed to steam,
providing a visual confirmation.
 Bioindicators can also be used to independently confirm
autoclave performance.
 These indicators are placed in locations where it is difficult
for steam to reach to verify that steam is penetrating there.
 After sterilization, an object is referred to as being sterile
or aseptic

MODE OF ACTION
 Moist heat destroys microorganisms by the
irreversible coagulation and denaturation of
enzymes and structural proteins.
 In support of this fact, it has been found that the
presence of moisture significantly affects the
coagulation temperature of proteins and the
temperature at which microorganisms are
destroyed.

USES
 Steam sterilization should be used whenever
possible on all critical and semicritical items that
are heat and moisture resistant to prevent
pathogen transmission.
 Steam sterilizers also are used in healthcare
facilities to decontaminate microbiological waste
and sharps containers .

Steps of steam sterilization:
a) Decontaminate, clean and dry all instruments and
other items to be sterilized.
b) Open or unlock all joined instruments and other items,
for example, hemostats.
c) Disassemble scissors with sliding or multiple parts to
allow steam to reach all surfaces of the item. Do not
arrange the instruments and other items tightly together,
because steam will not reach all surfaces.
d) Wrap instruments and other items in two layers of
paper, cotton or muslin fabric before steam sterilization.
e) If you are using a drum, make sure the holes are open.
MUTHEE.M
76

f) Arrange all packs, drums or unwrapped items in
the chamber of the autoclave in a way that allows
steam to circulate freely.
g) Always follow the manufacturer’s instructions on
how to operate the autoclave but sterilize wrapped
items for 30 minutes and unwrapped items for 20
minutes at 121º C and 15.36 Pascal pressure.
h) If the autoclave is automatic, the heat will shut
off and the pressure will begin to fall once the
sterilization cycle is complete.
i) If the autoclave is not automatic, turn off the heat
or remove the autoclave from the heat source after
30 minutes if items are wrapped, or after 20
minutes if items are unwrapped..
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Wait until the pressure gauge reads “zero” to
open the autoclave
Open the lid or door to allow the remaining
steam to escape. Leave instrument packs or items
in the autoclave until they dry completely.
Remove the packs, drums or unwrapped items
from the autoclave using sterile pick ups.
Place packs or drums on a surface padded with
paper or fabric until they are cool to prevent
condensation.
Wait until the packs, drums or items reach room
temperature before storing.
MUTHEE.M
78

Storage time and handling of sterile packs
should be kept to a minimum, since the
likelihood of handling and contamination
increases over time.
Place sterile packs in closed cabinets in areas
that are not heavily trafficked, have moderate
temperature and are dry.
.
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79

2. FLASH STERILIZATION
 Flash sterilization is a modification of conventional steam
sterilization in which the flashed item is placed in an
open tray or is placed in a specially designed, covered,
rigid container to allow for rapid penetration of steam.
 It is not recommended as a routine sterilization method
because of :-
 lack of timely biological indicators to monitor
performance
 absence of protective packaging following
sterilization possibility for contamination of
processed items during transportation to the
operating rooms,
 the sterilization cycle parameters (i.e., time,
temperature, pressure) are minimal.

TO ADDRESS SOME OF THESE CONCERNS, MANY HEALTHCARE FACILITIES HAVE
DONE THE FOLLOWING:
placed equipment for flash sterilization in close proximity
to operating rooms to facilitate aseptic delivery to the
point of use
 use biological indicators that provide results in 1 hour
for flash-sterilized items
 used protective packaging that permits steam
penetration.
 reusable sterilization container systems have been
designed and validated by the container manufacturer
for use with flash cycles.
 NOTE :When sterile items are open to air, they will
eventually become contaminated. Thus, the longer a
sterile item is exposed to air, the greater the number of
microorganisms that will settle on it.

Uses
 Flash sterilization is considered acceptable for
processing cleaned patient-care items that cannot be
packaged, sterilized, and stored before use.
 It also is used when there is insufficient time to
sterilize an item by the preferred package method.
 Flash sterilization should not be used for reasons of
convenience as:
 an alternative to purchasing additional instrument
sets, or to save time because of the potential for
serious infections,
 not recommended for implantable devices
however, flash sterilization may be unavoidable for
some devices (e.g., orthopedic screw, plates).

3.ETHYLYNE OXIDE
ETO is a colorless gas that is flammable and explosive.
 The four essential parameters that influence the
effectiveness of ETO sterilization are:-
 gas concentration (450 to 1200 mg/l)
 temperature (37 to 63°C)
 relative humidity (40 to 80%)(water molecules carry
ETO to reactive sites)
 and exposure time (1 to 6 hours).

Advantage
it can sterilize heat- or moisture-sensitive medical
equipment without deleterious effects on the material
used in the medical devices .
Disadvantages
 irritation to skin, eyes, gastrointestinal or respiratory
tracts
 central nervous system depression.
 Chronic inhalation has been linked to the formation of
cataracts
 cognitive impairment, neurologic dysfunction
 increased risk of spontaneous abortions and various
cancers
 For this reason, following sterilization the item must
undergo aeration to remove residual ETO.

Mode of Action
 The microbicidal activity of ETO is considered to be
the result of alkylation of protein, DNA, and RNA.
Alkylation, or the replacement of a hydrogen atom
with an alkyl group, within cells prevents normal
cellular metabolism and replication.
Uses
 ETO is used in healthcare facilities to sterilize critical
items (and sometimes semi-critical items) that are
moisture or heat sensitive and cannot be sterilized by
steam sterilization.

4.PER-ACETIC ACID
 Per acetic acid is a highly biocidal oxidizer that maintains
its efficacy in the presence of organic soil.
 It removes surface contaminants on endoscopic tubing.
 An automated machine using peracetic acid is used to
sterilize medical, surgical, and dental instruments
chemically
 The sterilant, 35% peracetic acid, and an anticorrosive
agent are supplied in a single-dose container.
 The container is punctured at the time of use,
immediately prior to closing the lid and initiating the
cycle.
 The concentrated peracetic acid is diluted to 0.2% with
filtered water (0.2 mm) at a temperature of
approximately 50°C.

 The diluted per-acetic acid is circulated within the
chamber of the machine and pumped through the
channels of the endoscope for 12 minutes,
decontaminating exterior surfaces, lumens, and
accessories.
 The per-acetic acid is discarded via the sewer and the
instrument rinsed four times with filtered water.
Mode of Action
 it denatures proteins, disrupts cell wall permeability, and
oxidizes sulfhydral and sulfur bonds in proteins, enzymes,
and other metabolites
Uses
 This automated machine is used to chemically sterilize
medical (e.g., GI endoscopes) and surgical (e.g.,
flexible endoscopes) instruments.

2. Dry Heat Sterilization or Hot-Air Oven (Electric Oven)
 This is the method of sterilization that requires heat for
a specific period of time.
 This method is used for sterilizing glass or metal
objects because high temperatures are necessary.
 Also used to sterilize instruments with cutting edges
 Need to ensure that the designated temperature is
reached
 170ºC – 1 hour
 160ºC – 2 hours
 150ºC – 2½ hours
 140ºC – 3 hours
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3. Chemical Sterilization
 This is the method of sterilization used for instruments
and other items that are heat sensitive or when heat
sterilization is unavailable.
 Instruments and other items can be sterilized by
soaking them in a chemical solutions such as
glutaraldehyde (cidex) or formalin, followed by rinsing
in sterile water.
 Glutaraldehyde is irritating to the skin, eyes and
respiratory tract. Wear gloves and limit your exposure
time. Keep the area well ventilated when using it.
Always follow manufacturer’s instructions before use.
 7% Glutaraldehyde : 8 – 10 hours, while 8% Formalin:
24 hours
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5. High Level Disinfection
This is the process that eliminates all micro-
organisms (including bacteria, viruses, fungi
and parasites), but does not reliably kill all
bacterial endospores which cause tetanus and
gas gangrene.
Is suitable for instruments and other items
that will come into contact with unbroken skin
or intact mucous membranes.
HLD can be performed by boiling (20minutes),
use of chemicals (20minutes in 3% formalin/
2% glutaraldehyde) or steaming.
MUTHEE.M
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STERILIZATION AND DISINFECTION OF SURGICAL INSTRUMENTS.pptx

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