Download sterilization

Surgical Preparation
Lobna El Fiky
Assistant Professor of
ORL, H&N surgery
Ain Shams University
Historical perspectives
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Antiseptic = Greek for “against putrefaction”
Accidental observation of certain substances
stopped putrefaction of meat…
Mercuric Chloride: Arabian physicians in
Middle Ages
Tincture of iodine: 1839
Pasteur’s publication: 1863: microbial origin
of putrefaction
Historical perspectives
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As often in history of medicine: Change of
practice depended on the persistence of
John Lister 1870,
He introduced vigorous application of phenol
in surgery, for dressing wounds, for
sterilization of instruments
Sterilization
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It is the process that destroys all microorganisms
(including bacterial microspores).
The skin could never be sterilized without its own
destruction.
Disinfection
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A process which destroys only the vegetative
forms of organisms =basically clean.
A disinfectant (germicide, antiseptic): any
chemical substance with either a bactericidal or
a bacteriostatic action.
Antiseptic -- Agent applied to living tissue
Disinfectant -- Agent applied to inanimate
surface
Surgical Disinfection
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This is an essential part of a programme for
the control of infection.
High Risk Items: as they come in close
contact with broken skin or those that breach
mucous membranes or are introduced into a
sterile cavity.
Requirements for decontamination
practice
The basic requirements for good decontamination
practice are:
 A Management control system;
 Appropriate facilities;
 Appropriate equipment;
 Properly trained and supervised staff;
 Ensuring that single use medical devices are not
reused;
 Records of decontamination are kept.
Methods of Disinfection
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Physical: The most important as they can be relied on to
ensure the sterilization of articles used in the treatment
of patients:
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Chemical: Less effective, used for personnel
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Thermal: Heat or Steam
Radiation: infra-red radiation, - rays,  particles
Filtration:utilizing filters capable of screening out microorganisms
Organic
Inorganic
Gaseous disinfectants: very efficient, not routine
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Formaldehyde gas
Ethylene oxide
MANUAL CLEANING
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Cleaning is vital prior to any decontamination
procedure.
‘Detergent’ removes the nutritive material on
which bacterial survival and multiplication
may take place.
This reduces the number to a level which is
not harmful for health.
MANUAL CLEANING
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Effective cleaning to remove protein from
medical devices is paramount (agents such as
CJD are not inactivated by heat).
Dismantle or Open the instrument to be cleaned
Friction for 2-3 minutes
Brush, Wipe, Agitate, Irrigate, jet wash or hand
spray the item to dislodge and remove all visible
soil
Rinse the item thoroughly with clean water
Drying
Physical Methods of Disinfection
HEAT
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DRY HEAT
Kills by Destructive oxidation of cell constituents
Surest incineration
Hot-air oven:
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inefficient, poor conductor of heat, penetrates feebly.
160°C for 1 hour: damages fabrics, melts rubber
Used for: Glassware, oily fluids, powders
Physical Methods of Disinfection
HEAT
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MOIST HEAT
Effective at low temperature, in a shorter period
of time
Boiling: 100°C for 30 minutes
Pasteurisation: 63°C for 30 minutes
Tyndallisation: steaming for 20 minutes for 3
successive days
Steaming under pressure= Autoclaving
Advantages of steam
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Kills by denaturing & coagulating enzymes &
proteins
More rapid (maximum needed time 45mn) & at
lower temperature
Condensation of steam leads to liberation of
latent heat which raises the temperature, and
gives more penetration
Half dense as air, so has better penetration
Steam Sterilization: Autoclave
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Principle: An autoclave is a self locking
machine that sterilizes with the high
temperature that steam under pressure
can reach.
High-vacuum pumps remove as much as
possible air before the steam is admitted,
so the required temperature is reached
very rapidly.
Steam criteria
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Dry: no suspended droplets of water
Close to its point of condensation: not
superheated
Free from air: as it decreases the temperature
and the penetration
Temperature
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121°C: 15mn-30mn
134°C: 4-7mn Flashing
Steps of autoclaving
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Water in the surrounding container full and heated
Articles in cabinet, doors bolted
Vacuum to evacuate as much air as possible
Steam is admitted at a high pressure of and when the
thermometre reaches the required temperature,
sterilisation begins
Sterilisation is continued for the required time and then
the steam is turned off.
Drying is carried-out by reapplying a vacuum to evacuate
the steam, introducing dry filtered air into the cabinet (for
15 minutes).
Efficient Autoclaving
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All instruments must be double
wrapped in linen or special paper or
placed in a special metal box
equipped with a filter before
sterilization.
The white stripes on the tape change
to black when the appropriate
conditions (temperature) have been
met.
Expiration dates should be printed on
all equipment packs.
There should be a uniform
development of bars throughout the
length of the strips.
Ready made plastic bags with strips
printed with a sensitive ink.
Control of autoclave efficiency
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Bowie-Dick test: Used for high-vacuum autoclaves, Done
every day:
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In the middle of a test pack of towel, a paper on to which a strip of
a specific tape is put, for testing.
Uniform development of dark color indicates that the steam has
passed freely and rapidly to the center of the load.
Biological sterilization indicators: Spores of a nonpathogenic organism: Done weekly
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They are killed at 121°C after 15 minutes.
Attempts to culture them is subsequently made
RADIATION DISINFECTION
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High energy ionizing radiation destroys
microorganisms and is used to sterilize
prepacked, Single-use, surgical equipment
by manufacturers
Common sources of radiation include
electron beam and Cobalt-60
CHEMICAL DISINFECTION
A SATISFACTORY AGENT SHOULD:
 Be active against a wide range of organisms and
spores. Only few are truly sterilizer
 Have a rapid action
 Should not be toxic or irritant to the skin
 Should be Persistent
There is no one disinfectant which can be
used to kill all micro-organisms in all
situations.
Types of Chemical disinfectants
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Inorganic:
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Iodine
Chlorine
Organic:
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Alcohols
Aldehydes
Phenols
Cationic surface-active agents
Inorganic disinfectants
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The halogens: Chlorine and Iodine
Have a rapid action against vegetative
organisms and spores= true sterilizers
Their action is annulled by foreign organic
material
Iodine disinfectants
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The broadest spectrum of all topical anti-infectives, with action
against bacteria, fungi, viruses, spores, protozoa, and yeasts.
Tincture iodine:
– 2.5% iodine & 2.5% potassium iodide in 90% ethanol.
– Best skin disinfectant
– Irritating to raw surfaces: due to its alcoholic component
– Allergic dermatitis
Iodophors: Solutions of iodine in non-ionic detergents= Povidone
iodine= Betadine
– Less irritating and less staining
– Less disinfectant than tincture
Chlorine disinfectants
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Powerful, Disinfect water
Particularly active against viruses
Concentrated solutions too corrosive
Usually diluted with a compatible detergent
Organic Disinfectants
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Alcohols: bactericidal: 50-70% ethanol
Aldehydes:
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Phenols: continued activity in organic matter as human
excreta.
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Formalin: irritant, powerful=sterilizer
Glutaraldehyde: less irritant, not volatile, more rapid action.
Phenol: Toxic, expensive
Cresols: Lysol
Chloroxylenol: Dettol
Chlorhexidine: Hibitane- Alkanol
Hexachlorophane
Cationic surface-active agents:
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Cetrimide: Cetavlon
Alcohol
Isopropyl Alcohol 70% (or Ethyl Alcohol 90%)
ADVANTAGES:
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Causes protein denaturation, cell lysis, and metabolic
interruption.
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Degreases the skin.
DISADVANTAGES:
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Ineffective against bacterial spores and poorly effective
against viruses and fungi.
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Glutaraldehyde (Cidex)
Cold Sterilization:
 Instruments must be dry before immersion.
 Glutaraldehyde is bactericidal, fungicidal,
viricidal, and sporicidal
 Sterilization: a 10 hour immersion. This
prolonged chemical action can be more
detrimental to surgical instruments.
 3 hours exposure time is needed to destroy
spores.
 If the instruments need to be "disinfected"
only, cold sterilization is okay as
disinfection will take place in only 10
minutes.
Lysoformin
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Formaldehyde & glutaral
Lysoformin: liquid concentrate with which any dilution
required can be made by simply adding water (20ml + 48L)
The timing depends on the concentration used:
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flexible endoscopes
deactivation of HBV & HIV
1.5 % - 30 min
2.0 % - 15 min
Used for heat labile instruments and cleaning
Does not harm metal instruments
Chlorhexidine Gluconate
Hibitane vs Alkanol
Broadest spectrum
Better residual activity than iodophors
Occasional skin sensitivity
ADVANTAGES:
Rapid action
Residual activity is enhanced by repeated use
Less susceptible to organic inactivation than povidone iodine
DISADVANTAGES:
Occasional skin sensitivity.
Inactive against bacterial spores
Activity against viruses and fungi is variable and inconsistent
May harm metal instruments
Gaseous Disinfection
Ethylene Oxide Sterilization: EO Gas
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Colorless gas, available as cartridges
Toxic and flammable, Odor similar to
ether
Has an extremely well penetration, even
through plastics
Microorganism destruction is caused by a
chemical reaction
Effective sterilization is dependent on
concentration of gas, exposure time,
temperature, and relative humidity
Powerful sterilizer: Kills all known
viruses, bacteria (including spores), and
fungi
EO Gas Sterilizer
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Is used in large hospitals, as it is expensive,
dangerous, needs more expertise.
Used for heat sensitive instruments: fabrics,
plastics, suture material, lenses, endoscopes,
electrical equipment and finely sharpened
instruments.
At 20°C-25°C: sterilization takes 18hours
At 50°C-60°C: sterilization takes 4 hours
In Demerdash: The average of the cycle is 8-14
hours
Sterility Check List
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Before assuming a pack is sterile, always
evaluate the following before opening the
pack:
Expiration date
Indicator color change
General condition of wrapper and how it
had been stored
Always check for holes or moisture damage
Standards for
Surgical Scrubbing, Gowning and
Gloving
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The pre-surgical practice of scrubbing,
gowning and gloving is integral to the
minimization of risk of infection from microorganisms present in the wound at the time
of surgery.
Accessing to the operating theatre
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Wear prescribed
operating suite attire
Remove jewellery
Keep fingernails short,
clean, healthy
Wear appropriate
protective attire: masks,
head, overshoes..
REMEMBER
What went inside the machines is
the STERILISED material
 Personnel are only DISINFECTED
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Surgical Hand scrub
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No touch: infrared robinets, with your elbow, leg…
Use brush??
The ideal duration of the scrub is not agreed.
Accepted time is 5 minutes: appears safe
Some surgeons do not rinse off the chlorhexidine or
Betadine in order to enhance residual activity.
Alternative: Two-stage surgical scrub:
– an initial 1- or 2-minutes scrub with 4% chlorhexidine
gluconate or povidone-iodine followed by application
of an alcohol-based product
Surgical Hand scrub
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Trim fingernails and Wash for 30-60 seconds
with surgical scrub.
Scrub fingers with a sterile scrub brush
Make sure to scrub all sides of each finger,
including the area between fingers.
Surgical Hand scrub
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Scrub hands and arms with a sterile scrub brush. Make
sure to scrub each surface of each hand and arm
An accepted contact time is 10 brush strokes per surface
During scrubbing, rinsing and drying, hands are held
above elbows. This is done so that water will not be
dripping from upper arms onto lower arms and hands
Drying Hands
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A sterile towel is included within the sterile gown pack.
One hand and forearm are dried by one side of the towel.
Always dry in the direction of hand to elbow so that
contamination of the upper arm is not spread by the towel
to the surgeon's hand.
Gowning
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All gowns are folded and packaged for sterilization, with
the inside exposed so that the surgeon may handle the
gown without contaminating the outside of the gown.
Grasp the exposed inside of the gown and lift the gown
away from the table.
Your hands are disinfected and the gown is sterilized
Gowning
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Unfold the gown by placing hands into the white arm
holes. Continue placing hands and arms through the
sleeves..
Gowning
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An assistant fastens the neck tie and the
inside waist tie.
PLEASE: DO NOT DRY YOUR HANDS IN
THE FRONT OF THE GOWN
Types of Gowns
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Disposable Paper Gown: resistant to wetting so they
are less permeable to bacteria, expensive. It is usually a
wrap around gown. The ties "wrap around" the surgeon.
Linen (cloth): comfortable and reusable. When it
becomes wet, bacteria can permeate. The cloth gown is
also known as a front sterile gown. The gown is just tied
in the back.
Gloving
Sterile surgical gloves can be worn by:
Open method:
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The gloves are presented to enable the introduction of the
hands on the inside surface directly
The nurse with her sterile glove opens the glove for the
surgeon who introduces directly his hands on the inside surface
of the glove
DO NOT ADJUST THE FIRST
GLOVE BEFORE PUTTING
THE SECOND ONE !!!
Gloving
Closed gloving:
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This is the introduction of hands covered with the
cuff of a sterile gown.
So, If you are planning on closed gloving, do not
thrust hands through the cuffs.
This is usually performed by the first person to
be sterilized= the nurse
Gloving: Closed method
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An assistant opens the sterile pack of gloves and drops
them into the sterile field.
The inside of the cuff of the glove is grasped by the
opposite hand (still within the gown) until introduction
Patient Preparation
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Sterilization is best done with a detergent
followed by a disinfectant on a larger area of the
surgical field. H&N??
Use Ample Detergent
Scrub roughly the skin in any direction for 2-3mn
??Remove the excess of the detergent
Apply the disinfectant first on the most clean area
Scrub in one direction only
Draping
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Standard head drape: two towels, one under
the shoulders and the other wrapped around
the head
Better to suture the drapes to the skin to
prevent shifting
Towels are used for lateral draping
Drapes should lie flat
Practical Sterilization
Instruments sterilization
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Metal Instruments: Avoid chemical sterilization
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Autoclave
EO chamber
Formaldehyde beads or powder
Sharp-edged: avoid heating & wetting:
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EO chamber
Formaldehyde beads or powder
Practical Sterilization
Instruments sterilization
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Catheters, gloves,…: depend on pre-sterilized,
disposable equipment
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Endoscopes: avoid heat
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Radiation
EO chamber
Cidex
Lysoformin
Autoclaving
Handles of drills:
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Autoclave after washing and oiling
EO chamber
THANK YOU