THE PRESENTATION INCLUDES STERILIZATION AND DISINFECTION TECHNIQUES WITH DESCRIPTION OF CENTRAL STERILE SUPPLY DEPARTMENT (CSSD) .

1. CHANCHAL BHARDWAJ
B.Sc. Nursing

2.  An article, surface, or medium is freed from
all living form either in the vegetative or
spore state.
 In practice it, kills more than 106 organisms
including spores of a defined, exceptionally
high degree of resistance.

3. 1) Physical agents
 Heat
 Radiation
 Filtration
2) Chemical agents

4.  Culture media-should not be contaminated
with environmental organism and
environment should not be contaminated
with cultured organism to cause infection.
 All material that are used or exposed to
microorganism should be sterilized before
use, reuse or disposal.

5. 1) High temperature/ pressure sterilization
a) Dry heat
 Red heat
 Flaming
 Hot air oven
b) Moist heat
 Free steaming
 Autoclaving

6. 2) Filtration
 Cellulose membrane filter
 Syringe filters
 High- Efficiency Particle Arresters (HEPA
filters)
3) Radiation
 Ultra violet radiation
4) Chemical Sterilients
 Formaldehyde, Glutaraldehyde,
Orthopthaldehyde

7. 1. Nature of heat.
2. Temperature and time.
3. Number of microorganisms present.
4. Characteristics of the organisms.
5. Nature of the article to be sterilized.

8.  Principle –
1. Protein denaturation.
2. Oxidative damage.
3. Toxic effects of elevated levels of
electrolytes.

9.  Wire loops are
sterilized by heating to
'red hot' in bunsen
burner or spirit lamp
flame.
 Temperature is above
100°C.
 Use- for isolation of
colonies from culture
or further processing.

10.  Article is passed through the Bunsen flames
without allowing it to become red hot.
 Use sterilization of mouth of culture tubes,
cotton stoppers, glass slide and cover slips.
 Limitation- glass slide and other article
placed in cold surface after heating it may
crack.

11. Flaming

12.  Loads that can tolerate high temperature but
cannot be penetrated by steam or exposed
to moisture.
Temperature Time in minute
160oC 120
1700C 60
180oC 30

13.  Use- sterilization of by hot air oven
1. Glassware.
2. Metal instruments.
3. Oils and greases in sealed container.
4. Non aqueous materials, powders.
5. Aluminum tubes, tins or foils.
6. Wrappings of kraft paper.
7. Stoppers of cotton wool.

14.  Procedure
1. Oven is heated by electricity.
2. A fan to provide air circulation throughout
chamber.
3. Free circulation of air in between the object
4. Temperature indicator, control thermostat
and a timer.
5. Open mesh shelving adequate wall
insulation.

16.  Precaution –
1. Should not be overloaded.
2. Glass wear should be dry.
3. Test tube and flask should be wrapped in
paper and plugged with cotton.
 Limitation-
1. Opened only after the temperature is cooled
to 80oC.
2. Hot air is bad conductor of heat.
3. Penetration power is low.

17.  Safety features include
1. Temperature cut off at or above 200oC.
2. Door interlock.
3. Reset to zero when electricity is interrupted.
4. Hold time start only after all parts of load
have reached sterilization temperature.

18.  Sterilization control
1. Physical -temperature chart during each run.
2. Chemical - Browne ‘s tubes No 3.
3. Biological- 106 spores of non toxic stains of
Clostridium tetani or, Bacillus
subtilssubspniger are impregnated into
paper strip are used.

19.  Principle –Denaturation and Coagulation of
protein

20.  Pure steam in equilibrium with boiling water at
normal atmosphere pressure and temperature at
100oC for 5 min.
 Uses -to sterilize selective heat labile culture
media in laboratory DCA, XLD, TCBS, selenite F.
Non selective heat labile nutrient media.
 Disadvantage- prions (spongiform
encephalopathies) and spores of most resistant
thermophilic and mesophilic bacteria are
resistant to steaming.

21.  Koch and Arnold
Streamer
 Is upright metal
tank .
 Removable lid.
 Chimney .
 Water in the
bottom of tank is
heated.
 Containers of
media is laid on a
perforated shelf.
 Allow to cool to
80oC before
removing.

22.  Principle of autoclave- Water boils when
vapour pressure equals the surrounding
atmosphere.
 Water boils in a closed vessel so the pressure
is increased and temperature at which it boils
and converted to steam is above 100oC.
 So more energy is put into system as latent
heat & sensible heat.

23.  When steam comes in contact with surface-
1. Gives up latent heat and condense to water.
2. Reduction in volume sucks more steam to area.
3. This continues till temperature of surface is raised to
that of steam.
4. Moist condition for killing of microbe is ensure by
condensed water.
Temperature, pressure and time required in autoclaves
Temperature
(oC)
Pressure above
atmospheric
(psi)
Hold time (min)
121 15 lbs 15
126 20 lbs 10
133 30 lbs 3

24.  Sterilization hold time-time for which load
should be exposed to pure dry, saturated
steam at effective temperature to ensure
sterilization.
 When sterilization holding time is achieved;
the heater is turned off and autoclave is
allowed to cool, till the pressure gauge inside
is equal to atmosphere pressure.
 Exposure to temperature, pressure and time
depends on item.

26.  Uses
1. Unwrapped, non porous metallic items.
2. Packed & wrapped goods, linen textiles.
3. Discard load, nutrient media.
4. Porous load with containment level 3.
5. High risk microorganism of categories 3
and 4.

27.  Sterilization control
1. Physical temperature and pressure
monitoring gauge and thermocouple.
2. Chemical Browne’s tube, Bowie Dick tapes.
3. Biological paper strip of 106 spores of
Bacillus stearothermophillus are inserted at
different parts of load.

28. Chemical indicator Biological indicator

29.  Precaution
1. The method of air removal should be
efficient.
2. Steam should not be superheated or wet.
3. Sterilization of fluid sealed container-door
should not be opened until the temperature
of glass container has fallen below 80oC.
 Limitation materials undergo corrosion and
combustible lubricants cannot be used.

30. Cellulose membrane filter
 Use - sterilization of culture media and
other solution.
 Diameter of 13 to 293mm diameter and
pore size from 0.015 to 0.12µm.
 Two type of – capillary pore membrane-
filtration of viruses.
Labyrinthine pore membrane – filtration of
bacteria and yeast from solution.

31.  Limitation – cell growth is affected by soluble
wetting agent in some filters. This is
minimized by flushing the filter with glass of
distilled water or discarding first 5-10% of
filtrate.
 Sterilized by autoclaving.

32. Syringe filter
 Use – sterilization of heat labile sugars into
already sterilized media.
 Membrane of 13-25mm in diameter.
 Syringe fitted enables continuous or serial
flow of system.
 Limitation – only small volume can be used.

34. High-Efficiency Particle Arresters (HEPA filters)
 Large volume of air is freed from infection by
passage through HEPA filters.
 Use- air withdrawn from exhaust ventilated in
biological safety cabinet . And to decontaminate
air used in laminar air flow cabinet.
 HEPA filter should have the efficiency of 99.997%
when tested with dioctylophthalate or sodium
chloride smoke.

36. Ultraviolet radiation
 Mercury vapour lamps emit most of the
radiation in the region of 250-260nm.
 It is Bactericidal & used in biological safety
cabinet.
 Cabinet is exposed to radiation 20 min before
and after the use.

37.  Limitation – energy is
low so it has lesser
penetration power.
Lamps has limited life
span.
 Disadvantage-
photokeratitis, skin
burn or cancer.
 So it should be
shielded directly
falling from skin or
eyes.

38. Formaldehyde
 It’s a sterilant in both its liquid and gaseous
states.
 Bactericide, tuberculocide, fungicide,
virucide and sporicide.
 Principle Alkylating the amino and
sulfhydral groups of proteins and ring
nitrogen atoms of purine bases.

39. Formalin
 to kill bacterial cultures, clean contaminated surfaces and to
preserve anatomical specimens
Formaldehyde
 Fumigation of operation theatres, rooms, incubators and
safety cabinets
 To prepare viral vaccines
 As an embalming agent
 Aqueous formaldehyde solutions (1%–2%) have been used to
disinfect the internal fluid pathways of dialysis machines

40. Disadvantages
Health-care uses of formaldehyde are limited by its
 Irritating fumes and its pungent odor even at very
low levels (<1 ppm)
 Role as a suspected human carcinogen linked to
nasal cancer and lung cancer

41.  A saturated dialdehyde that has gained wide acceptance
as a high-level disinfectant and chemical sterilant
 >2% aqueous solutions of glutaraldehyde, buffered to pH
7.5–8.5 with sodium bicarbonate
Uses:
 For heat sensitive equipment like cystoscopes,
bronchoscopes, masks, endotracheal tubes

42. Advantages:
 Non corrosive
 Active in the presence of organic matter
Disadvantages:
 Irritant to eyes, skin, respiratory mucosa
 Potential Carcinogen

43.  Action similar to glutaraldehyde but has several
advantages over glutaraldehyde
 More stable
 Non Irritant
 More Mycobactericidal
 Low vapourizing activity and
 Does not require activation
DISADVANTAGE: Stains skin

44.  Use - Decontamination of laminar flow
biologic safety cabinets and sterilization of
incubator.
 Production of formaldehyde vapour.
1. By spraying equal volume of formaldehyde
and ethanol.
2. Boiling of formalin diluted with water to
have adequate atmosphere humidity.
3. Paraformaldehyde, a solid polymer of
formaldehyde, it can be vaporized by heat.

45.  Sterilization of incubator-
1. 150gm of KMNO4 to 280ml of formalin in a
petri dish or volumetric flask for every 1500
cuft (28.3cu.m).
2. Incubator is sealed for 24hrs.
3. 280ml of Ammonium solution is placed in
volumetric flask and again sealed for 24hrs.
4. Sterile media is incubated overnight to find
the efficacy of sterilization.

46.  Disadvantage –
1. Higher concentration at higher temperature
is explosive (than 2mg per liter of air at 20o
C.)
2. Paraformaldehyde which left after
sterilization is irritant vapour.
3. Suspected to cause nasal cancer and lung
cancer.
 Precaution –should use ammonia to
neutralize the formaldehyde that is remaining
after sterilization.

47.  Most of the media are sterilized by moist
heat. Membrane filters are used for those
media which are spoiled by heat.
 Autoclave is used for wrapped, unwrapped,
porous, non-porous loads, discard loads and
nutrient media.
 Materials that are exposed to high risk
organism are sterilized by high security
autoclave.

48.  Air that is contaminated by infectious
material is passed through the HEPA filter.
 Formaldehyde and UV radiation is used to
sterilize the BSC and laminar air flow.
 Incubator is sterilized by formaldehyde.
 Sterility of article should be maintained until
it is used.

50. Mode of Action: Denaturation of proteins
 Optimum bactericidal concentration is 60%–90% solutions
in water.Bactericidal, tuberculocidal, fungicidal and
virucidal but do not destroy bacterial spores.
 Ethyl Alcohol: (70%) Used as skin disinfectant
 Isopropyl Alcohol: more active than ethanol as it is a
better fat solvent, more bactericidal and less volatile,
used for clinical thermometers.Methyl Alcohol: Effective
against fungal spores and used for treating cabinets and
incubators

51. Disadvantages
 Alcohols are flammable
 Must be stored in a cool, well-ventilated area
 Evaporate rapidly, making extended exposure time
difficult to achieve unless the items are immersed
 Lack sporicidal action
 Cannot penetrate protein-rich materials

52. Mode of action: alkylation of amino, sulphydryl groups
in the protein molecule
1. Formaldehyde: 38% aqueous solution (formalin) and
Gas
2. Glutaraldehyde: 2% soln (Cidex)
3. Ortho-phthaldehyde (0.55%) solution
Antimicrobial spectrum: Bactericidal, fungicidal & virucidal

53.  Chlorine and Chlorine Compounds
 Iodophors

54. Mode of action: Multiple effects
 Oxidation of sulfhydryl enzymes and amino acids
 Loss of intracellular contents
 Decreased uptake of nutrients
 Inhibition of protein synthesis
 Breaks in DNA and depressed DNA synthesis
Antimicrobial spectrum: Destroy vegetative bacteria
and fungi but not spores

55. CHLORINE
Most commonly available disinfectant
Preparations: available in 3 forms
 Chlorine gas
 Sodium hypochlorite
 Calcium hypochlorite
Hypochlorites, the most widely used of the chlorine
disinfectants are available as liquid (sodium
hypochlorite) or solid (calcium hypochlorite)

56. USES
 Disinfection of water supplies, swimming pool
 Inorganic chlorine solution for spot-disinfection of
countertops and floors
 A 1:10–1:100 dilution of 5.25%–6.15% sodium
hypochlorite is recommended for decontaminating
blood spills
 Treatment with 0.5% sodium hypochlorite for 2hrs
destroys prions
 Water distribution system in hemodialysis centers and

57. Advantages:
 Broad spectrum of antimicrobial activity, do not leave toxic
residues, unaffected by water hardness, inexpensive and fast
acting
 Remove dried or fixed organisms and biofilms from surfaces
Disadvantages:
 Sodium hypochlorite as household bleach (5.25-6.15%) can
produce ocular irritation or oropharyngeal, esophageal, and
gastric burns
 Corrosiveness to metals
 Inactivation by organic matter
 Discoloring or “bleaching” of fabrics

58. Mode of Action Disruption of protein and nucleic acid
structure and synthesis
 Tincture of iodine: Iodine (2%) in a water-ethanol
solution of potassium iodide
 Iodophor: a combination of iodine and a solubilizing
agent or carrier that releases small amounts of free
iodine in aqueous solution. Eg povidone-iodine
 Germicidal efficacy of iodine but unlike iodine
nonstaining and relatively free of toxicity and irritancy

59. Antimicrobial spectrum:
Iodophors are bactericidal, mycobactericidal, and
virucidal but may require prolonged contact times to kill
certain fungi and bacterial spores
Uses:
 As antiseptics
 Iodophors have been used for disinfecting blood
culture bottles and medical equipment such as
thermometers and endoscopes

60. Widely used as wetting agents, Detergents and
Emulsifiers
• Cationic : Eg. Quaternary ammonium compounds.
• Anionic : Eg. Soaps
• Non ionic : Eg. Tween 80 and Triton x-800.
• Amphoteric surfactants: possess detergent properties
of anionic compounds and antimicrobial activity of
cationic compound eg. Tego compounds

61. Mode of action: Act by denaturing proteins and disruption
of cell membranes.
Advantages:
Have tuberculocidal activity and some are active in the
presence of organic matter
Uses:
 Common disinfectant used in laboratories and hospitals
Eg. Cresols, xylinol, Lysol
 Antiseptics
Eg. Chlorhexidine(savlon), chloroxylenol (Dettol),
hexachlorophene.

62. Disadvantages
Toxic and irritant to skin and hence they are only
used as disinfectants and not as antiseptics

63. Denature protein by releasing free H+ and OH- ions
and altering the pH of the medium
Uses:
1N NaOH for 1 hour is used for decontamination of
material contaminated with prions
Benzoic acid and salts of Propionic acid are effective
as food preservatives

64. Protein coagulants, have the capacity to combine
with free sulphydryl groups of cell enzymes when
used in appropriate concentrations
Eg.
 Silver sulpha diazene – used on burns
 Silver nitrate(1%) solution- used to prevent
ophthalmia neonatarum in infants
 Copper sulphate- effective fungicide

65. High level disinfectant
Antimicrobial spectrum: Active against a wide range of
microorganisms, including bacteria, yeasts, fungi, viruses,
and spores
Mode of Action Liberates toxic free hydroxyl radicals, Act on cell
membrane lipids, DNA and other cellular components
Uses concentrations from 3% to 6% for disinfecting soft
contact lenses, ventilators, fabrics and endoscopes
Vaporized H2O2 is used for plasma sterilisation
Disadvantage Catalase, produced by organisms can protect
cells from metabolically produced H2O2 by degrading H2O2
to water and oxygen

66.  High level disinfectant and chemical sterilant
 Concentration less than 1% , sporicidal even at low
temperature
 Effective in presence of organic matter and end
products (acetic acid and oxygen) are non toxic
Use:
Often used with hydrogen peroxide to disinfect
hemodialysis units and in plasma sterilization
Disadvantage:
 Corrodes metals

67. Dyes
 Extensively used as skin and wound antiseptic
 Two types: Aniline and Acridine dyes
Aniline dyes:
 Crystal violet, gentian violet, brilliant green, malachite green
 Interferes with synthesis of peptidoglycan
 Decreased activity in presence of organic matter
 Used as selective agents in culture media
Acridine dyes:
 Acriflavine, euflavine, proflavine and aminacrine
 Affected very little by presence of organic matter
 Interferes with nucleic acid synthesis and bacterial proteins
 Not as selective as aniline dyes

68.  Formaldehyde gas
 Betapropiolactone

69. Betapropiolactone (BPL)
 BPL gas (0.2%) is active against all microorganisms
and spores
 More efficient than formaldehyde
 Used for inactivation of vaccines
Disadvantages:
 Low penetrating power
 Carcinogenic

70. Involves five steps after leak testing:
Clean: mechanically clean internal and external surfaces
with water and a detergent or enzymatic cleaners
Disinfect: immerse in high-level disinfectant (or chemical
sterilant) and perfuse disinfectant into all accessible
channels and expose for recommended time

71. Rinse: Items can be rinsed and flushed using sterile water after
high-level disinfection to prevent contamination with organisms
in tap water, such as nontuberculous mycobacteria, Legionella or
gram-negative bacilli such as Pseudomonas .
Dry: with forced air before storage
Store: store the endoscope in a way that prevents
recontamination and promotes drying (e.g., hung vertically)

72.  Phenol coefficient( Rideal walker) test
 Chick martin test
 Kelsey-Sykes test
 In-use test

73. Phenol coefficient test or Rideal walker test
 Phenol is taken as the standard reference material .
 The ratio of the concentration of the disinfectant
being tested to the concentration of the reference
standard required to kill in a specified time .
Chick Martin test
Modification of Rideal Walker test, in this test
disinfectants act in the presence of organic matter to
simulate natural conditions

74. Kelsey- Sykes test or capacity test
It gives a measure of the capacity of disinfectant to retain
its activity when repeatedly used microbiologically
In-use test or Kelsey and Maurer test
It determines whether the chosen disinfectant is effective
for actual use in hospital practice. The efficiency of a
new disinfectant is determined by its ability to inactivate
known number of standard strain of pathogenic
Staphylococci on a given surface within a certain time

75. Devices used for patient care are categorized as
CRITICAL
SEMICRITICAL
NONCRITICAL
- according to the degree of risk for infection
involved in use of the items
- It determines the type of method selected for
disinfection or sterilisation
Spaulding’ s
Classification

76. Level of
Risk
Use Examples Goal
Critical Entry or penetration into
sterile tissue, cavity or
bloodstream
Surgical instruments,
Cardiac/ Urinary Catheters,
Implant, USG probes
Complete
Sterilisation Required
Semi
Critical
Comes in Contact with
mucous membrane or
minor skin breaches.
Respiratory & anaesthestic
equipment; laryngoscopes,
cystoscopes.
Objects to be free of
all micro organisms
but not spores.
Non
Critical
Comes in contact with
intact skin; not mucosa.
Bed pans, BP Cuffs,
Furniture, Bed rails, bedside
table, utensils,
computers
Objects to be clean;
low level disinfection
sufficient

77. LEVEL OF RISK PROCESS
Critical Steam Sterilisation OR Chemical
Sterilants
Semi Critical Sterilization if possible OR High
Level Disinfection using chemicals
like Glutaraldehyde, OPA, PAA, HP
Non Critical Intermediate level/ low level Clean
with soap and water

79. “as that service, with in the hospital, catering for
the sterile supplies to all departments , both to
specialized units as well as general wards and
OPDs.”

80.  To provide medical and surgical equipment that is safe
to use
 To maintain records of processes used and instruments
processed
 To relieve nursing staff of these duties
 To avoid duplication of expensive hospital equipment
 To maintain an inventory of supplies and equipment
 To provide a safe environment for patients and staff
 To keep up to date with developments and advances

81. CSSD
Rinsing
cleanin
g
Drying
checkin
g
sterilizatio
n
Labelin
g
Storage
Issue &
Distributi
on
Receipt

82. 5ml OF
CLEANER IS
ADDED TO 2 L
OF WATER AND
CLEANING
SOLUTION IS
PREPARED.
CLEANING

83. AUTOCLAVE PLASMA STERLIZER

84. 3M™ Steri-Vac™ EO Gas Sterilization Equipment
This Ethylene Oxide gas sterilizer gives operators a
safe, efficient and compact way of sterilizing heat-
sensitive items.

86. LABELLING

87. STORAGE

88. AdvantagesInfection free atmosphere
Maintains standards
Reduces burden on
nursing staff
Prevents cross-
infection
Shortens patient’s
stay
Ensures safe
environment
Quality
care

89. The CSSD can broadly be classified into two parts
Central
unit
Peripheral
unit
Responsible for receiving dirty
Utilities, cleaning, processing,
Sterilization, storage and supply
Mainly responsible for distribution
to various areas of hospital

90. ◦ Separate receiving and issuing counter
◦ The receiving counter must be away from the issue counter
◦ Sterile area should be prior to sterile storage and issue
◦ One way movement from receiving counter to issue counter
◦ There should be no back tracking to sterile goods
There should be minimum six basic divisions in CSSD
Cleaning
Area
Drying Area
Packaging
Area
Sterilization
Area
Storage
Issue
counter

91. STRUCTURAL DESIGNING
The Central Unit comprises of three zones, separated by two distinct barriers.
• One collection window
• one supply window on the other end.
SOILED
ZONE CLEANING
AREA
CLEAN
ZONE
PACKAG
ING
AREA
STERILIZATION
AREA
C
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B
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STERILE
STORAGE
COLLECTION DISTRIBUTION
LOW HIGH

92. EQUIPMENT
• High capacity pass through washer disinfectors at 800C to 900 C having various
shapes and sizes
• Cold and hot water streams
• Detergent solutions
• Steam when available
• Hot air ovens for drying instruments.
• Wall fixtures for drying
• Autoclaves and Hot air ovens
• Ethylene oxide sterilizers
• Testing material to check effectiveness of sterilization.
• Cup boards, selves, tables, chairs, racks
• Trolleys, instrument trays, wire baskets and containers

93. Articles
to be
sterilized
Syringes
Needles
Procedural
Sets
Gloves
I.V.Fluids.
Treatment
Trays.
O.T
Instruments.
O.T. Linen
Infusion
Fluids for
Renal
Dialysis.
At times
LINEN. (other
than O.T)

94. Head of health care facility.
CSSD Manager.
Shift supervisors.
CSSD PERSONNEL.

95.  Disinfection process is one that is intended to significantly
reduce the number of pathogenic microorganisms on
instruments by removing and/or killing them
 Bacterial spores are not necessarily killed by disinfection,
however their numbers may be reduced as a result of the
cleaning process.
 Disinfection may be high level, intermediate level or low
level The level of disinfection required is governed by the
intended use of the item, namely in a ‘non-critical’, ‘semi-
critical’ or ‘critical’ site
 Disinfection should be preceded by thorough mechanical or
manual cleaning

96.  High level disinfection of previously cleaned
instruments and equipment will produce items with
very low likelihood of any pathogenic microorganisms
remaining
 Disinfection may involve chemical or thermal means.
Thermal disinfection, where items can withstand it, is
always preferable to chemical disinfection
 The method of disinfection chosen must be
compatible with the particular equipment and suitable
for the intended use of the equipment