This document discusses asepsis, antisepsis, and sterilization techniques. It begins with definitions of asepsis as preventing contact with microorganisms and antisepsis as using chemical disinfectants. Next, it discusses the history starting with Louis Pasteur's germ theory of disease. It then focuses on Joseph Lister who pioneered antiseptic surgery through the use of carbolic acid. The document outlines proper surgical aseptic techniques including scrubbing, gowning, gloving, skin preparation, and draping. It emphasizes maintaining sterility in the operating room through limiting contamination sources and following strict protocols. Finally, it discusses optimizing the operation theatre structure and ventilation to establish different

1. Asepsis, Antisepsis &
Sterilization

2. • Asepsis is the state of being free from disease-
causing contaminants (such as bacteria,
viruses, fungi, and parasites) or, preventing
contact with microorganisms.
• Antisepsis is the use of chemical solutions for
disinfection.

3. History
• Louis Pasteur(1822–
1895) proposed germ
cell theory of disease.
• He stated that disease is
caused by germs –
micro-organisms.
• ‘Father of
microbiology’
19-3

4. Who was Joseph Lister?
• Lister(1827–1912) was the first
to realise that Pasteur’s
Germ Theory had
Implications for surgery.
• He realised the need to kill
the germs in the operating
theatre.
• He developed Antiseptic Surgery
and the results were dramatic.
• Lister tested the results of spraying carbolic
acid on instruments, the surgical incisions, and
dressings with a solution of it.
• It was clear to surgeons that removing
germs from operating theatres was
crucial to lowering death rates.

5. Ignaz Semmelweis (1818–1865) and Oliver
Wendell Holmes (1809–1894)
• Demonstrated that puerperal fever was
carried from patient to patient by doctors.
• Promoted handwashing as a means of
reducing the spread of Puerperal fever to
women in childbirth
5

6. Who was William Halsted?
• Halsted(1852-1922)
emphasised the need
to wear hats, gloves,
masks and
protective clothing
to limit germs in the
operating
environment.

7. Asepsis
Medical
asepsis
Surgical
asepsis

8. Medical asepsis
• Medical asepsis – or clean technique
• includes procedures used to reduce the
number of microorganisms and prevent
their spread.
• It is followed while examining patients ,minor
procedures like I.V cannula insertion..etc

9. Surgical asepsis
• Surgical asepsis or sterile technique
• It is defined as the complete removal of
microorganisms and their spores from the
surface of an object.
• The practice of surgical asepsis begins with
cleaning the object using the principles of
medical asepsis followed by a sterilization
process.

10. Which procedures require surgical
aseptic technique?
• Major & minor surgeries
• Tracheotomy care
• Dressing change
• Catheterization of the urinary bladder..etc

11. Why should we follow aseptic
technique?

12. • Aseptic technique is employed to maximize and
maintain asepsis, thus protecting the patient
from infection & to prevent the spread of the
pathogen.
• Patients with infections or carriers of pathogenic
microorganisms are admitted in the hospital.
• Hospitals house large numbers of people whose
immune systems are often in a weakened state.
• Medical staff move from patient to patient,
providing a way for pathogens to spread.
• Many medical procedures bypass the body's
natural protective barriers.

14. The chain of infection can be interrupted at different levels by
following aseptic techniques

15. Guidelines for maintaining Medical Asepsis
1. Remember that thorough hand washing is the most
important and basic technique for infection control.
2. Always know a patient's susceptibility to infection.
Age, nutritional status, stress, disease processes, and
forms of medical therapy can place patients at risk.
3. Recognize the elements of the infection chain and
initiate measures to prevent the onset and spread of
infection.

16. 4. Never practice aseptic techniques
haphazardly. Rigid adherence to aseptic
procedures is the only way to ensure that a
patient is at minimal risk for infection.
5. Protect fellow health care workers from
exposure to infectious agents. Nosocomial
infections occur with greater frequency when
patients become exposed to health care workers
who are carriers of infection.
6. Be aware of body sites where nosocomial
infection is most likely to develop.

17. Hand hygiene is the
single most important
measure for control
of nosocomial
infections

18. Why it is the single most important
measure??
Healthcare workers can get 100s to 1000s of
bacteria on their hands by doing simple tasks like:
• pulling patients up in bed
• taking a blood pressure or pulse
• touching a patient’s hand
• rolling patients over in bed
• touching the patient’s gown or bed sheets
• touching equipment like bedside rails, overbed
tables, IV pumps

19. Hand Hygiene Techniques
1. Alcohol hand rub
2. Routine hand wash 10-15 seconds
3. Aseptic procedures 1 minute
4. Surgical wash 3-5 minutes

20. Seven
steps of
hand
washing

22. Surgical asepsis

23. • Surgical infections occur during an operation
because –
1. Atmosphere – the air in the ot is
contaminated mainly due to technical issues
– poor design of surgical installations,
irregular air flow between different rooms,
filter deficiency.
2. Staff hygiene – Improper aseptic techniques.
3. Patient - The patient’s own bacterial flora is
the principle source of infection in surgical
wounds.

24. Steps
1) Preparing the patient
2) Surgeon's dress code
3) Scrubbing
4) Gowning
5) Gloving
6) Skin preparation
7) Draping
8) Others – operation theatre structure,
sterilization of instruments…

25. Preparation of the patient
• The preparation of the patient begins with the
preoperative assessment.
• Any focal source of infection should be treated prior to
surgery.
• The patient should be transferred to the theatre
wearing a clean gown in a clean bed or trolley.
• The best time to perform preoperative shaving is
immediately prior to the surgeon scrubbing.
• It should be done by a suitable, trained person to avoid
skin abrasions.

26. BEFORE ENTERING THE OPERATION
THEATRE

27. • Don a scrub suit, and tuck the suit into the pants
or wear a scrub that fits close to the body.
• All hair, beards, or mustaches must be covered
with a surgical cap and mask. Hair must be
confined as it sheds microorganisms with
movement.
• Personal hygiene must be meticulous. A shower
should be taken shortly before beginning a work
day in the operating room or special procedure
area.

28. • Jewelry, long or artificial fingernails, and nail
polish are prohibited as they harbor
microorganisms
• Any body piercing jewelry must be removed as it
may become loose and fall onto the sterile field.
• Shoes must be comfortable with closed heel and
toe and not cloth covered. Cloth-covered shoes
may allow blood, body fluids, and other liquids
to permeate.

30. The Surgical Scrub
• Definition.
• The surgical scrub is the process of removing as
many microorganisms as possible from the hands
and arms by mechanical washing and chemical
antisepsis before participating in a surgical
procedure
• Despite the mechanical action and the
chemical antimicrobial component of the
scrub process, skin is never sterile.

31. Before scrubbing
• Remove all the jewelry to your hands
& trim your nails.
• Do not scrub if u have an infection
or an open wound.

32. The Methodology of the Scrub

33. The Timed Method
• All surgical scrubs are 5 minutes in
length.
– All are performed using a surgical scrub
brush and an antimicrobial soap solution.

34. Surgical Scrub Procedure
1. Wet the hands and
forearms
2. Apply antiseptic agent
from the dispenser to
the hands.
3. Wash the hands and
arms thoroughly to 2
inches above the elbows,
several times. Rinse
thoroughly under running
water with the hands
upward, allowing water to
drip from the flexed
elbows.

35. 4. Take a sterile brush or
sponge (from a package
or dispenser) and apply
an antiseptic agent ( if it
is not impregnated in the
brush). Scrub each
individual finger,
including the nails, and
the hands, a half minute
for each hand.

36. 5. Hold the brush in one
hand and both hands
under running water, and
clean under the
fingernails with a
disposable plastic nail
cleaner. Discard the
cleaner after use.
6. Again scrub each
individual finger,
including the nails and
the hands with the
brush, half a minute for
each hand.

37. The Final Rinse
1. Be sure to keep both
arms in the upright
position (careful not to
touch the faucet!) so that
all water flows off the
elbows and not back down
to the freshly scrubbed
hands. Bring arm through
the water once, starting
with the fingers, then
pull the arm straight out.
Do not let water run
down to hands, must
drip off elbows

38. 7. Rinse the hands and brush, and discard the
brush.
8. Reapply the antimicrobial agent and wash
the hands and arms, applying friction to the
elbows, for 3 minutes. Interlace the fingers
to clean between them.
9. Rinse the hands and arms as described in
the previous slide.

39. Standard scrub solution include :
• 2% chlorhexidine ( effective for more than 4
hours, potent against gram + & gram –
organisms, some viruses, less effective against
tubercle bacilli.
• 7.5% povidone-iodine (duration of effect shorter,
highly bactericidal, fungicidal, viricidal, some
effect against spores and good anti-tubercle
bacilli.
• Alcohols (highly against all except spores)

40. Gowning and Gloving Techniques
1. Reach down to the
sterile package and lift
the folded gown directly
upward.
2. Step back away from the
table into an
unobstructed area to
provide a wide margin of
safety while gowning.
3. Holding the folded gown,
carefully locate the
neckline.

41. 4. Holding the inside front
of the gown just below
the neckline with both
hands, let the gown
unfold, keeping the
inside of the gown
toward the body. Do not
touch the outside of
the gown with bare
hands.
5. Holding the hands at
shoulder level, slip both
arms into the armholes
simultaneously.

42. 6. The circulator brings the
gown over the shoulders
by reaching inside to the
shoulder and arm seams.
The gown is pulled on,
leaving the cuffs of the
sleeves extended over
the hands. The back of
the gown is securely tied
or fastened at the neck
and waist.

43. Gloving
 Gloves have two important functions..
1.Prevent contamination of the surgical
wound.
2.Protect the scrub team from the blood and
body fluids of the patient.
Double gloving reduces the chance of breech in
this protection.
• Double gloving is now a standard part of
‘universal precautions’ for minimising the
transmission of HIV and HEPATITIS B.

44. Gloving by the Closed Glove
Technique
1. Using the right hand(dominant hand)
and keeping it within the cuff of the
sleeve, pick up the left glove from
the inner wrap of the glove package
by grasping the folded cuff.

45. 2. Extend the left forearm
with the palm upward.
Place the palm of the
glove against the palm of
the left hand, grasping in
the left hand the top
edge of the cuff, above
the palm. In correct
position, glove fingers
are pointing toward you
and the thumb of the
glove is down

46. 3. Grasp the back of the
cuff in the left hand
and turn it over the
end of the left sleeve
and hand. The cuff of
the glove is now over
the stockinette cuff
of the gown, with the
hand still inside the
sleeve.

47. 4. Grasp the top of
the left glove and
underlying gown
sleeve with the
covered right hand.
Pull the glove on
over the extended
right fingers until
it completely
covers the
stockinette cuff.

48. 5. Glove the right
hand in the same
manner, reversing
hands. Use the
gloved left hand
to pull on the
right glove.

49. Gloving the Right Hand

50. Scrubbing, Gowning, and Gloving Complete
• Then only you can enter
the sterile field or
prepare the sterile field
over & surrounding the
patient.

51. Remember
• Promptly change a glove punctured
or touched by non-sterile object
during an operation and rinse your
hand with antiseptic solution.
• Re-scrub if the glove has leaked
during puncture.

53. Skin Preparation
• A scrub detergent and/or solution of poviodine
are usually used to clean all surface dirt.
• A sterile towel is placed over the cleaned field to
dry the area.
• The towel is removed from end to end rather
than being lifted up from the center.
• A non-detergent antiseptic, non-alcoholic
iodophor is then painted on, leaving a thin film of
iodophor on the skin. This is done from the
center of the field, working outwards.

55. Draping
 It involves covering the area surrounding the
operative site with sterile barrier material.
 Purpose is to create and maintain a protective
zone of asepsis called a ‘sterile field’.
 Drapes should be handled only by personnel
wearing sterile gloves and should be placed
carefully and not disturbed once placed.
 Drapes should allow access to whole surgical
incision and allow for extensile exposure if
needed.
 Drape materials should resist penetration of
microscopic particles and moisture.

56. Draping for Sterile Procedure
• After the skin has been prepared, place sterile drapes around the
area of operative site
• Must be handled as little as possible
• They must not be flipped or fanned
• Disposable sterile cloth towel are mainly used, however, a
fenestrated drape may be used.
• Place them so that they are within the limits of the area
prepared
• They are folded so that they overlap and the folds face the
operative site.
• are held in place by self-adhesive or by the use of towel clips.

57. Antimicrobial Incise Drapes
• Contain iodophor which is
slowly released on to the skin
surface
• giving continuous and
controlled antimicrobial
activity throughout the
surgical procedure.
• Have a high moisture vapor
transmission rate which allows
the skin to “breathe” ensuring
improved adhesion
throughout the longest
procedures.
• Have superb adhesion right up
to the wound edge.

59. Principles of Surgical Asepsis
• All objects used in the sterile field must be
sterile
• Sterile objects when touched by non-sterile
objects are no longer sterile
• DO NOT reach over the sterile field
• Sterile objects that are out of vision or below
waist level are not sterile.

60. • Sterile objects can become non-sterile by
prolonged exposure to airborne micro-organisms
• Fluids flow in the direction of gravity
• Moisture passing through a sterile object
contaminates the sterile field by capillary action
• The edges of a sterile field are considered non-
sterile (1” surrounding)
• Conscientiousness, alertness & honesty are
essential qualities in maintaining surgical asepsis
• The skin cannot be sterilized & is non-sterile

61. Do you think we attained the ideal
aseptic conditions???
• Not yet!!

62. How to maintain the operation
theatre in aseptic condition

63. Structure of the operation theatre
complex
• Four zones can be described in an O T
complex.
• Based on varying degrees of cleanliness, in
which the bacteriological count progressively
diminishes from the outer to the inner zones
(operating area) and is maintained by a
• differential decreasing positive pressure
ventilation gradient from the inner zone to the
outer zone.

64. (1) Protective zone: It includes
• - Change rooms for all medical and paramedical
• staff with conveniences
• - Transfer bay for patient, material & equipments
• - Rooms for administrative staff
• - Stores & records
• - Pre & post-operative rooms
• - I.C.U. and P.A.C.U.
• - Sterile store

65. (2) Clean zone : Connects protective zone to
aseptic zone and has other areas also like
• - Stores & cleaner room
• - Equipment store room
• - Maintenance workshop
• - Kitchenette (pantry)
• - Firefighting device room
• - Emergency exits
• - Service room for staff

66. (3) Aseptic zone - Includes operation
rooms (sterile)

67. (4) Disposal zone - Disposal areas
from each OR &
corridor lead to disposal zone

68. Structure of the operation theatre
• Operation rooms: The number & size can be
as per the requirement but recommended size
is 6.5 m x 6.5m x 3.5 m.
• Doors : Main door to the OT complex has to
be of adequate width (1.2 to 1.5 m) .
• The doors of each OT should be spring loaded
flap type, but sliding doors are preferred as no
air currents are generated.

69. • All fittings in OT should be flush type and
made of steel.
• The surface / flooring must be slip
resistant, smooth, nonporous, washable,
resistant to disinfectants.
• The corners of walls should be made
rounded to prevent accumulation of dust
and other particulate matter.

70. Temperature & humidity
• Temperature – 22°C-24°C
• Humidity – 50-60%

71. Ventilation
• The microbial free environment is provided in the
operating room by providing filtered and cooled
air under pressure.
• The pressure in the ot should be slightly higher
than the atmospheric pressure to prevent outside
air containing microbes and other particulate
matter.
• The exhaust system if present should be installed
at the floor level because the anesthetic gases
are heavier and the particulate matter containing
microbes settle on the floor.

72. Laminar air flow
• Laminar Air Flow means that the flow of air is
continuous, steady and uni-directional, with
the entire body of air in the room moving with
a low uniform velocity in parallel planes.
• In rooms equipped with Laminar Flow
Patterns, the idea is to have a steady,
turbulence-free flow of absolutely clean air to
bathe the occupants and equipment.

73. • Under this condition of a piston-like delivery of
air, the air will migrate over all surfaces.
• Any contaminated particles will not be picked up
from one spot and deposited in another. Rather,
it will be carried away from the working area to
the Exhaust Point.

75. Reduction of number of persons in the operating
room, a policy of not opening the doors during an
operation and maintaining positive pressure
ventilation are very important in preventing the
infections

76. Maintenance of the operation theatre
Daily cleaning –
At the beginning of the day
• The ot should be cleaned at least one hour
before surgery
• Only remove the dust with cloth wetted with
clean water
• Need not use chemicals/disinfectants.

77. Between procedures in the Operation
Theatres.
• Clean operation tables, theatre equipment with
disinfectant solution with detergent,
• In case of spillage of blood / body fluids
decontaminate with bleaching powder/chlorine
solution ( 10 % available chlorine ).
• Always discard wastes in prescribed plastic bags –
Don’t accumulate biohazard waste in the operation
theatres.
• Don’t discard discarded soiled gowns in the
operation theatre.

78. At the End of the Day
in Operation theatre.
• Clean all the table tops sinks, door handles with
detergent / low level of disinfectant.
• Clean the floors with detergents mixed with warm
water.
• Finally mop with disinfectant like Phenol in the
concentration of 1 : 10
• Keep the ot dry for next day’s work.

79. Weekly maintainence

80. Fumigatation
• Formaldehyde is an Age old compound.
• Kills vegetative bacteria & also the Spore,
viricidal.
• Formaldehyde kills the microbes by alkylating
the amino acids and sulfydral group of
proteins and purine bases.
• When Formaldehyde mixed with water and
exposed to elevated temperature – Gaseous
formaldehyde is generated

81. Creating the Formaldehyde gas
• Electric Boiler Fumigation Method: For Each
1000 cubic.feet of the volume of the
operation theatre 500ml of formaldehyde
(40% solution) added in 1000ml of water in an
electric boiler.
• Switch on the boiler, leave the room and seal
the door for 45 minutes

82. Methods on Fumigation
• Can also be done by
Most easier way to mix the
needed quantity of
Formalin to water and
heating at lower
temperatures at 800c –
900c
Can done also with addition
of Formalin to potassium
permanganate

83. Bacillocid® rasant
• Formaldehyde-free
disinfectant cleaner with low
use concentration.
• Active ingredients: Glutaral
100 mg/g, benzyl-C12-18-
alkyldimethylammonium
chlorides 60 mg/g, didecyl-
dimethylammonium
chloride 60 mg/g.

84. Advantages
• Provides complete asepsis within 30 to 60
minutes.
• Very good cost/benefit ratio
• Good material compatibility
• Excellent cleaning properties
• Virtually no residue

85. ULTRA VIOLET RADIATION
• Daily U.V.
Irradiation for 12 -
16 hrs.
• To be switched off
2 hrs before
surgery.

86. Sterilization
Sterilization is a process by which all
micro organisms like bacteria fungi,
viruses and the bacterial spores are
killed.
Disinfection is the process by which
microorganisms are killed or removed
excepting the bacterial spores.

87. Techniques for sterilisation
 Autoclaving
 Boiling
 Chemical sterilisation
 Gas sterilisation
 Others

88. Autoclaving
• Is a method of sterilization using steam
under high pressure.
• Temperatures of 121 degrees Celsius at
15 lb/sq. inch pressure are standard.
• Metallic instruments for 30 minutes.
• Rubber goods, dressing & linen for 15
minutes
(catheters , gloves , drains etc..)

89. High pressure
autoclaving :
- Suitable for bulk
sterilization.
- Temperatures of 134
degrees Celsius.
- At a pressure of 30lb/
sq. inch for 3 minutes.

90. Boiling
 Boiling for half an hour kills all the bacteria
and its spores.
 Boiling of instruments should be continued for
half an hour after water achieves a
temperature of 100 degrees celsius.
 It is not suitable for sharp instruments as
there is loss of sharpness due to boiling and
there is formation of crust over the
instruments.

91. Chemical sterilization
Sharp instruments are particularly
sterilised by keeping them dipped in
chemicals.
A number of chemicals are used
- 2% glutaraldehyde solution
( cidex )
- lysol
- 70% alcohol
- sterilisation by paracetic acid
(steris)

92. 2% glutaraldehyde solution
( cidex ) :
 For sterilization, instruments should be kept
immersed in cidex for 6hrs.
 For disinfection ,dipping for a period of 15-20
mins is adequate.
 Fibre optic instruments like laparoscope ,
laparoscopic hand instruments , cytoscopes
are sterilised by keeping them in cidex.

93. lysol :
 Used for sterilisation of sharp
instruments.
 Dipping in concenterated lysol for 1
hour is adequate for sterilisation.
 If dilute lysol is used the instrument
should be kept immersed for 24 hrs.

94. 70% alcohol :
• Needles ,unused sutures may be
kept immersed in 70% alcohol for
12 hours for subsequent use.

95. Sterilisation by paracetic acid
( steris )
 This is effective against all micro organisms
including the bacterial spores.
 The method involves immersion of the
instrument in chemical paracetic acid at a
temperature of 50-56 degrees celsius for 12
mins.

96. Gas sterilization
 Ethylene oxide gas : a special chamber is
required for sterilization of instruments using
ethylene oxide gas.
Instruments are kept in the chamber exposed to
the gas for 12hrs.
Large ethylene oxide gas chambers are also used for
industrial sterilization.

97.  Fromaldehyde gas :
Formalin tablets
placed in a formalin
vapouriser lead to
formation of
formaldehyde gas .
Optical
instruments like
cystoscope ,
laparoscope may be
sterilised by keeping
them in formalin
vaporiser for 1 hour.

98. Others
 Gamma irradiation : not applicable for sterilisation of
instruments in operative theatre setup but is useful for
large scale industrial sterilisation.
 Direct flaming : in case of emergency when an
instrument has fallen down form the operation table and
is urgently required , it may be sterilised by direct
flaming.
Instrument is kept in a bowl and and some amount of
spirit is poured and flamed. Temperature reached-1400
degrees.
Not used for sharp instruments.

99.  Hot air oven : ward articles like glass syringes ,
test tubes may be sterilised in a hot air oven.
Keeping the instruments in hot air oven at a
temperature of 160 degrees celsius for 2 hours
is adequate sterilisation by this technique.

100. Ultrasonic cleaner

101. • ULTRA SONIC CLEANER
• USED FOR Cleaning of micro surgical instruments
and instruments with hinged areas and serrated
edges.
• PRINCIPLE -Sound waves pass at a frequency of
100,000hz or more in the liquid. These waves
generate submicroscopic bubbles, which then
collapse creating a negative pressure on the
particles in the suspension.

102. • Bacteria disintegrate and protein
matter is coagulated by this action.
• Not recommended for telescopes,
endoscopes or other lumened devices
such as phaco or irrigation & aspiration
hand pieces.

103. Surveillance of the operation
theatre

104. Surveillance of Operation theatre
Examination of Air
• Estimations are done for
detection of bacteria carrying
particles in Air.
• Frequency ( Once a month)
• Procedure -One plate of blood
agar and sabourauddextrose
agar (SDA) is placed in the
center of the OR (Close to
operation table) and the lid is
kept open for 30 min.
• Blood agar incubated at 37° C
for 48 hrs,&
• SDA incubated at 27° C for 7
days.

105. • Colony counts of bacteria and fungi are
reported.
• Bacterial colony count of more than 10
per plate and fungal colony of more
than one per plate are considered
unacceptable.
• Microbiology department should send
out the reports to OR and maintains
records of the same.