Ent and head neck surgery

1. STERILIZATION AND DISINFECTION
DR AMIYA KUMAR SHAH
MS (ORL-HNS)
RESIDENT – 1st year
GMSMA of ENT and HEAD & NECK STUDIES
MMC- TUTH,IOM

2. ROAD MAP
 Terminology
 Historical background
 Introduction
 Principles
 Types of agents, Mechanism of action
 Advantages and disadvantages
 New disinfectant and sterilization method
 Universal Precautions
 Hand Hygiene
 Methods used in our hospital

3. STERILISATION
Process by which an article, surface or medium is freed of
all living microorganisms, either in the vegetative or spore
state.
Ananthanarayan and Paniker- 6th ed
DISINFECTION
Destruction or removal of all pathogenic organisms or
organisms capable of giving rise to infection.
Ananthanarayan and Paniker- 6th ed

4. DISINFECTANT
Chemicals used to clean inanimate objects to effect
disinfection
ANTISEPSIS
Prevention of infection, usually by inhibiting the growth
of bacteria

5. ANTISEPTICS
Chemical disinfectants applied safely to skin or mucous
membrane, prevent infection by inhibiting the growth of
bacteria or by killing them
SANITISATION
Lowering of microbial counts to prevent transmission in public
setting
(e.g., restaurants & public rest rooms)

6. DEGERMING
Mechanical removal of microbes
e.g., from hands with washing

7. HISTORICAL BACKGROUND
 J. Lister (1827-1972): Carbolic acid (phenols)
 William Stewart Halsted (1852-1922) : Introduction of surgical
gloves
Hippocrates (460-377 BC)

8. APPROACH TO STERILIZATION & DISINFECTION
CRITICAL OBJECTS
Examples : Implants, Vascular
catheters, Needles, Arthroscopes,
Scalpel
SEMI CRITICAL OBJECTS
Examples : Endoscopes,
Endotracheal tubes

9. NON CRITICAL OBJECTS
Examples: Bed sheets , Urinals, Stethescope, Bed
pans

10. CATEGORIES OF DISINFECTANTS
1. STERILIANTS
o Destroy all microorganisms
o 6-10 hours
o For critical items
o Examples : Gluteraldehyde 2%, Hydrogen peroxide, Ethylene oxide

11. Contd…
2. HIGH LEVEL DISINFECTANTS
o Destroy all viruses, vegetative microorganisms
o Do not reliably kill endospores
o 30 min
o For semi critical items
o Examples: Gluteraldehyde, Peracetic acid

12. Contd…
3. INTERMEDIATE LEVEL DISINFECTANTS
o Destroy all vegetative bacteria, fungi and most viruses
o Do not kill endospores even with prolonged exposure
o For non- critical instruments
o Examples : Chlorine, Ammonium compounds

13. Contd…
4. LOW LEVEL DISINFECTANTS
o Destroy fungi, vegetative bacteria except mycobacterium and enveloped
viruses
o Do not kill endospores, naked viruses
o General-purpose
o Examples : Quarternary ammonium compounds, Phenolics

14. BACTERIAL GROWTH
 Exponential growth pattern
 4 phases
 Most susceptible in the log phase

15. Measurement of Microbial Death
 No. of viable cells decreases exponentially with
extent of exposure
 D-Value (decimal reduction value)
dose required to inactivate 90% of initial population
constant

16. Species or strain of micro-organisms
Organisms D – values Time
E. Coli 600C Few mins
Salmonella 600C 1 hr
Staph. aureus 700C <1 min
Staph. epidermis 700C 3 min
bovine spongiform encephalopathy and
Creutzfeldt-Jakob disease – highly resistant-
1340C for 18 min.

17. FACTORS AFFECTING STERILISATION & DISINFECTION
o Prior cleaning of objects
o Organic and inorganic load
o Type and level of microbial contamination
o Concentration and nature of germicide
o Physical nature of objects
o Temperature, pH and Humidity

18. PROCESS
CLEANSING
o Removal of soil or organic material from instruments and
equipments
o Rinsing the object under cold water
o Applying detergent and scrubbing object
o Rinsing the object under warm water
o Drying the object prior to sterilization

19. METHODS OF STERILISATION
PHYSICAL METHODS
 Sunlight
 Drying
 Dry heat: Flaming, Hot air, Incineration
 Moist heat : Pasteurization, Boiling, Steam
 Filtration: Candles, Asbestos pad, Membrane
 Ultrasonic and sonic vibrations

20. CHEMICAL METHODS
 Alcohol: Ethyl ,Isopropyl
 Aldehydes: Formaldehyde, Gluteraldehyde ,
Orthophthaldehyde
 Halogens
 Phenol
 Surface-active agents
 Metallic salts
 Gases : Ethylene oxide, Formaldehyde,
Betapropriolactone

21. PHYSICAL METHODS
SUNLIGHT:
o Appreciable bactericidal activity under natural conditions
o Ultraviolet rays
o Sterilizing power varies according to circumstances
o In tropical countryside
o Example: typhoid bacilli exposed to sunlight killed within 2
hours

22. HEAT:
o Most reliable method
o Whenever possible , should be the method of choice
o Dry/moist/pasteurization
Mechanism of action
o Protein denaturation
o Oxidative damage
o Coagulation of protein

23. Factors responsible
o Nature of heat : Dry/Moist
o Temperature and Time
o Number of organisms present
o Characteristics of organism : Species, Strain, Sporing
capacity
o Nature of material

24. Protein damage

25. DRY HEAT
(A) Flaming
o Uses: Scalpels, needles
(B) Incineration
o Soiled dressing, pathological material
o Plastic such as PVC and polythene (but
polystyrene material emits clouds of dense smoke
and hence should not be incinerated)

26. (c) Hot Air Oven
• Hot air
• Oven heated by electricity with
heating electrode in wall of
chamber
• Fan within the chamber
• Materials evenly placed for free
circulation of air in between
objects

27. Uses:
Forceps, Scissor, Scalpel, Glassware, Liquid paraffin,
Dusting powder, Glycerol
Standing time:
Cutting instruments: 150° C for 2 hours
Others: 160° C for 1 hour

28. MOIST HEAT
o Latent heat liberated when condensed on a cooler surface
o Increased water content on spores : hydrolysis and
breakdown of bacterial protein
o In a moisture free atmosphere, bacterial protein more
resistant to heat
o Moist heat preferred to dry heat for killing

29. PASTEURISATION
Devised by L.Pasteur as a means of
destroying microorganisms that
cause spoilage of milk, wine and beer
Milk:
o Holder method : 63° C for 30 min
o Flash method: 72° C for 15-20 s
followed by rapid cooling to 13° C or
lower

30. o Doesn’t sterilize the milk
o Does kill all disease producing bacteria commonly
transmitted by milk
oMycobacteria,salmonella and brucella are destroyed
oCoxiella burnetii survives Holder method

31. Water Bath
Most non sporing bacteria : 60° C for 30 min
 Staphylococcus aureus and Streptococcus fecalis:
60° C for 60 min
 Vegetative form of bacteria, yeast and moulds:
80°C for 5-10 mins
 Spore of Clostridium botulism (most heat
resistant):120° C for 4 hours
100° C for 330 min
 Viruses: Polio virus: 60° C for 30 min

32. Boiling
o Not recommended for sterilization
o Only as means of disinfecting surgical
instruments
o Vegetative bacteria killed at 90 -
100°C
o Spores require considerable period of
boiling
o Holding time : 10 – 30 min

33. AUTOCLAVE AND STEAM STERILIZER
Principle:
o Usually exposure for 20 min at 121 °C, at a steam pressure of 15 pound for
square inch (psi)

35. DESIGN of AUTOCLAVE
o Vertical or horizontal cylinder
o Made up of gunmetal/stainless steel
o Sheet – iron case
o Lid or door fastened by screw and made
tight by asbestos washer
o Heating done by gas or electricity

36. Vacuum Sterilization Process
o Application of vapour of a mixture of peracetic
acid with hydrogen peroxide and residual gas
from atmospheric air
o Excited by pulsed electrical discharge
o Process of sterilization in vacuum, dry, and at
low temperature (room temperature )

37. FILTRATION
o Used for heat liable liquid to make them microorganism free e.g.
antibiotic solution
o Clinically not used
o Types: candles filters, asbestos filter, membrane filter
o Commonly used for water purifying

38. High Efficiency Particulate Air Filter(HEPA)
o Special filter which
removes nearly all
microorganisms from air
that have a diameter
greater than 0.34 um
o Used in operation
theatres and labs where
potentially dangerous
airborne pathogens such
as mycobacterium are
handled

39. RADIATION
o Electromagnetic waves
o Shorter the wavelength (gamma rays), higher the killing
power
o Non ionizing : infra red and UV rays
o Ionizing : gamma rays
o Damage DNA by producing reactive molecule such as super
oxide and hydroxyl free radical

40. NONIONIZING RADIATION
o Electromagnetic rays with wavelength longer than that of visible
light
o Some are absorbed as heat
e .g., Infrared : Rapid sterilization of syringe
o Ultraviolet: Disinfecting enclosed area : hospital wards , OT,
virus lab
IONIZING RADIATION
o Highly lethal to DNA and other cell constituents
o High penetrating power
o No increase in temperature: Cold sterilization
e.g., X ray, Gamma rays, Cosmic rays
o Gamma rays: Plastic syringe, Catheters, Metal foils

41. CHEMICAL METHODS
- Different chemical agents used
- An ideal agent
o Wide spectrum
o Speedy action
o Active in presence of organic matter, acid, alkali
o Stable and high penetrating power
o Non irritant, non toxic, non interfering with healing
o Cheap, safe, and easy to use

42. EVALUATION OF DISINFECTANT
Phenol coefficient
o Compares efficacy to that of phenol
o With greater efficacy indicated with coefficient
>1
o Salmonella typhi and Staphylococcus aureus
commonly used to determine coefficients
Disc diffusion method
o Placement of disinfectant impregnated filter
paper on well-inoculated agar

43. MECHANISM OF ACTION
o Protein coagulation
o Disruption of cell
membrane
o Damage to nucleic acid
o
o Substrate competition

44. ALCOHOL
Mechanism
o Denaturation of protein
o Change in cell membrane
Agents
o Ethyl alcohol (Ethanol)
o Isopropyl alcohol
- Not reliable agents for sterilization
- Unable to kill spores at normal temperature
- Evaporate quickly which limit their effective contact time
and so their germicidal effectiveness

45. ETHANOL
o Used mainly as skin antiseptics
o Bactericidal action
o Remove lipid from skin
o Conc. of 60-70 % in water effective
ISOPROPYL ALCOHOL
o Bactericidal activity slightly greater than that of ethanol
o Less volatile
o Recommended as a replacement for ethanol
o Toxic effect greater and longer than produced by ethanol like necrosis

46. USES
o As antiseptic to prepare skin for procedure such as injection that
breaks the intact skin
o As disinfectants for treating instrument
o May damage some material like rubber

47. ALDEHYDES
Mechanism
o Alkylating agents acts on protein
o cause enzyme modification and inhibition
FORMALDEHYDE
 In aqueous sol:
 Markedly bactericidal , sporicidal and Virucidal effect
Uses
10 % formaldehyde
- To clean metal instrument
- Preserve anatomical bodies
Formalin:
- An aqueous sol of 37 % formaldehyde
- 0.2% to 0.4% formalin
- Used to inactivate viruses for vaccine preparation

48. OT FUMIGATION:
o After sealing windows and other outlet
o 150 gm of Kmno4 and 280ml of formalin is mixed to
generate formaldehyde gas
o After generating vapour, door is sealed for 48 hours

49. GLUTERALDEHYDE
o Action similar to formaldehyde
o Specially effective against tubercle bacilli, fungi and
virus
o 10 times more potent than formaldehyde
o Less toxic and irritant to eyes and skin
o No deleterious effect on lenses of instrument such as
cystoscope and bronchoscope
Uses
2 % gluteraldehyde as cold steriliant for surgical
instrument
-Endoscopes
-Endotracheal tube
-Metal instrument
-Polythene tubing

50. o Immersion for 10 -12 hours: destroy all form of
microbial life including endospores and virus
o 10 min: destroy vegetative bacteria
o Toxic,thorough rinsing of treated items before use

51. HYDROGEN PEROXIDE
o Oxidizing Agent
o 3 % sol harmless but weak antiseptic
o Use: Cleaning of wound
Mechanism
Toxic free hydroxyl radical which damage DNA
Uses
Disinfection of surgical devices , soft plastic contact lens

52. Halogens
o Bactericidal, also active against viruses
o In water supplies, swimming pool,
food and dairy industry
o Too irritating to skin and mucous
membrane to be used as antiseptic
o e.g. 5% sodium hypochlorite
used to disinfect instrument

53. o Chlorites/ Hypochlorites
o Broad-spectrum, inexpensive
o Disinfectant of choice – viruses and HBV
o Inactivated by organic matter, corrode metals, bleaching
action

54. Iodine
o Inactivated by organic matter
o Staining and hypersensitivity
o Iodophors – iodine + anionic detergent
o Povidine iodine – iodine + polyvinyl pyrrolidone
o Tincture – iodine + alcohol
o Less irritant and staining
o Skin disinfection and pre-operative preparation of
skin

55. IODOPHORES
Iodine is linked to carrier molecule that release free iodine
slowly
 Carriers increase the solubility of iodine and provide
sustained release reservoir of halogen
 Iodophores are not as irritating to skin as tincture iodine
nor are they as likely to stain
Example:Betadine
Compound of 1-vinyl-2-pyrrolidine polymer with iodine not
less than 9% and not more than 12% available iodine

56. Phenolics
o First used by Lister in 1865
o Prepared by distillation of coal tar between 170 and 270 °C
o Highly corrosive and toxic
MOA
o High conc.: Damage of cell membrane
o Low conc.: precipitate protein and membrane bound oxidase and
dehydrogenase

57. Types
1. Lysol and cresol
2. Chlorophenol and chloroxyphenols
Lysol and Cresol:
o Not readily inactivated by presence of organic matter
o Good disinfectant
Chlorophenol and Chloroxyphenols:
o Less toxic
o Less active and more readily inactivated by organic matter
Uses: Disinfecting ward
Mixed with soaps/ various cosmetic preparation

58. Chlorhexidine
o Commonly used – skin and mucous membrane
o Less active – Gm –ve bacteria like Pseudomonas and
Proteus, limited virucidal, tuberculocidal and negligible
sporicidal
o Combined with detergent/alcohol – handwashing/ hand
rub

59. o Low irritant and low toxic
o Inactivated by organic matter, soap, anionic detergents
and hard water

60. Gaseous Processes
 Ethylene Oxide:
o Alkylating agent
o Highly penetrative, non-corrosive
microbicidal gas
o Gas conc. – 7000-1000 mg/l at 45-600C
and relative humidity above 70% for 2 hrs

61. Contd…
 MOA- reacts with protein, DNA and RNA
 Uses: used in industry for single-use items, heat sensitive
medical devices like tracheostomy tube, prosthetic heart
valves, plastic catheters

62. NEW DISINFECTANT AND STERILIZATION METHODS
Disinfection:
Ortho-phthaladehyde (OPA)
Superoxide water (sterilox)
Sterilization
Liquid sterilization process (endocleans)
New plasma sterilizer (sterrad 50)
E Beam sterilisation

63. OPA: ORTHO-PHTHALADEHYDE
o Clear pale blue liquid
o Conc.: 0.55%
o Superior to glutaraldehyde
Advantage over glutaraldehyde
 Requires no activation
 Non irritant to eyes and nasal passage
 Stability over wide range of pH (3-9)
 Barely perceptible odour
 Standing time (12 hours Vs 12 min)
Disadvantage
o Stains protein gray (including unprotected
skin), thus be handled with caution
o High cost
Immersion time: At 200C 12 min by FDA (varies
from 5 to 12 min)

64. SUPEROXIDE WATER
o Concept is electrolyzing saline to create disinfectant
o Saline passed over titanium –coated electrodes
o Main products are hypochlorous acid and free chlorine radicals
o Product generated has PH of 5 to 6.5
o Disinfectant is generated at point of use
o Contact time :<2 min
Advantages
o Basic material (saline and electricity) are inexpensive
o Non toxic to biological tissue
Disadvantages
o Production equipment are expensive
o Limited use life (must be freshly generated)

65. ENDOCLEANS
o Computer controlled endoscope – reprocessing
machine
o A system designed to provide rapid, automated, point
of use sterilization
o It contains performic acid (hydrogen peroxide and
formic acid)
Advantages
o Device automatically cleans and sterilizes
o Rapid cycle time ( < 30 min)
Disadvantages
o Use of immersible instrument only
o Point of use system, no longer storage

66. HYDROGEN PEROXIDE PLASMA
o Low temperature sterilization technology
o For temp sensitive equipment
o Process involves: Sterilization in a chamber using
H2O2 vapour diffusion
o As effective as ethylene oxide
o Contact time : 45 min to 72 min
Advantages
o Reduced cycle time: 45 min
 Disadvantages
o Costly
o Endoscope with length > 40 cm or less than 3 mm can’t
be processed

67. E-beam sterilisation
o Ascribed to have the shortest process
cycle of any currently recognized sterilization
method
o In E-beam processing, the products are
scanned for seconds, within the radiation
shielding
o Overall process time 5 to 7 minutes
o With the use of established and recognized
dosimetric release procedures, a product can
be released from quarantine as sterile within
30 minutes

68. IN OPD
Glutaraldehyde
BOILING
ALCOHOL
POVIDINE IODINE

69. IN WARD
ALCOHOL
Chlorine
POVIDINE IODINE
Glutaraldehyde

70. 0T

71. IN OT
AUTOCLAVE
OPA
FORMALDEHYDE GAS
ETHYLENE OXIDE
ALCOHOL
POVIDINE IODINE

72. o Surgical instrument (METALLIC) : Autoclave
OPA
o Plastic, rubber (suction tube, cautery): Formaldehyde gas
o IMPLANT:
o Gel foam: Ethylene gas, Hot air oven
o Grommet, Teflon piston: Autoclave
o Lacrimal (DCR stent) ET tube, Syringe, Drain (romovac), NG
tube: Gas, Ethylene oxide
o Surgical blade: Gamma radiation
o Suture material: 90% isopropyl alcohol
o IV cannula, syringe: Gamma radiation
o OPD (examination) instrument: Boiling

73. o OT: Ethylene oxide, autoclave, formaldehyde gas, OPA,
alcohol and povidine iodine
o WARD: Chlorine, alcohol, glutaraldehyde and povidine
iodine
o OPD: Alcohol, Boiling, glutaradehyde and povidine iodine.

74. STERILISATION OF HIV CONTAMINATED OBJECTS AND SURFACES
o Always sterilise instruments and re-usable needles after each
use
o Place instruments in a 0.5% chlorine solution after use to
prevent fluids from becoming dry and difficult to remove
o Wash well with a brush and soapy water

75. Methods
o Steam under pressure for at least 20 minutes.
o Heat in an electric oven for 2 hours at 170°C (340°F).
o Boil in water for 20 minutes
o Soak in one of the chemicals listed for 30 minutes. ( not suitable for
sterilising needles and syringes.)
Povidone iodine 2%
Chloride solution 0.5%
Glutaraldehde 2%
Rubbing alcohol 70%
Hydrogen peroxide 6%
(Disinfectants such as Lysol, Savlon and Dettol will not kill HIV virus )

76. o Disinfect surfaces and bedding
o Wipe surfaces with one of the chemicals which kill HIV if
there are spills of blood and fluid
o Cover blood and vomit spillages with one of these
chemicals
o leave for a few minutes first and then clean up, wearing
gloves
o Burn cleaning materials or disinfect them

77. UNIVERSAL PRECAUTIONS
o Consider every person potentially infectious
o Wash hands
o Wear gloves
o Use physical barriers
o Use antiseptic agents
o Use safe work practice
o Safely dispose infectious wastes
o Process used items

78. Key components
o Hand washing
o Gloves
o Masks and Goggles
o Gowns
o Linen
o Patient care equipments
o Environmental cleaning
o Sharps
o Patient resuscitation
o Patient placement

79. HAND HYGIENE
o Hand washing
o One of the most important
procedures for preventing
the spread of disease
o Principle route by which
cross infection occurs
(Elliot P.R.A. 1992 )

80. Choice of cleansing agent
o Antiseptic Solutions
o Alcohol Gel
o Chlorhexidine Gluconate
o Povidine Iodine

81. Correct hand wash technique
o A six-step hand washing technique has been
devised by Ayliffe et al ,1992
o Wet hands under running water
o Dispense one dose of soap into cupped hands
o Hand wash for 10-15 seconds vigorously and
thoroughly, without adding more water
o Rinse hands thoroughly under running water
o Dry hands with disposable paper towel

82. Six-step hand wash technique:
 Rub palm to palm
 Right palm over left dorsum and left
palm over right dorsum
 Palm to palm fingers interlaced
 Back of fingers to opposing palms with
fingers interlaced
 Rotational rubbing of right thumb
clasped in left palm and vice versa
 Rotational rubbing back and forwards
with clasped fingers of right hand in
left palm and vice versa

84. THANK YOU !!!