sterilistion_n_disinfection_own_-_Copy.ppt

Ent and head neck surgery

1. STERILIZATION AND DISINFECTION
DR AMIYA KUMAR SHAH
MS (ORL-HNS)
RESIDENT –1
st
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
Processby which an article, surface or medium is freed of
all living microorganisms, either in the vegetative or spore
state.
Ananthanarayanand Paniker-6
th
ed
DISINFECTION
Destruction or removal of all pathogenic organisms or
organisms capable of giving rise to infection.
Ananthanarayanand Paniker-6
th
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
oDestroy all microorganisms
o6-10 hours
oFor critical items
oExamples : Gluteraldehyde2%, Hydrogen peroxide, Ethylene oxide

11. Contd…
2. HIGH LEVEL DISINFECTANTS
oDestroy all viruses, vegetative microorganisms
oDo not reliably kill endospores
o30 min
oFor semi critical items
oExamples: Gluteraldehyde, Peraceticacid

12. Contd…
3. INTERMEDIATE LEVEL DISINFECTANTS
oDestroy all vegetative bacteria, fungi and most viruses
oDo not kill endosporeseven with prolonged exposure
oFor non-critical instruments
oExamples : Chlorine, Ammonium compounds

13. Contd…
4. LOW LEVEL DISINFECTANTS
oDestroy fungi, vegetative bacteria except mycobacterium and enveloped
viruses
oDo not kill endospores, naked viruses
oGeneral-purpose
oExamples : Quarternaryammonium 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 –valuesTime
E. Coli 60
0
C Few mins
Salmonella 60
0
C 1 hr
Staph. aureus 70
0
C <1 min
Staph. epidermis70
0
C 3 min
bovine spongiform encephalopathy and
Creutzfeldt-Jakob disease –highly resistant-
134
0
C for 18 min.

17. FACTORS AFFECTING STERILISATION & DISINFECTION
oPrior cleaning of objects
oOrganic and inorganic load
oType and level of microbial contamination
oConcentration and nature of germicide
oPhysical nature of objects
oTemperature, pH and Humidity

18. PROCESS
CLEANSING
oRemoval of soil or organic material from instruments and
equipments
oRinsing the object under coldwater
oApplying detergent and scrubbing object
oRinsing the object under warm water
oDrying 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:
oAppreciable bactericidal activity under natural conditions
oUltraviolet rays
oSterilizing power varies according to circumstances
oIn tropical countryside
oExample: typhoid bacilli exposed to sunlight killed within 2
hours

22. HEAT:
oMost reliable method
oWhenever possible , should be the method of choice
oDry/moist/pasteurization
Mechanism of action
oProtein denaturation
oOxidative damage
oCoagulation of protein

23. Factors responsible
oNature of heat : Dry/Moist
oTemperature and Time
oNumber of organisms present
oCharacteristics of organism : Species, Strain, Sporing
capacity
oNature of material

24. Protein damage

25. DRY HEAT
(A) Flaming
oUses: Scalpels, needles
(B) Incineration
oSoiled dressing, pathological material
oPlastic 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
oLatent heat liberated when condensed on a cooler surface
oIncreased water content on spores : hydrolysis and
breakdown of bacterial protein
oIn a moisture free atmosphere, bacterial protein more
resistant to heat
oMoist heat preferred to dry heat for killing

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

30. oDoesn’t sterilize the milk
oDoes kill all disease producing bacteria commonly
transmitted by milk
oMycobacteria,salmonellaand brucellaare destroyed
oCoxiellaburnetiisurvives Holder method

31. Water Bath
Most non sporing bacteria : 60°C for 30min
Staphylococcus aureus and Streptococcus fecalis:
60°C for60 min
Vegetative form of bacteria, yeast and moulds:
80°C for 5-10mins
Spore of Clostridium botulism (most heat
resistant):120°C for 4hours
100°C for 330min
Viruses: Polio virus: 60°C for 30min

32. Boiling
oNot recommended for sterilization
oOnly as means of disinfecting surgical
instruments
oVegetative bacteria killed at 90 -
100°C
oSpores require considerable period of
boiling
oHolding time : 10 –30 min

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

35. DESIGN of AUTOCLAVE
oVertical or horizontal cylinder
oMade up of gunmetal/stainless steel
oSheet –iron case
oLid or door fastened by screw and made
tight by asbestos washer
oHeating done by gas or electricity

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

37. FILTRATION
oUsed for heat liable liquid to make them microorganism free e.g.
antibiotic solution
oClinically not used
oTypes: candles filters, asbestos filter, membrane filter
oCommonly used for water purifying

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

39. RADIATION
oElectromagnetic waves
oShorter the wavelength (gamma rays), higher the killing
power
oNon ionizing : infra red and UV rays
oIonizing : gamma rays
oDamage DNA by producing reactive molecule such as super
oxide and hydroxyl free radical

40. NONIONIZING RADIATION
oElectromagnetic rays with wavelength longer than that of visible
light
oSome are absorbed as heat
e .g., Infrared : Rapid sterilization of syringe
oUltraviolet: Disinfecting enclosed area : hospital wards , OT,
virus lab
IONIZING RADIATION
oHighly lethal to DNA and other cell constituents
oHigh penetrating power
oNo increase in temperature: Cold sterilization
e.g., X ray, Gamma rays, Cosmic rays
oGamma 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
oCheap, safe, and easy to use

42. EVALUATION OF DISINFECTANT
Phenol coefficient
oCompares efficacy to that of phenol
oWith greater efficacy indicated with coefficient
>1
oSalmonella typhiand Staphylococcus aureus
commonly used to determine coefficients
Disc diffusion method
oPlacement 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
oDenaturationof protein
oChange in cell membrane
Agents
oEthyl alcohol (Ethanol)
oIsopropyl 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
oUsed mainly as skin antiseptics
oBactericidal action
oRemove lipid from skin
oConc. of 60-70 % in water effective
ISOPROPYL ALCOHOL
oBactericidal activity slightly greater than that of ethanol
oLess volatile
oRecommended as a replacement for ethanol
oToxic effect greater and longer than produced by ethanol like necrosis

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

47. ALDEHYDES
Mechanism
oAlkylatingagents acts on protein
ocause enzyme modification and inhibition
FORMALDEHYDE
In aqueous sol:
Markedly bactericidal , sporicidaland Virucidaleffect
Uses
10% formaldehyde
-To clean metal instrument
-Preserve anatomical bodies
Formalin:
-An aqueous sol of 37% formaldehyde
-0.2% to0.4% formalin
-Used to inactivate viruses for vaccine preparation

48. OT FUMIGATION:
oAfter sealing windows and other outlet
o150 gm of Kmno4 and 280ml of formalin is mixed to
generate formaldehyde gas
oAfter generating vapour, door is sealed for 48 hours

49. GLUTERALDEHYDE
oAction similar to formaldehyde
oSpecially effective against tubercle bacilli, fungi and
virus
o10 times more potent than formaldehyde
oLess toxic and irritant to eyes and skin
oNo 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. oImmersion for 10 -12 hours: destroy all form of
microbial life including endospores and virus
o10min: destroy vegetative bacteria
oToxic,thorough rinsing of treated items before use

51. HYDROGEN PEROXIDE
oOxidizing Agent
o3% sol harmless but weak antiseptic
oUse: Cleaning of wound
Mechanism
Toxic free hydroxyl radical which damage DNA
Uses
Disinfection of surgical devices , soft plastic contact lens

52. Halogens
oBactericidal, also active against viruses
oIn water supplies, swimming pool,
food and dairy industry
oToo irritating to skin and mucous
membrane to be used as antiseptic
oe.g. 5% sodium hypochlorite
used to disinfect instrument

53. oChlorites/ Hypochlorites
oBroad-spectrum, inexpensive
oDisinfectant of choice –viruses and HBV
oInactivated by organic matter, corrode metals, bleaching
action

54. Iodine
oInactivated by organic matter
oStaining and hypersensitivity
oIodophors –iodine + anionic detergent
oPovidine iodine –iodine + polyvinyl pyrrolidone
oTincture –iodine + alcohol
oLess irritant and staining
oSkin 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
oFirst used by Lister in 1865
oPrepared by distillation of coal tar between 170 and 270 °C
oHighly corrosive and toxic
MOA
oHigh conc.: Damage of cell membrane
oLow conc.: precipitate protein and membrane bound oxidase and
dehydrogenase

57. Types
1. Lysol and cresol
2. Chlorophenol and chloroxyphenols
Lysol and Cresol:
oNot readily inactivated by presence of organic matter
oGood disinfectant
Chlorophenol and Chloroxyphenols:
oLess toxic
oLess active and more readily inactivated by organic matter
Uses: Disinfecting ward
Mixed with soaps/ various cosmetic preparation

58. Chlorhexidine
oCommonly used –skin and mucous membrane
oLess active –Gm –vebacteria like Pseudomonas and
Proteus, limited virucidal, tuberculocidaland negligible
sporicidal
oCombined with detergent/alcohol –handwashing/ hand
rub

59. oLow irritant and low toxic
oInactivated by organic matter, soap, anionic detergents
and hard water

60. Gaseous Processes
Ethylene Oxide:
oAlkylating agent
oHighly penetrative, non-corrosive
microbicidal gas
oGas conc. –7000-1000 mg/l at 45-60
0
C
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
oClear pale blue liquid
oConc.: 0.55%
oSuperior 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
oStains protein gray (including unprotected
skin), thus be handled with caution
oHigh cost
Immersion time: At 20
0
C 12 min by FDA (varies
from 5 to 12 min)

64. SUPEROXIDE WATER
oConcept is electrolyzing saline to create disinfectant
oSaline passed over titanium –coated electrodes
oMain products are hypochlorous acid and free chlorine radicals
oProduct generated has PH of 5 to 6.5
oDisinfectant is generated at point of use
oContact time :<2 min
Advantages
oBasic material (saline and electricity) are inexpensive
oNon toxic to biological tissue
Disadvantages
oProduction equipment are expensive
oLimited use life (must be freshly generated)

65. ENDOCLEANS
oComputer controlled endoscope –reprocessing
machine
oA system designed to provide rapid, automated, point
of use sterilization
oIt contains performic acid (hydrogen peroxide and
formic acid)
Advantages
oDevice automatically cleans and sterilizes
oRapid cycle time ( < 30 min)
Disadvantages
oUse of immersible instrument only
oPoint of use system, no longer storage

66. HYDROGEN PEROXIDE PLASMA
oLow temperature sterilization technology
oFor temp sensitive equipment
oProcess involves: Sterilization in a chamber using
H2O2 vapour diffusion
oAs effective as ethylene oxide
oContact time : 45 min to 72 min
Advantages
oReduced cycle time: 45 min
Disadvantages
oCostly
oEndoscope with length > 40 cm or less than 3 mm can’t
be processed

67. E-beam sterilisation
oAscribed to have the shortest process
cycle of any currently recognized sterilization
method
oIn E-beam processing, the products are
scanned for seconds, within the radiation
shielding
oOverall process time 5 to 7 minutes
oWith 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. oSurgical instrument (METALLIC): Autoclave
OPA
oPlastic, rubber (suction tube, cautery):Formaldehyde gas
oIMPLANT:
oGel foam: Ethylene gas, Hot air oven
oGrommet, Teflon piston:Autoclave
oLacrimal (DCR stent) ET tube, Syringe, Drain (romovac), NG
tube: Gas, Ethylene oxide
oSurgical blade: Gamma radiation
oSuture material: 90% isopropyl alcohol
oIV cannula, syringe:Gamma radiation
oOPD (examination) instrument:Boiling

73. oOT: Ethylene oxide, autoclave, formaldehyde gas, OPA,
alcohol and povidine iodine
oWARD: Chlorine, alcohol, glutaraldehyde and povidine
iodine
oOPD: Alcohol, Boiling, glutaradehyde and povidine iodine.

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

75. Methods
oSteamunder pressure for at least 20 minutes.
oHeatin an electric oven for 2 hours at 170°C (340°F).
oBoilin water for 20 minutes
oSoakin one of the chemicals listed for 30 minutes. ( notsuitable 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. oDisinfect surfaces and bedding
oWipe surfaces with one of the chemicals which kill HIV if
there are spills of blood and fluid
oCover blood and vomit spillages with one of these
chemicals
oleave for a few minutes first and then clean up, wearing
gloves
oBurn cleaning materials or disinfect them

77. UNIVERSAL PRECAUTIONS
oConsider every person potentially infectious
oWash hands
oWear gloves
oUse physical barriers
oUse antiseptic agents
oUse safe work practice
oSafely dispose infectious wastes
oProcess used items

78. Key components
oHand washing
oGloves
oMasks and Goggles
oGowns
oLinen
oPatient care equipments
oEnvironmental cleaning
oSharps
oPatient resuscitation
oPatient placement

79. HAND HYGIENE
oHand washing
oOne of the most important
procedures for preventing
the spread of disease
oPrinciple route by which
cross infection occurs
(Elliot P.R.A. 1992 )

80. Choice of cleansing agent
oAntiseptic Solutions
oAlcohol Gel
oChlorhexidine Gluconate
oPovidine Iodine

81. Correct hand wash technique
oA six-step hand washing technique has been
devised by Ayliffe et al ,1992
oWet hands under running water
oDispense one dose of soap into cupped hands
oHand wash for 10-15 seconds vigorously and
thoroughly, without adding more water
oRinse hands thoroughly under running water
oDry 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 !!!