STERILIZATION & DISINFECTION PROCEDURES new - final.pptx

FOR PG TRAINEES

1. STERILIZATION & DISINFECTION PROCEDURES Surg lcdr Chaminda Amarasekara Major Dhirendra Ayer Guide: Col SS JAISWAL

2. SCOPE DEFINITION HISTORICAL PERSPECTIVE SPAULDING CLASSIFICATION METHODS OF STERILIZATION STEPS OF STERILIZATION STERILIZATION MONITORING DISINFECTION 2

3. DEFINITION STERILIZATION Process by which an article, surface or medium is freed of all living micro organisms either in the vegetative or spore state DISINFECTION Destruction or removal of all pathogenic organisms, or organisms capable of giving rise to infections 3

4. HISTORICAL PERSPECTIVE ΄Antisepsis relieved patients from the terror of death and gave to the surgeons …restful nights… and joyous days ΄ William Keen(1837-1932) 4

5. HISTORICAL PERSPECTIVE ANCIENT CIVILIZATION -Used flame ARISTOTLE Advantage of Boiling of drinking water HIPPOCRATES Lightning fires to control plague 5

6. HISTORICAL PERSPECTIVE ROBORT KOCH usefulness of steam for sterilizing surgical instruments and dressings (1878) CHARLES CHAMBERLAND (1851-1908) 6

7. HISTORICAL PERSPECTIVE GASTON POUPINEL 1885 Dry heat sterilization Joseph Lister (1827-1912) A machine that pumped out a fine mist of carbolic acid into the air around an operation 7

8. SPAULDING CLASSIFICATION Strategy for reprocessing contaminated medical devices The system classifies a medical device as critical semi critical noncritical 8

9. SPAULDING CLASSIFICATION CATEGORY DESCRIPTION REQUIREMENT EXAMPLE CRITICAL Enters sterile body cavity or vascular system Sterile Surg instrument, cardiac catheters , implants SEMI-CRITICAL Contacts mucous membrane and non intact skin High level disinfection Endoscope, bronchoscope, Laryngeal mirror, speculum NON- CRITICAL Contacts intact skin Low level disinfection Bed pans, BP cuff, bed rails 9

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13. STEAM STERILIZATION (AUTOCLAVING) Principle – Water boils when its vapour pressure equals that of surrounding atmosphere. Thus when water is boiled in closed vessel at increased pressure, the temperature at which it boils & that of steam which is formed will exceed 100°C. 13

14. STEAM STERILIZATION (AUTOCLAVING) When steam comes in contact with cooler surface, it condenses to water & gives up its latent heat to that surface. Thus 1600ml of steam at 100°C & at atmospheric pressure condenses into 1ml of water at 100°C & releases 518calories of heat 14

15. Air in Autoclave Chamber Air in the chamber will impair sterilization as it is poor conductor of heat & retards the penetration of steam. Efficacy of air removal process can be tested by Bowie-Dick test. 15

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17. STEAM STERILIZATION (AUTOCLAVING) ct.. TYPES OF AUTOCLAVE STERILIZERS Downward Displacement Positive Pressure Displacement Negative pressure Super atmospheric cycles Sub atmospheric cycles 17

18. STEAM STERILIZATION (AUTOCLAVING) ct.. Downward Displacement Also known as a gravity displacement unit. It uses a heating element to heat up the water and produce steam. The steam, which is lighter than air, forces the air inside the sterilization chamber to move downward. Eventually the air moves out through the drain hole of the sterilization chamber. 18

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20. STEAM STERILIZATION (AUTOCLAVING) ct.. Positive Pressure Displacement It uses a separate chamber to create and hold steam. Once sufficient amount of steam is accumulated, it is released into the sterilization unit in a pressurized blast This forces the air to move out through the drain hole and starts the sterilization process. 20

21. STEAM STERILIZATION (AUTOCLAVING) ct.. Negative pressure A vacuum pump sucks air or air/steam mixtures from the chamber. 21

22. STEAM STERILIZATION (AUTOCLAVING) ct.. Super atmospheric cycles achieved with a vacuum pump It starts with a vacuum followed by a steam pulse The number of pulses depends on the particular autoclave and cycle chosen. 22

23. STEAM STERILIZATION (AUTOCLAVING) ct.. Sub atmospheric cycles similar to the super atmospheric cycles chamber pressure never exceeds atmospheric pressure until they pressurize up to the sterilizing temperature 23

24. STEAM STERILIZATION (AUTOCLAVING) ct.. PHASES OF AUTOLAVING Heat Up Phase Sterilization phase Exhaust Phase 24

25. STEAM STERILIZATION (AUTOCLAVING) ct.. PHASES OF AUTOLAVING Heat up Phase Air, if present, should be evacuated before sterilization Vacuum may be applied Sterilization phase Gives latent heat to materials rapidly on contact Microbial destruction will be most effective at these locations Once intended temperature is reached, sterilization time is set 25

26. STEAM STERILIZATION (AUTOCLAVING) ct.. PHASES OF AUTOLAVING Exhaust Phase- At the end the steam should be exhausted from the autoclave to avoid condensation of water on the load when cool air is admitted 26

27. STEAM STERILIZATION (AUTOCLAVING) ct.. Steam criteria Dry: no suspended droplets of water Close to its point of condensation: not superheated Free from air 27

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29. STEAM STERILIZATION (AUTOCLAVING) ct ADVANTAGES Can kill all bacteria, spores & viruses Rapid sterilization Ease of use Good penetration Economical Absence of toxic products/ residues. Materials can be pre-packaged & kept sterile until use 29

30. STEAM STERILIZATION (AUTOCLAVING) ct.. DISADVANTAGES Heat sensitive materials are damaged like plastic & rubber goods. Cause blunting of cutting edges, crossing of metal surfaces. Oil, grease, powders are not sterilized because of lack of penetration. Shortened life of electronic components. 30

31. Articles are packed in special craft papers and then placed in a thermostatically controlled Dry Heat Sterilizer. Mainly suitable for ophthalmic instruments and glass items but not plastics or rubber. It is useful for sterilization of powders, grease, oil and glass syringes. Precaution- temperature is raised and lowered slowly to prevent breakage by uneven expansion. DRY HEAT 31

32. DRY HEATING 32

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34. DRY HEAT 34

35. STEPS OF STERILIZATION Cleaning Manual Mechanical Packaging Loading 35

36. Manual cleaning For instruments which cannot be immersed in water or machine washed orthopedic power drills & saws For instruments that are heat-sensitive laparoscopic & arthroscopic cameras 36

37. MECHANICAL CLEANING Instruments that are heat, moisture, and pressure-sensitive should not be washed in mechanical washers Examples: powered instruments, microsurgical instruments, cameras Ultrasonic baths. 37

38. PACKAGING Once items are cleaned, dried, and inspected, items are wrapped or placed in a rigid container Arranged in tray/basket according to guidelines Hinged instruments opened Items with removable parts should be disassembled Heavy items positioned not to damage delicate items Several choices to maintain sterility of instruments: rigid containers, peel pouched; sterilization wraps 38

39. Packaging An effective sterilization wrap would: Allow penetration of the sterilant Provide an effective barrier to microbial penetration Maintain the sterility of the processed item after sterilization Puncture resistant and flexible Multiple layers are still common practice due to the rigors of handling 39

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41. LOADING Arranged so all surfaces will be directly exposed to the sterilizing agent Allow for proper sterilant circulation; Perforated trays should be placed so the tray is parallel to the shelf Small items should be loosely placed in wire baskets Peel packs should be placed on edge in perforated or mesh bottom racks or baskets 41

42. STERILIZATION MONITARING Sterilization monitored routinely by combination of physical, chemical, and biological parameters Physical - cycle time, temperature, pressure Chemical - heat or chemical sensitive inks that change color when germicidal-related parameters present (Class 1-6) Biological - Bacillus spores that directly measure sterilization 42

43. MONITORING Mechanical Monitors: Devices that record time, temperature & pressure. Biological Indicators : they are standardized preparation of spores. A positive biological indicator is indicative of possible sterilization process failure. They should be used at least once a week but time needed for incubation is long. Eg : spores of Bacillus Stearothermophilus 43

44. BIOLOGICAL MONITORS Steam - Bacillus stearothermophilus Dry heat - B. subtilis ETO - B. atrophaeus New low temperature sterilization technologies HP gas plasma - B. stearothermophilus Ozone -B. stearothermophilus 44

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46. Class 1- These are Internal & External Process Indicator E.g. External Process Indicator – Autoclave Tape. 46

47. Class 2- E.g. Bowie-Dick test for vacuum steam sterilizer. They only assess Vacuum Pump efficiency & detect the presence of air leaks &/or gases in steam. 47

48. Class 3 - E.g. Temperature Tube. Contains chemicals that melts & sometimes changes color when the appropriate temp is attained. Class 4 - Respond to one or more sterilization parameters. Contains Ink that changes color when exposed to correct combination of sterilization parameters. 48

49. Class 5 - Known as Integrating Indicators. Respond to all parameters of sterilization over a specified range of temperatures. Class 6- These are emulating indicators. These are designed to react to all critical parameters over a specified range of sterilization cycles for which the stated values are based on the settings of the selected sterilization cycles

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53. RADIATION Two types of radiations are used NON –IONISING IONISING 53

54. Non- Ionising radiation Eg : UV rays, IR rays Electromagnetic rays with wavelength longer than light Low energy type Absorbed as heat Used in rapid mass sterilisation of prepacked syringes and catheters Used for disinfecting enclosed areas like entryways, operation theatres and laboratories . 54

55. Ionising radiation: Eg ; X- rays, gamma rays & cosmic rays Highly lethal to DNA High penetrative power High energy type No appreciable increase in the temperature – COLD STERILISATION To sterilize plastics, syringes,catheters , swabs. 55

56. HYDROGEN PEROXIDE GAS PLASMA STERILIZATION • Plasma is ionized gas made up of ions and electrons referred to as fourth state of matter •Plasma sterilization operates synergistically via three mechanisms: Free radicals interactions UV radioactive effects Volatilization 56

57. Stage I- vacuum or pre plasma state Low air pressure is achieved and low temperature air plasma is generated Helps remove residual moisture of chamber Stage II- sterilization stage Aqueous solution of H2O2 injected and vaporised Diffuses throughout the chamber, surrounds the items to be sterilized Inactivation of microorganisms by free radicals generated in plasma by breaking apart H2O2 vapours 57

58. Advantages Safe for the environment and staff; it leaves no toxic residuals(water and oxygen). Fast - cycle time is 35-40 min and no aeration necessary Used for heat (process temperature 50 o C) and moisture sensitive items. Simple to operate, install, and monitor. Rubber, plastics,laparoscopic instruments,ureteroscope , cystoscope , bronchoscope,electronic power devices 58

59. Disadvantages Paper, linens and liquids cannot be processed Sterilization chamber is small (volume- 80L) Requires synthetic packaging (polypropylene) and special container tray 59

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61. OTHER STERILIZATION METHODS Ozone – - Sterilises by oxidation - highly reactive - high concentration required to produce sporicidal effects - Conc : 6-12%. Contact time-60min. Disadvantage- - Corrosive when used at high concentrations 61

62. TYPES OF DISINFECTION High-level disinfection - D estroy all microorganisms - L arge numbers of bacterial including spores - Eg : G luteraldehyde , H 2 O 2 Intermediate disinfection - I nactivates Mycobacterium tuberculosis - V egetative bacteria, most viruses, and most fungi - D oes not kill spores - Eg : Alcohol, Phenol, Iodine Low-level disinfection - K ills only vegetative bacteria - F ungi and lipid enveloped viruses - Eg : Q uarternary ammonium compound

63. RADIATION DISINFECTION High energy ionizing radiation destroys microorganisms and is used to sterilize pre packed, single-use, surgical equipment by manufacturers Common sources of radiation include electron beam and Cobalt-60 Disadvantage: Penetrates human tissues. May cause genetic mutations in humans. Industrial large scale setup

64. SATISFACTORY CRITERIA OF CHEMICAL METHODS Active against wide range of organisms and spores N on-corrosive Non-irritant Economical P enetrate grease & fibers Non-toxic P ersistent

65. FACTORS INFLUICING CHEMICAL DISINFECTION Concentration of the Chemical Rate of kill of bacteria varies with the concentration of the disinfectant. b) Temperature Designed to be used at room temperature. c) Evaporation and light deactivation Volatile agents evaporate easily. Exp: Chlorine Products. Exposure to light adversely affects the disinfectant.

66. d) PH Alcohols work best in alkaline PH A ldehydes work best in acidic PH e) Bioburden E ffectiveness depends on the nature and number of microorganisms f) Characteristics of the item to be sterilized: D isinfectant will be effective, if it can contact all the surfaces on the item

67. g) Time D ifferent chemical agents to function effectively varies from seconds to hours. h) Use Pattern, Use Life & Storage Life H ow many times the solution can be used L imited period of time during which activated solution can be used T ime period after which the unused or inactivated product is no longer effective.

68. GLUTRALDEHYDE Saturated di aldehyde High-level disinfectant and chemical sterilant Aqueous solutions of glutaraldehyde are acidic S olution is “activated” (made alkaline) by use of alkalinating agents to pH 7.5–8.5 S helf-life of minimally 14 days Mechanism of action D enaturation of proteins A lkylation of nucleic acid

69. GLUTARLDEHYDE Sterilization Disinfection 8-10 Hrs for - Pneumatic circuits ventilator tubing ,O2 masks nebulizer chamber 15-30 mins for disinfecting endoscopes, Respiratory tubes

70. Advantages Disadvantages • Relatively inexpensive • Easy availability Excellent materials compatibility It kills spores within 12 hrs and viruses within 10 min Respiratory irritation • Pungent and irritating odor • Relatively slow mycobactericidal activity • Coagulates blood and fixes tissue to surfaces • Allergic contact dermatitis

71. PER ACETIC ACID Mixture of hydrogen peroxide and acetic acid H ighly B iocidal oxidizer that maintains its efficacy in the presence of organic soil.

72. Mechanism of action Denatures proteins, disrupts cell wall permeability I nactivate gram-positive and gram-negative bacteria, fungi, and yeasts in <5 minutes

73. Advantage Disadvantage No activation require Less irritation Materials compatibility concerns (lead, brass, copper, zinc) Potential for eye and skin damage

74. HYDROGEN PEROXIDE Advantage Disadvantage No activation required Remove the organic matter, organism • No odor or irritation issues • Does not coagulate blood or fix tissues to surfaces • Inactivates Cryptosporidium Material compatibility concerns (brass, zinc, copper, and nickel/silver plating) both cosmetic and functional • Serious eye damage

75. ORTHO-PTHALALDEHYDE Advantage Disadvantage Fast acting • No activation required • Odour not significant • Excellent materials compatibility • Does not coagulate blood or fix tissues to surfaces Stains skin, mucous membranes, clothing, and environmental surfaces. Hypersensitivity rxn • More expensive than glutaraldehyde • Eye irritation • Slow sporicidal activity

76. ALCOHOL Intermediate level disinfectants 60-90 % Concentration Ethyl alcohol is bactericidal K ill the bacteria but not spores, action against viruses is variable. E xposure to 70% ethanol for 15mins to inactivate the hepatitis virus but 1 min for HIV . E ffectiveness is limited because of rapid evaporation, lack of ability to penetrate organic matter. Used to disinfect external surfaces of equipment like stethoscopes, ventilators, fiberoptic cables

77. CHLORHEXIDINE (SAVLON) Non detergent chemical disinfectant U sually used in the concentration of 0.5% in 70% alcohol for skin. Tubes, masks are sterilized by keeping for 20 min in 0.1% aqueous solution.

78. CHLORINE AND CHLORINE PRODUCTS Intermediate level disinfectants. A ctive against bacteria and viruses but not spores A vailable both in liquid (sodium hypochlorite) and solid (Calcium hypochlorite) forms. W idely used, inexpensive and fast acting. Household bleach is an inexpensive and excellent source of sodium hypochlorite. 1:100 to 1:1000 dilution is effective against HIV 1 : 5 to 1:10 dilution is effective against hepatitis

79. U se is limited by their corrosiveness, inactivation by organic matter R esidue of which causes irritation to skin, eye and respiratory tract Potential hazard is the production of carcinogen bis-chloromethyl ether , when hypochlorite solutions come into contact with formaldehyde. A mixture of hypochlorite with acid will cause rapid evolution of toxic chlorine gas.

80. Cidex is a common designation for variety of solutions with antimicrobial or disinfection purpose Cidex OPA- with ortho-phthalaldehyde Acitivity against mycobacterium Requires no activation Minimal odour Nu- Cidex - with peracetic acid Cidex plus- with gluteraldehyde

81. Sl no Name Concentration 1 Gluteraldehyde 2% 2 Phenol 5% 3 Sodium hypochlorite 0.5-5% 4 Chlorhexidine 1-4% 5 Poviodine iodine 10% 6 Alcohol 70-80% COMMONLY USED CONC OF DISINFECTANTS

82. GASEOUS STERILISATION Ethylene oxide Colorless gas, available as cartridges Toxic and flammable, Odor similar to ether Has an extremely well penetration, even through plastics Powerful sterilizer: Kills all known viruses, bacteria (including spores), and fungi

83. ETHYLINE OXIDE Advantages Effective at killing microorganisms Penetrates medical packaging and many plastics Compatible with most medical materials Disadvantages Potential hazard to patients and staff Lengthy cycle/aeration time

84. GASEOUS CHLORINE DIOXIDE Short lived highly reactive oxidizing gas disrupts proteins Interferes with membrane transport and protein synthesis - Decontamination contact time- 6hrs Presence of organic matter reduces activity

85. FUMIGATION Gaseous sterilization Completely fills the area with gaseous fumigants Kills the microorganism and prevent the growth of microorganism in air, surface, floor Used in Operation theatrs,Hospital,Pharmaceuticals

86. FUMIGANTS Formaldehyde Phosphine 1,3 Dichloropropene Methyl isocyanate Hydrogen cyanide Sulfuryl fluride Iodoform Methyl bromide

87. FORMALDEHYDE GAS seal windows and doors Gas is generated by adding 150mg of KMnO4 to 280ml of formalin for every 1000 cu ft of room volume Room left un open for 48hrs

88. Advantage- inexpensive and easy to handle Broad spectrum efficacy Effective against M. tuberculosis Disadvantage:- Slow acting, time consuming and poor penetration Toxic and carcinogenic

89. COMMONLY USED METHODS Sr no Name of article Method 1 Surgical linen Autoclaving 2 Syringes , needles, catheters, gloves Gamma radiations or ethylene oxide 3 Culture media Autoclaving 4 Glassware , paraffin, glove powder, jellies Hot-air oven 5 Sthethoscope , probes, thermometer alcohol

90. STORAGE OF STERILE ITEMS S torage area should be well-ventilated , provides protection against dust, moisture, and temperature and humidity extremes. Sterile items should be stored so that packaging is not compromised I tems should be labeled with a load number that indicates the sterilizer used, the cycle or load number, the date of sterilization, and the expiration date.

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