Successfully reported this slideshow.
Your SlideShare is downloading. ×

Sterilization & Disinfection Ghada.pdf

Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Ad
Loading in …3
×

Check these out next

1 of 69 Ad
Advertisement

More Related Content

Recently uploaded (20)

Advertisement

Sterilization & Disinfection Ghada.pdf

  1. 1. Sterilization & Disinfection Dr.Ghada AbdelWahed Ismail Professor of Clinical Pathology Head of Central Infection Control Unit Ain Shams University Hospitals
  2. 2. Intended learning objectives: 1-Define sterilization & sterile object. 2-Define sterility assurance level (SAL). 3-Differentiate between decontamination, cleaning, sterilization & disinfection. 4-Identify methods of decontamination& cleaning. 5-Enumerate methods of packing. 6- List methods of sterilization. 7-List steps of sterilization process.
  3. 3. 8-Enumerate different methods of sterilization. 9-Enumerate different types & conditions of sterilizers. 10-Compare between low temerature sterilizers. 11-Define disinfection & it’s indication. 12-Enumerate different methods of disinfection & their conditions. 13-List levels & steps of disinfection.
  4. 4. Killing all of micro-organisms, including spores. The absence of all viable organisms including viruses and spores
  5. 5. But: Whatever long you apply the sterilizing agent there will be always a fraction that will survive; the number becomes very small, but will never reach zero. Absolute sterility cannot be achieved.
  6. 6. • Research shows that the number of micro- organisms that are killed each minute (or other unit of time) of exposure to the sterilizing agent is a constant percentage of the number of living micro- organisms at the beginning of each minute. i.e when a population of one type of micro-organisms is exposed to a killing agent, not all will die at the same time.
  7. 7. A medical device is considered sterile if the chance that there are viable micro-organisms on the product is less than 1 to a million i-e 10-6
  8. 8. Sterilization can not be achieved unless the device is clean. So there is a chain of processes starting immediately after using medical devices. Each Step is necessary
  9. 9. Used medical device wards / O.R. Storage Control Sterilization Conditioning (packing) Cleaning Decontamination
  10. 10. Definition: it is a method whereby an object or material (surgical instruments or bed linens) is freed of the contaminating agent. Objectives:  To lower Bioburden on the device.  To prevent drying of blood & secretions facilitate cleaning.  To protect staff when handling instruments.  To avoid environmental contamination. Method: - Chemical: Soaking in a detergent. - Thermal : 90 ْ ◌ C > 1 min. 80 ْ ◌ C > 3 min.
  11. 11. i-e Physical removal of dirt, and organic material from the medical device by flushing away in the presence of a detergent.  It is obligatory before any disinfection or sterilization process.  Same detergent used in the decontamination.
  12. 12. Methods: A) Manual. b) Automatic machines : • Washer disinfectors • Ultrasonic cleaner Inspection :  No Stain  No Dirt  No Rust  Functionality of the instrument
  13. 13. Manual cleaning • Done with cold water to avoid denaturation & coaguation of proteins of blood or sputum that make it difficult to remove. • Use PPE. • Done under water to avoid spread of aerosol. • Open locks of instruments & use brush.
  14. 14. • Objectives: To protect sterile equipments. To prevent recontamination before sterilization. • Method using: A-Disposable paper sheets , complying with standard porosity and resistance. B- Bags. C-Containers.
  15. 15. Moist heat (121 - 138 ْ ◌C) • Heat Dry heat (160 - 180 ْ ◌C (250 ْ ◌C) Ethylene oxide (32 - 55 ْ ◌C) • Gas Low temperature steam Formaldehyde (56 - 80 ْ ◌C) γRays (Ambient) • Radiations Electron beam (Ambient) • Plasma Associated with hydrogen peroxide (sterrad) (45 ْ ◌c) Peracetic acid (Plazlyte) (45 ْ ◌c)
  16. 16. • Introduction: • Steam is very effective in transferring heat that can kill micro-organisms at relatively low temperatures in a short time. • To reach such high temperature the steam needs to be pressurized. • Advantage Of Steam: * Can be made quite easily. SAL 10-60 * Clean - not toxic - not corrosive.
  17. 17. Sterilization Process with Fractionated pre-vacuum. 1) Air removal 2) Pressure build-up / Heating up 3) Sterilization 4) Steam release 5) Drying 6) Air admission
  18. 18. 1) Heating up of water and air removal by fractionated: It is an extremely critical phase. In this process, a vacuum is drawn and then a pulse of steam is admitted. The pressure of the pulse could be below or just above the atmospheric pressure.
  19. 19. Both air & steam present in the chamber will be withdrawn & new pulse is admitted. The air fraction inside the chamber become smaller. So the fractionated pre-vacuum process is the most safe sterilization process for all materials in which air can be trapped. At the end of this step the chamber will be filled with the saturated steam (best penetration power)
  20. 20. Effect of Steam Pulsing With each pulse the steam penetrates deeper & deeper
  21. 21. • Air removal by gravity displacement: There is no guarantee for complete air removal. So the steam will be mixed with air unsaturated steam Low penetration power less effective
  22. 22. 2) Building up of pressure: The vessel is sealed & the temperature and pressure increase to the required level. 3) Sterilization time (Holding time). Temperature Pressure Holding time 121 ْ ◌C 1.0 bar 20 min 125 ْ ◌C 1.3 bar 10 - 15 min 134 ْ ◌C 2.05 – 2.04 bar 3 , 3.5 , 4 , 10 ….18
  23. 23. Holding Time: 134 ْ ◌ C - 138 ْ ◌ C : 3.5 min Bowie Dick test. 5-10 min according to the load & the quality of the autoclave. 18 min Creutzfeldt- jakob disease 125 ْ ◌ C : 15 – 20 min for textiles. 121 ْ ◌ C : 20 min for plastic & caoutchouk 1 min at 134 ْ ◌ C is equivalent to 20 min at 121 ْ ◌ C 1 min at 125 ْ ◌ C is equivalent to 2.5 min at 121 ْ ◌ C
  24. 24. 4) Reducing the pressure to atmospheric by releasing the steam. 5) Cooling down of the load & drying by vaccum N.B wet equipment is not sterile.
  25. 25. Control to be operated • Chart record (T ْ ◌ /P ْ ◌ ) • Bowie-Dick test • Chart record (T ْ ◌time) • Temperature sensor • Bowie-Dick test • Chemical indicators (Multiparameter) Steam characteristic • Saturated • Able to kill • Able to penetrate into the deptht of the items
  26. 26. Phase of the cycle • Air removal • Holding time • Steam release & drying Control to be operated • Bowie-Dick test • Chart record • Chart record • Temperature sensors • Chemical indicators (Multi variable parameter) • Chart record • Dryness • Chemical indicators (single variable parameter)
  27. 27. Bowei Dick Test
  28. 28. Control of sterilization process * Log BOOK. * Physical control: 1. Leak test 2. B.D. Steam penetration & distribution. 3.Chart record time, temperature, pressure. * Chemical indicator: strips. * Physico.chemical indicator. * Biological indicators ???
  29. 29. Types of Small Steam Sterilizers (< 54 liters) I. Real Sterilizers * for double wrapped solids, (type B/EN 13 060-2) hollow instrument, & porous products. * vacuum pump or venturi system. * air removal obtained by vacuum and sub / super atmospheric pulses.
  30. 30. Real Sterilizers * Long cycle (40-55min) (type B/EN 13 060-2) at the end of the cycle dry load. Wrapped goods can be stored for use later. * price + + +
  31. 31. II. Steam Disinfectors * for non wrapped solid products. (type N/EN 13 060-3) * air is removed partially by (Flash sterilizer) gravity displacement ! (valve), no pulses. * no drying stage. * short cycle (13-20 min) * price + to + +
  32. 32. III. Sterilizers intended * for non wrapped solid products, for the sterilization and either porous loads or of products specified hollow products, single by the manufacturer wrapped product OR multi (type S/EN 13 060-4) wrapped products &/or drying stage. * gravity displacement or pulses. * price + + to + + +
  33. 33. Applications of use of small sterilizers 1) Type (B) (Vacuum assisted): as any large sterilizer. 2) Type N&S. (non vacuum assisted) (Flash). * In, or immediately near by the operating room. - It is indicated in emergency (in O.R.) when an irreplacable surgical instrument is accidentally contaminated (e.g. falling down). - These machine are not suitable for the routine work. * In Medical clinics. * In all care sectors, when the risk of cross infection exists (e.g: acupuncture) * In dentistry clinics. * In veterinary clinics. * Laboratories.
  34. 34. • Bioburden reduction method:  Inactivation of cells by transfer of heat by dry, hot air.  Inactivation by oxidation.  Temperature 160 – 280 ْ ◌C • Sterilization conditions: (Holding time)  160 ْ ◌C for 120 minutes.  170 ْ ◌C for 60 minutes.  180 ْ ◌C for 30 minutes. • Cycle time :  4 – 10 hours.
  35. 35. • Used for:  Metal instruments.  Glassware, ceramics.  Powders.  Water free oils, greases and fats.  Waxes, paraffin, petrolatum. • Advantages:  Inactivation of pyrogens at temperatures above 250 ْ ◌C.  Non-corrosive.  Simple installation.  Low-cost.
  36. 36. • Disadvantages:  Long process time.  Suitable only for limited range of materials.  Limited packing materials.  Not appropriate for: - Dressings, fabrics - Rubberware. - Sensitive optical equipment.  Shelf life of the sterilized items:* No guarantee.
  37. 37. Dry heat sterilization monitoring * Temperature thermometer * Time time counter Condition of good sterilization in hot air oven: * Homogeneous circulation of air inside. * Equal distribution all over. * No extra – load.
  38. 38. N.B: * All these procedures have no effect on Prions * SAL 10-6
  39. 39. I. Low temperature Steam & Formaldehyde ( LTSF) It is obsolete in many countries. Formaldehyde used as fumigant for many years.  At 1960, its use was exploited as sterilization method. Alone, formaldehyde is slowly sporicidal and insufficiently penetrate for narrow lumen heat labile items. But, when used in conjunction with sub atmospheric steam becomes a far more reliable sterilization process.
  40. 40. Disadvantages 1. Health hazards:  Mutagenic  Carcinogenic  Potent allergen  Irritating odor Although irritant but readily detected at levels below the threshold limit value. 2. Reliability of test spores (2 5 days for the results) 3. Condensation & Gas layering need aeration
  41. 41. Sterilization cycles with LTSF 1. Vacuum <50 mbar for air removal. 2. Steam admission until temperature of 73oC is attained. 3. Introduction of Formaldehyde vapor in a series of pulses (up to 20). 4. Sterilization stage. 5. Withdrawal of Formaldehyde. 6. Steam & air flush.
  42. 42. Loads Suitable For LTSF process • Items that can with stand 80 ْ ◌ C, steam, high vacuum & Formaldehyde. • Paper wrap. • Tube < 3m long. • Metal / plastic complex equipment.
  43. 43. • Fiber optic equipment. • Cotton material. • Porous loads. • Red rubber. • Liquids. • Powders. Loads non suitable for LTSF process
  44. 44. E/O gas is extremely penetrative, non corrosive and highly effective as a sterilizing agent. 2. Ethylene Oxide
  45. 45. Disadvantages: 1. Health hazards : Toxic – Carcinogenic Mutagenic – Mucus mmb irritation. 2. Odourless at concentration < 700 ppm (maximum exposure limit 5 ppm/8 hours period) So, it has to be used with extreme caution.
  46. 46. 3. Explosive & flammable in its pure form. So Safer, non flammable mixture (expensive) Is used: 10% E/0 + 90% CO2 12% E/0 + 88% Freon 12 4. Very long cycle (2 6 up to 20 hours). 5. Long Aeration time for withdrawal of toxic residues on items. Or
  47. 47. E/O Cycles 1. Air removal by vacuum * Chamber heated up to 55o C 2. Subatmospheric steam is introduced to rehumidify the load. 3. Injection & exposure to E/O gas for various times according to pressure, temperature & gas concentration.
  48. 48. 4. Gas is finally removed & the chamber is flushed with air. 5. Aeration time ranged from 12 hrs (in heated cabinet) to 7 days. It depends on : * absorbency of the load. * temperature & air exchange rate.
  49. 49.  What is Plasma? 3. Plasma Sterilization System
  50. 50. It is referred to as the 4th state of the matter ( Solid, liquid, gas & plasma) i.e. There is liberation of free radicals like ions, electron, neutral species+ Energy. • Plasma cloud is globally neutral.
  51. 51. The free radicals are generated from H2O2 in the presence of electromagnetic waves. • Biocidal effect of free radicals: Binding to the functional components of the micro organisms causing their irreversible destruction then the plasma will disintegrate in micro seconds leaving only H2 & O2.
  52. 52. Sterilization Cycle (Plasma) ♣ vacuum (0.4m bar) 10 – 15 min. ♣ Injection of H2O2 in a chamber of about 175 L capacity to obtain a final concentration of 6mg/l (6 min). ♣ Diffusion. ♣ Plasma Phase (15 min). induced by an electromagnetic wave generator, Chamber temperature 45oC± 2oC ♣ Injection ♣ Diffusion ♣ Plasma Phase ♣ Ventilation
  53. 53. * safe & effective for thermo sensitive equipment. * No toxic residue. * Relatively rapid cycle (74 85 min). * No aeration period after sterilization. * Assurance quality. Advantages of sterilization by plasma :
  54. 54. Disadvantages: Not reliable for: ∞ Items made from cellulose (e.g. cotton, paper) absorb water . ∞ Items need to be dry if not cycle cancellation. ∞ Lumens with dead ends. ∞ Highly porous materials. ∞ Long tube ( >2m ) & narrow lumen (<3mm & >30mm long) need a diffusion accelerator
  55. 55. Cycles monitoring: for LTSF, EO & Plasma Sterrad: * Biological indicator : Bacillus stearothermopilus (LTSF & Plasma). Bacillus subtilis (EO). * Chemical indicator : strips. * Physical indicator: Temperature & pressure records.
  56. 56. Comparison of low temperature sterilization Systems H2O2 Gas plasma E/O LTSF 45oC 56oC 80oC Temperature 73o min 4/20 hrs 3- 4 hr Time none High Conc. Used: 400-1000mg/l Toxic.: 10mg/l High Conc. Used: 6mg/l Toxic.: 2mg/l Toxicity none Long Short Airing off V. Good Poor Poor Environ friendly Good V. Good Good Efficiency (Diffusibility) none Slow & irreversible Rapid Reversible Polymerization Computer Control Spores Spores Testing Moderate High Low Cost / Cycle
  57. 57.  Operation with a temporary result leading to the elimination of most of micro-organisms.  Indications : ♣ If the medical device can’t withstand the high temperature of the autoclave. ♣ Semi critical & Non critical devices.
  58. 58. Differences between sterilization & Disinfection • Disinfection 1- 105 Bacteria 105 Spores 104 Fungi 104 Viruses (according to A FNOR standards) i-e if the biobwden is 106 spores after disinfection 101 spores. • Sterilization 1- Reach the level of 10-6 spores whatever the initial biobwden i-e if we start by 106 spores After sterilization 10-6 spores i-e (1 in a million).
  59. 59. • Disinfection 2- No Packaging Used immediately after disinfection. No Security. • Sterilization 2- Packaging So can be used at any time i-e Security
  60. 60. Methods of Disinfection of devices 1) Thermal Disinfection: washer disinfector (60oC 90oC) 2) Chemical Disinfection: i-e Soaking in a disinfectant. 3) Thermo Chemical
  61. 61. Levels and Means of Disinfecting Treatments High Medium Low Activity -Bactericidal -Mycobact. -Fungicidal -Virucidal -Sporicidal -Bactericidal -Mycobact. -Fungicidal -Virucidal -Bactericidal HIV Means -Steam disinfector -2% glutaraldehyde -Formaldehyde -Sodium hypocrite -Peracetic acid -Hydrogen peroxide -Same as before -Washer disinfector -Alcohol (ethanol isopropyl) 70-9% -Phenolic by- products -Same as before -Quaternary Ammoniums -Ampholytics -Aminoacids
  62. 62. Different steps for disinfecting M.D. ☼ Decontamination: For 10 min. ☼ Rinsing: Tap water. ☼ Drying: by clean tissue. ☼ Chemical disinfection: By immersion in a disinfectant solution. ☼ Abundant rinsing using sterile H2O. Or sterile saline to eliminate the residues of the disinfectant solution and to prevent recontamination. ☼ Drying: By sterile tissue or air + alcohol spray.

×