quality control of sterilization.pptx........

Quality control of sterilization

1. quality control of sterilization DR. VEERENDRA MARAVI JR-2 , DEPT OF MICROBIOLOGY

2. contents History Introduction Sterilization process monitoring Sterilisation indicators physical indicators chemical indicators biological indicators Process challenge device (PCD) Documentation conclusion

3. History a French physicist, Denis Papin , invented the “Digester” in 1680. This was a type-of pressure cooker . In 1876, John Tyndall, an English physicist, discovered heat-resistant bacteria and later originated the method of fractional sterilization by discontinuous (intermittent) heating. In the same year, a student of Louis Pasteur, Charles Chamberland developed the first pressure steam sterilizer, or autoclave. in 1881, the research of Robert Koch and his team brought forth the disinfecting properties of steam and hot air At this point, monitoring or evaluation of the sterilization process was not performed

4. IT IS SAID THAT IN EARLIER DAYS A RAW POTATO WAS SOME TIME PLACED IN STERILIZER ALONG WITH THE LOAD BEING PROCESSED AND AFTERWARD EXAMINING TO SEE IF IT WAS COOKED, IF IT IS ,THEN THE LOAD WAS CONSIDERED STERILE

5. STERILIZATION Process by which all living microorganisms including viable spores, are either destroyed or removed from an article, body surface or medium. Reduction of at least 10 6 log CFU of microorganisms .

6. STERLITY ASSURANCE The Association for the Advancement of Medical Instrumentation (AAMI) has been instrumental in defining the term Sterility Assurance Level . The SAL is normally expressed as 10 -x ; A SAL of 10 -6 is hence identical in meaning to the standard requirement, that a theoretical probability of there being a viable microorganism present should be equal to or less than 1 × 10 -6 .

7. Sterility assurance level (SAL) Figure shows how a population of 1,000,000 (1 × 10 -6 ) microorganisms will be destroyed exponentially during exposure to a given sterilization process

8. sterilization Process monitoring Equipment function tests - proving proper mechanical operation of the sterilizer. • Performance verification tests -showing product exposure for the correct sterilization cycle. • Process validation practices - which indicate bioburden levels, verify the kinetics of microbial inactivation, justify the design of sterilizing treatments and ensure correct pre- and post-handling

9. Equipment function tests Proper design, construction, Installation and operation of the sterilizer Sequence of installation qualification (IQ), operational qualification (OQ) and performance qualification . Installation qualification involves the demonstration and certification the sterilizer. performs reliably under automatic control. Sterilization conditions are capable of being delivered to defined loads.

10. Performance verification tests Physical Sterilization Indicators Chemical Sterilization Indicators Biological Sterilization Indicators Performance verification by quality checks -

11. Physical Sterilization Indicators uses physical parameters for the purpose of ensuring the sterility. Chemical Sterilization Indicators uses various chemicals of which properties change will tell us about sterilization. Biological Sterilization Indicators uses various microorganisms so as to check sterilization.

12. PHYSICAL INDICATORS • Monitoring physical indicators involves observing the gauges or displays on the sterilizer and recording the time, temperature, and pressure associated with each sterilization cycle for each load. • Some sterilizers have recording devices that print out these parameters. • Correct readings do not guaranty sterilization, but incorrect readings can be the first indication of a problem with the sterilization cycle and suggest the load may not be sterile.

13. Physical Sterilization Indicators used for various methods of sterilization Heat Sterilization : . Temperature Record Chart/ Digital monitor and Thermocouples Gaseous Sterilization . Monitoring of Elevated Temperature . Routine Leak Tests (To ensure gas tight seals) . Pressure and Humidity Measurement Radiation Sterilization . Plastic Dosimeter Filtration Sterilization . Bubble Point Pressure Test . Checking Integrity of HEPA Filters (DOP Test)

14. Autoclave Monitors

15. HEPA FILTER INTEGRITY TEST BY DOP ( Dispersed oil particulate) / PAO9 ( Poly Alfa Olefin)

16. Plastic Dosimeter Example: Thymol blue (TB) solutions and Thymol blue Polyvinyl Alcohol (TB-PVA) films have been introduced as Radio chromic dosimeter On irradiation with gamma rays there is bleaching of Thymol Blue dye.

17. CHEMICAL INDICATORS • Chemical indicators use sensitive chemicals to assess critical variables (e.g., time, temperature, or steam saturation) during a sterilization cycle. • They are applied either to the outside or placed on the inside of each instrument unit (e.g., packs, peel pouches, containers, etc … • They do not prove that sterilization has been achieved, but they can provide an early indication of a problem and where in the sterilization process the problem might exist.

18. CHEMICAL STERILIZATION INDICATORS External Chemical Indicator • process indicator - autoclave tape • distinguishes processed from unprocessed medical devices • secures pack • labels pack Internal Chemical Indicator •Inside each package, tray or container •Paper strips or cards •Validates sterilant penetration •Colour change strip or moving front format •Can measure all process parameters (integrators)

19. Class 1 indicators – Referred as process indicators, are intended for use with individual packs or load components to show that the load component has been exposed to a sterilization process . (i.e. to show that a load item has been processed, for example autoclave tape or adhesive labels with an indicator printed onto it).

20. Class 2 indicators - Designed for use in specific test procedures, such as the Bowie–Dick test ( ISO 17665 ) requires that a Bowie–Dick test is performed at the commencement of each day (after a warm-up cycle) in all pre-vacuum steam sterilizers to assess the ability of the sterilizer to penetrate steam into a load of defined resistance. A Bowie–Dick indicator should be placed into an otherwise empty chamber as this is the worst case scenario for steam penetration.

21. Class 3 indicators - Respond only to a single sterilization variable, such as time or temperature. Class 3 indicators are not usually considered useful in processes that have two or more critical variables. Obsolete now

22. Class 4 indicators – Indicators are multi-parameter indicators that will respond to two or more of the variables for the sterilization process for which they are intended. These indicators are designed to be placed with in the load to monitor attainment of sterilization critical variables. These are non toxic Lead Free indicators

23. Class 5 indicators - Designed to integrate all sterilization variables and to be equivalent to, or exceed, the performance of Biological Indicators that are specified in the (ISO 1113) series for BIs. These indicators are designed to be placed within the load to monitor attainment of sterilization critical variables. Also called Pseudo-biological indicators .

24. Class 6 indicators - Also known as cycle verification indicators and Integrators are designed to integrate all sterilization variables with their performance correlated to the actual settings of the sterilization cycle. These indicators are designed to be placed within the load to monitor attainment of sterilization critical variables.

25. Browne’s tubes: Most commonly used chemical indicator for heat process Contains small sealed colored tubes having a reaction mixture and an indicator Expose to high temperature resulting in the change of colour of the indicators.(Red to green)

26. WITTNESS TUBES • Consist of single crystalline substances of known melting point contained in glass tubes Ex: Sulphur(115°C), Succinic anhydride(120°C), Benzoic acid(121°C), etc. • A dye may be included to show more clearly that the crystals have melted. Indicates that a certain temperature has been reached.

27. Heat Sensitive Tape: • It is an adhesive tape used in autoclaving to indicate a specific temperature. • Autoclave tape works by changing color after exposure to temperatures commonly used in sterilization processes, typically 121°C in a steam autoclave. • The tape is similar to masking tape but slightly more adhesive, to allow it to adhere under the hot, moist conditions of the autoclave. • One such tape has diagonal markings containing an ink which changes colour (usually beige to black) upon heating.

28. Royce Sachet : • It's a chemical indicator used for “Ethylene Oxide Sterilization”. • Its a polyethylene sachet containing magnesium chloride, HCl and bromophenol blue indicator • Ethylene oxide penetrates polyethylene bags and reacts with contents- • At a given concentration - time exposure the colour of the mixture changes from yellow to purple due to formation of “Ethylene chlorohydrin”.

29. Chemical Dosimeter • It is the best technique available to measure radiation dose absorbed during sterilization by radiation. • The radio sensitive materials are impregnated in a plastic container and changes colour from yellow to red on exposure to the radiations.

30. Biological Indicators for Sterilization Biological indicators (BIs), as defined by ANSI/AAMI and ISO, are test systems containing viable microorganisms providing a defined resistance to a specific sterilization process. A biological indicator provides information on whether necessary conditions were met to kill a specified number of microorganisms for a given sterilization process, providing a level of confidence in the process.

31. Endospores, or bacterial spores, are the microorganisms primarily used in BIs. They are considered some of the toughest ones to kill. Additionally, bacterial spores are chosen for a specific sterilization process based on their known resistance to that process. For example, Geobacillus stearothermophilus spores demonstrate a high resistance towards steam and vaporized hydrogen peroxide and are therefore used in BIs that monitor these sterilization processes. BIOLOGICAL INDICATORS

32. Types Of Biological Indicators Some BIs contain a single microorganism species, while others contain two species and concentrations of bacterial spores to compare different sterilization processes. There are three primary types of BI indicators 1: Spores On A Carrier 2: Spore Suspension 3: Sealed System Spores

33. 1: Spores On A Carrier In this preparation, spores are placed on a carrier (e.g., a disk or strip). The disks or strips can be paper, glass, plastic, metal, or other materials. BI’s using a carrier are often packaged to maintain the integrity and viability of the inoculated spores on the carrier. Following sterilization, neither the BI carrier nor the BI packaging should be damaged or degraded.

34. 2: Spore Suspension Biological indicators can also be an inoculate spore suspension placed on the product being sterilized or into representative units of the product to be sterilized. A surrogate article that is substantially similar to the product being sterilized can be used if it is not practical to inoculate the actual product. For spore suspensions used in liquid products, the population and D value of the BI spore is critical to determine to evaluate the efficiency of the sterilization process. D- Value or Decimal reduction time • Time in minutes at any defined temperature to destroy 90% viable microorganisms is called D- value

35. 3: Sealed System Spores The third BI option is a sealed system. This sealed system includes the growth medium and the BI microorganisms. The growth medium is either in direct contact with the BI species during the sterilization or is placed in contact with the BI after sterilization. The growth media supports the recovery of any sterilization process-exposed BI microorganisms. Some BI systems contain a growth indicator or sensor in addition to growth media.

36. 4: Rapid readout BI Rapid read out BI with auto readers. Readings can be taken in 4 hrs. It detects the enzyme Beta glucosidase and acid metabolites produced by the indicator organisms by fluorometric method.

37. BIOLOGICAL STERILIZATION INDICATORS Advantages: • Confirms the ability of the sterilization process to kill microbial spores • Large number of spores • Integrate all the parameters of the sterilization process • Most critical test of the sterilization process Disadvantages: The process is time consuming and needs further incubation

38. BIOLOGICAL INDICATOR TESTING PROCEDURE A biological indicator is made up of a carrier material, on which bacterial spores with a defined resistance to the sterilization process have been applied. The carrier material is enclosed within a glassine envelope or a vial. The BI is exposed to the sterilization process and then incubated under defined growth conditions to determine whether any spores survived the process. If no spores survive, none grow and the test is a pass. If growth is detected, the test is a fail. Always follow the manufacturer's instructions for use (IFUs) when using a biological indicator to monitor sterilization processes.

39. PCDs contain both BIs and CIs for a variety of sterilization processes. AAMI standards provide instructions for the assembly of PCDs in hospitals and also recognize the use of commercially prepared, FDA-cleared equivalents. PCDs have two primary components: the barrier component and the sterilization assurance Pr ocess Challenge Device (PCD )

40. Process Challenge Devices for Autoclave

41. 1. Date, sterilizer number and load number 2. Lot number, general contents of load 3. Exposure time, temperature and pressure 4. Operator's name or initials 5. Chemical indicator results 6. Biological indicator results 7. Test results Record Keeping

42. Conclusion Quality Controls are an important tool for use by those responsible for sterilization assurance. Healthcare practitioners must use the best tools available to them when sterilizing medical devices. Despite the high degree of accuracy exhibited by BIs in monitoring sterilization, they should always be used in conjunction with physical measurements and/or CIs to demonstrate the efficacy of a given sterilization process

43. Conclusion . The decision to release the load should then be made by an experienced, knowledgeable person based on the evaluation of all available data from the sterilization process.

44. references Russell, Hugo & Ayliffe’s Principles and Practice of Disinfection, Preservation and Sterilization 5 th edition International Standards Organization (ISO) (2005) ISO/TS 11139. Sterilization of Health Care Products – Vocabulary, ISO, Geneva.

45. thankyou .

46. Process validation practices three components to process validation: selection and validation of the sterilizing cycle; monitoring of cycle; and control of the complete process .