Gasplasma Sterilization


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Gas plasma Sterilization

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Gasplasma Sterilization

  2. 2. ADVANCES IN STERILIZATION• Sterilization, as a specific discipline, has been with us for approximately 120 years, since the invention of the steam autoclave by Charles Chamberland in 1879.1 Since that time, we have seen progressive refinement in steam sterilizers: from the early, manually operated equipment to modern microprocessor-controlled, automatic machines. Although the efficiency, reliability, and performance monitoring of modern equipment is continually improving, the fundamental process remains essentially the same.DR.T.V.RAO MD 2
  3. 3. GAS PLASMA• Gas Plasma (vaporized hydrogen peroxide) is a relatively new option that can provide low heat sterility cycles with none of the off-gassing concerns present with EtO. Gas Plasma (VHP) sterilization has, until now, been exclusively used by large manufacturers as the end line process for in-house sterilization.DR.T.V.RAO MD 3
  4. 4. WHO FOUND IT? • Who Found It? First discovered by Sir William Crookes, in 1879 But it wasn‟t called „plasma‟ until 1928, when Irving Langmuir coined the termDR.T.V.RAO MD 4
  5. 5. PLASMA STERILIZATION• A plasma is a quasi-neutral collection of electrons, positive ions, and neutrals capable of collective behavior• Positive ions = free radicals• Plasma sterilization operates synergistically via three mechanisms: • Free radicals interactions • UV/VUV radioactive effects • Volatilization• Dead microorganisms = sterilization DR.T.V.RAO MD 5
  6. 6. PLASMA STERILIZATION MECHANICS: IR (NUCLEIC ACID VIEW), UV RADIATION• UV/VUV radiation causes • formation of thymine dimers in DNA, inhibiting bacterial replication. • Base damage • Strand breaksDR.T.V.RAO MD 6
  7. 7. BEGINNING OF GAS PLASMA• Gas plasma sterilization technology based of Plasma was patented in 1987, and marketed in U S 1993.DR.T.V.RAO MD 7
  8. 8. CURRENT STERILIZATION MEANS: PLASMAS?• Yes.• Plasmas are currently employed in many industries to accomplish both highly effective, and delicate sterilization.• Not future technology! Plasmas are used today!• But, how do they work?
  9. 9. WHAT IS GAS PLASMA• Plasma is a fourth state of matter which is distinguishable from liquid, solid, or gas. In nature, plasma is widespread in outer space.• Gas plasma generated in an enclosed chamber under deep vacuum using Radio frequency or Microwave emery to excite gas molecules are produced charged particlesDR.T.V.RAO MD 9
  10. 10. HOW GAS PLASMA WORKS.• Many particles are in the form of free radicals• A free radical is an Atom with an unpaired electron and is a highly reactive species• The mechanism of action of this device is the production of free radicals within a plasma field that are capable of interacting with essential cell components, ie is enzymes and nucleic acids. And thereby disrupt the metabolism of microorganisms.DR.T.V.RAO MD 10
  11. 11. BASIC MECHANISMS OF PLASMA STERILIZATION• A-Destruction by UV irradiation of the genetic material of the microorganism; this is a statistical process requiring a sufficient number of lesions of the DNA strands.• B- Erosion of the microorganism, atom by atom, through intrinsic photo desorption Photon-induced desorption results from UV photons breaking chemical bonds in th microorganism material and leading to the formation of volatile compounds from atoms intrinsic to the microorganism. The volatile by-products of this nonequilibrium chemistry are small molecules (e.g., CO and CHx)DR.T.V.RAO MD 11
  12. 12. BASIC MECHANISMS OF PLASMA STERILIZATION• Erosion of the microorganism, atom by atom, through etching. Etching stems from the adsorption of reactive species from the plasma (glow or afterglow) on the microorganism with which they subsequently undergo chemical reactions to form volatile compounds (spontaneous etching). The reactive species can be atomic and molecular radicals, for example, O and O3, respectively, and excited molecules in a metastable state, for example, the O2 singlet state all spores are ultimately inactivated by UV photon irradiation of their DNA materialDR.T.V.RAO MD 12
  13. 13. IDENTIFIED ADVANTAGES• Materials and device compatibility• Rapid turnaround times• In-house control of the sterilization process• Lower inventory requirements.DR.T.V.RAO MD 13
  14. 14. BENEFICIAL FOR STERILIZING TEMPERATURE- SENSITIVE POLYMERIC MATERIALS• The advantages of gas plasma sterilization include its ability to provide safe, non toxic, dry, low- temperature sterilization in about one hour. By- products of plasma sterilization are primarily water and oxygen. Because these by-products are harmless, there is no need for aeration or environmental hazard concerns. DR.T.V.RAO MD 14
  15. 15. STEPS IN PLASMA STERILIZATION• The Vacuum Phase• The chamber is evacuated, reducing internal pressure in preparation for the subsequent reaction.• The Injection Phase• A measured amount of liquid peroxide is injected into the chamber, evaporating the aqueous hydrogen peroxide solution and dispersing it into the chamber, where it kills bacteria on any surface it can reach. DR.T.V.RAO MD 15
  16. 16. THE DIFFUSION PHASE• The hydrogen peroxide vapour permeates the chamber, exposing all load surfaces to the sterilant and rapidly sterilizes devices and materials without leaving any toxic residues. At the completion of this phase, the chamber pressure is reduced and the plasma discharge is initiated.DR.T.V.RAO MD 16
  17. 17. THE PLASMA PHASEAn electromagnetic field is created in which the hydrogenperoxide vapour breaks apart, producing a low-temperatureplasma cloud that contains ultraviolet light and free radicals.Following the reaction, the activated components lose their highenergy and recombine to form oxygen and water.Phases 1, 2, and 3 are then run a second time for added efficacy.This built-in reprocessing assures optimal sterilization for eventhe most difficult-to-sterilize devices. DR.T.V.RAO MD 17
  18. 18. THE VENT PHASE The chamber is vented to equalize the pressure enabling the chamber door to be opened. There is no need for aeration or cool-down. Devices are ready for immediate use.DR.T.V.RAO MD 18
  20. 20. PLASMA STERILIZATIONMECHANICS: IR (CELLULAR VIEW)• IR impacts the cell, three outcomes can result.
  21. 21. ADVANTAGES OF PLASMA STERILIZATION• Low-Temperature Hydrogen Peroxide Gas Plasma (LTHPGP) has a number of advantages compared to established sterilization technologies. These include a short (one to four hours) sterilization cycle, low temperature and humidity, no aeration requirement, no toxic chemical residues or environmental impact, and broad compatibility with mat erials.DR.T.V.RAO MD 21
  22. 22. HYDROGEN PEROXIDE GAS PLASMA.• The Sterrad system offers a short cycle (averaging 75 minutes), low temperature and humidity, no aeration requirement, no chemical residues, negligible environmental impact, and wide compatibility with materials. Its drawback is an inability to process liquids, powders, or strong absorbers (e.g., cellulosics).DR.T.V.RAO MD 22
  23. 23. THE BIOLOGICAL INDICATOR FOR QUALITY CONTROL• The Biological indicator used with system is Bacillus atrophaeus spores. And Bacillus sterothermophilisDR.T.V.RAO MD 23
  24. 24. IMPROVEMENT TO NEW TECHNOLOGY• The newer version of unit, which employs a new vaporization system that removes most of the water from hydrogen peroxide, has a cycle time from 28- 38 minutes.DR.T.V.RAO MD 24
  25. 25. MODE OF ACTION IN GAS PLASMA USAGE The process inactivates microorganisms primarily by the combined use of hydrogen peroxide gas and the generation of free radicals ( hydroxyl and hydroproxyl free radicals ) during the plasma phase of the cycle.DR.T.V.RAO MD 25
  26. 26. USES OF GAS PLASMA IN HOSPITALS• Materials and devices that cannot tolerate high temperatures and humidity such as some plastics, electrical devices, and corrosion- susceptible metal alloys, can be sterilized by hydrogen peroxide• This method proved compatible with most (>95%) medical devices and materials tested.DR.T.V.RAO MD 26
  28. 28. GAS PLASMA WORK STATION• Medical instrumentation can be sterilized through a hydrogen peroxide gas plasma process with the Sterrad 100 system (Advanced Sterilization Products). Photo: Advanced Sterilization Products DR.T.V.RAO MD 28
  29. 29. DISADVANTAGES OF PLASMA STERILIZATION• Weak penetrating power of the plasma species. Complications arise in: • Presence of organic residue • Packaging material • Complex geometries • Bulk sterilization of many devices• Solutions: Introduce preferentially targeting UV/VUV radiation of proper wavelength DR.T.V.RAO MD 29
  30. 30. DISADVANTAGES• The disadvantages of gas plasma sterilization are that it may not penetrate well, especially in channels or devices designed with long lumens. In addition, the gas plasma sterilization method may corrode some materials and cannot be used on paper, cellulose or linen. An additional drawback to plasma sterilizers is their small chamber.DR.T.V.RAO MD 30
  31. 31. ACCEPTABLE TECHNOLOGY• According to experts, only a few disadvantages associated with gas plasma sterilization exist. These include the inability to process liquids, powders, or strong absorbers (cellulosics), and some lumen restrictions. Also, gas plasma sterilization is not recommended for liquids and other devices that can be damaged physically or changed by exposure to low pressure.DR.T.V.RAO MD 31
  32. 32. STERRAD TECHNOLOGY• In 1993, the STERRAD Technology received clearance and was introduced into the United States. It is now available in more than 60 countries throughout the world with over 6,000 units sold, making it the worlds fastest growing sterilization technology.DR.T.V.RAO MD 32
  33. 33. STERRAD 100• The STERRAD 100 sterilization system (Johnson & Johnson Medical Ltd) uses low temperature hydrogen peroxide gas plasma for sterilization of heat labile equipment.DR.T.V.RAO MD 33
  34. 34. SHORT COMING OF GAS PLASMA STERILIZATION • An important shortcoming of plasma sterilization is its dependence on the actual “thickness” of the microorganisms to be inactivated since the UV photons need to reach the DNA. Any material covering the microorganisms, including packaging, will slow down the process.DR.T.V.RAO MD 34
  35. 35. GROWING PROBLEM WITH PRIONS• Prion diseases, or proteinaceous infectious particle only agents, are able to induce abnormal folding of normal cellular prion proteins in the brain and can develop into neurodegenerative disorders including Gerstmann-Straussler- Scheinker Syndrome, fatal familial insomnia and Creutzfeldt-Jakob Disease (CJD) in humans. Such prion diseases can have long asymptomatic incubation periods but will result in fatality in all cases. Unlike infectious agents in other difficult-to-treat infectious diseases, prions exhibit an unusually high level of resistance to common sterilization methods and disinfection methods, including steam, and pose a threat to infection prevention in healthcare facilities.DR.T.V.RAO MD 35
  36. 36. STERRAD TECHNOLOGY IS SAFE IN DEALING IN CONTAMINATION WITH PRIONS• The effectiveness of low- temperature STERRAD® technology against the prion threat confirmed that is possible to eliminate these deadly pathogens while helping to preserve the integrity of medical devices, including heat sensitive surgical instrumentsDR.T.V.RAO MD 36