Sterilization p pdesign_final


Published on

Published in: Technology, Business
  • Be the first to comment

Sterilization p pdesign_final

  1. 1. SterilizationBMT_3351 Asepsis: Sterilization and Disinfection
  2. 2. SterilizationBMT_3352 Asepsis • It is keeping medical instruments free from microorganisms • This is accomplished by: I. Sterilization II. Disinfection
  3. 3. SterilizationBMT_3353 I. Sterilization • It is one of the basic steps in surface asepsis. • Definition: Sterilization refers to the use of different procedures to destroy all forms of microorganisms including bacterial spores.
  4. 4. SterilizationBMT_3354 What to sterilize? • It is mandatory to sterilize : – all instruments that penetrate soft tissues and bone. – Instruments that are not intended to penetrate the tissues, but that may come into contact with oral tissues. • If the sterilization procedure may damage the instruments, then, sterilization can be replaced by Disinfection procedure
  5. 5. SterilizationBMT_3355 II. Disinfection • It a is less lethal process than sterilization. • Definition: It is a procedure intended to reduce microorganisms as far as possible (but not bacterial spores). • Thus, disinfection can never replace sterilization
  6. 6. SterilizationBMT_3356 Which procedure to use? Category Items in each category Procedure Critical Items that: (1) enter the tissue; (2) Enter vascular system; (3) through which blood flows Sterilization Semi-critical Items that: (1) touch mucous membranes; (2) touch non-intact skin (e.g. endoscopes, respiratory therapy equipment, and diaphragms) High level disinfection Non-critical Items such as bedpans, blood pressure cuffs, and bedside tables Low level disinfection
  7. 7. I. Sterilization - Process
  8. 8. SterilizationBMT_3358 Sterilization – instrument Packing • Often instruments are packed for sterilization to be stored and handled without being contaminated. • Packing depend on the intended shelf life after sterilization. • The available packing options are: – Textile has shelf life of 1 month – Paper has shelf life of 1 – 6 months – Nylon, glass, and metal have shelf life of 1 year if tightly closed
  9. 9. SterilizationBMT_3359 Sterilization Principles • There are 3 different sterilization principles: 1. Heat sterilization 2. Chemical sterilization 3. Radiation sterilization • Each principles is discussed in the following sections.
  10. 10. SterilizationBMT_33510 1.HEAT STERILIZATION
  11. 11. SterilizationBMT_33511 1. Heat Sterilization • Advantages: It is the simplest, most effective and inexpensive method. • There are 2 procedures depending on the tolerance of the material used: a) Steam sterilization (Autoclaving) b) Dry heat sterilization
  12. 12. SterilizationBMT_33512 1.a. Heat – Steam Sterilization • Use saturated steam above 100º C on packed items. • Objects occupy 4/5 of autoclave volume to facilitate circulation. • Process is divided into 3 periods as follows: – Pre-vacuum period: air is withdrawn from device – Sterilizing period: steam is introduced under pressure to specific temperatures & times. – Post-vacuum: steam is withdrawn to dry autoclave Table shows samples of time-temperature relationships for steam sterilization
  13. 13. SterilizationBMT_33513 Steam Sterilization Advantages & Disadvantages • Advantages: – good penetration – maintains integrity of liquids (e.g. Lubricants) due to the 100% humidity within the chamber. • Disadvantages: – Non stainless steel metal items corrode – may damage plastic and rubber items – sharp instruments get dulled.
  14. 14. SterilizationBMT_33514 1.b. Dry-Heat Sterilization • Involves heating at atmospheric pressure and often use a fan to obtain uniform temperature by circulation. • Heat at 180º for half hour , 170º for 1 hr., or 160º C for 2 hrs. • Times are the periods during which object is maintained at the respective temp.
  15. 15. SterilizationBMT_33515 Dry-Heat Sterilization Disadvantages • Disadvantages: – Less reliable than autoclaving – Large temp difference may arise within device. – sharp instruments get dulled – Many materials do nottolerate dry heat
  16. 16. SterilizationBMT_33516 2. CHEMICAL STERILIZATION
  17. 17. SterilizationBMT_33517 2. Chemical Sterilization - Types • The chemical compounds used can be: a) Gas Sterilization b) Liquid Sterilization • Generally, chemical sterilization procedures have the disadvantages of presenting health hazards to users (e.g. poisonous, flammable, )
  18. 18. SterilizationBMT_33518 2.a) Gas Sterilization • The gas used in this procedure is ethylene oxide. • Procedure: – Keep objects in constant atmospheric humidity. – Heat to temperatures between 30º and 60º C. – maintain for a period of 10 hrs. – Residual ethylene oxide must be ventilated • Formalin gas autoclaves have been developed for sterilizing endoscopes and ansthetic apparatus.
  19. 19. SterilizationBMT_33519 Gas Sterilization – Disadvantages • Ethylene oxide (& formalin) autoclaves have the following disadvantages: – Difficult to operate – Unsuitable for hospitals but used in industry (e.g. for sterilizing disposable materials that can not tolerate high temperatures).
  20. 20. SterilizationBMT_33520 2.b) Liquid Sterilization • Can be performed with buffered glutaric aldehyde. • Procedure: – Immerse object in liquid for several hours. – Rinse with sterile water after end of procedure.
  21. 21. SterilizationBMT_33521 3. RADIATION STERILIZATION
  22. 22. SterilizationBMT_33522 3. Radiation Sterilization • Provides effective way of sterilization when used in high doses. • Gamma radiation (from 60 Co). • Procedure: – Objects on belt conveyer – Expose objects to 25 to 30 kGy for about 24 hrs.
  23. 23. SterilizationBMT_33523 Radiation Sterilization Advantages and Disadvantages • Advantages: – Clean process – Dry process – Ensures full exposure of object from all directions • Disadvantages: – Posses threat to humans (radiation) – Lengthy process – Requires very qualified personnel
  24. 24. SterilizationBMT_33524 II. DISINFECTION
  25. 25. SterilizationBMT_33525 Disinfection - Types • As mentioned before, disinfection can not kill all microorganisms but only reduce its number. • Disinfection can be accomplished with: 1. Heat disinfection 2. Chemical disinfection • Object that can be disinfected are bedpans, patient skin before operation and surgeon hands before putting gloves.
  26. 26. SterilizationBMT_33526 1. Heat Disinfection • It is accomplished by boiling water at atmospheric pressure for at least 5 min’s
  27. 27. SterilizationBMT_33527 2. Chemical disinfection • Number of different agents are used according to tolerance of objects and infectious agents. – Using phenol with cleaning component destroy the membrane of microorganisms. – Using 70% alcohol for skin which denatures proteins of microorganisms. – Use soap containing hexachlorophene for hands. – In case of hepatitis use 5% solution of chloramines or heat disinfection
  28. 28. SterilizationBMT_33528 Asepsis Sterilization Disinfection Heat RadiationChemical Heat Chemical Steam Dry heat Gas Liquid Gamma Boiling water Phenol Heat or chloramines solution Hexachlorophene 70%AlcoholEthylene oxide Formalin Glutaric Aldehyde Asepsis – Summary
  29. 29. SterilizationBMT_33529 Conclusion • In summary: – Sterilization and disinfection are costly and time consuming process – However, it is an essential in all health care facilities to avoid spread of diseases. – It depends on the ehtics of the instrument users. – Users should keep in mind that contaminated instrument present risk to patient as well as the user himself.
  30. 30. SterilizationBMT_33530 Disinfection and Sterilization - New methods
  31. 31. SterilizationBMT_33531 Table 1. New methods in disinfection and sterilization Process Agent Regulatory agency action Disinfection Ortho-phthalaldehyde (Cidex OPA) FDA cleared, October 1999 Antimicrobial coating (Surfacine) Not FDA/EPA cleared Superoxidized water (Sterilox) Not FDA/EPA cleared Sterilization Liquid sterilization process (Endoclens) Not FDA cleared Rapid readout ethylene oxide biological indicator (Attest) Not FDA cleared New plasma sterilizer (Sterrad 50) FDA cleared, January 1999
  32. 32. SterilizationBMT_33532 1. Ortho-Phth-alaldehyde (OPA) • Chemical Sterilizaer • Adventages: – not eye and nasal passages irritant – has excellent stability over a wide range of pH (3 to 9) – has a barely perceptible odor – Like glutaric aldehyde, it has excellent material compatibility • Disadvantage: – It stains proteins gray (including unprotected skin)
  33. 33. SterilizationBMT_33533 OPA vs. Glutaric Aldehyde Table 2. Activity of glutaraldehyde and ortho-phthalaldehyde against Mycobacterium bovis Disinfectant Time for 6-log10 reductiona 1.5% glutaraldehyde 28-36 minutes 2.5% glutaraldehyde 14-18 minutes 0.21% ortho-phthalaldehyde 4.8-6.3 minutes a Range of values from two different laboratories (4).
  34. 34. SterilizationBMT_33534 2. Surfacine • Surface disinfectants such as phenols • Advantages – Effective in significantly reducing microbial contamination – Cost-effective – Have long-term residual activity
  35. 35. SterilizationBMT_33535 3. Superoxidized Water • Based on the concept of electrolyzing saline. • Advantages: – Cheap – The end product (water) is not damaging to the environment • Available in the United Kingdom; Sterilox
  36. 36. SterilizationBMT_33536 4. Endoclens • A New rapid automated liquid Chemical Sterilization System. • The sterilant is produced, as needed, by automatic mixing of solutions of hydrogen peroxide and formic acid. • Advantages: – automatic cleaning process – capability to process two flexible scopes at same time – automated channel blockage and leak detection – filter water rinsing and scope drying after sterilization – hard-copy documentation of key process parameters – user-friendly machine interface – total cycle time less than 30 minutes
  37. 37. SterilizationBMT_33537 5. Hydrogen Peroxide Plasma • A New Low-Temperature Sterilization Technique. • Can be used for temperature-sensitive equipment.
  38. 38. SterilizationBMT_33538 6. low-temperature plasma • Technique for decontaminating thermolabile products without the severe drawbacks of gas sterilization methods. • Advantages: – Alternative to steam sterilization for sterilizing easily corroding products or electronic instruments – Takes less time. • However, Steam sterilization proved to be the cheapest method of sterilizing
  39. 39. SterilizationBMT_33539 Sterilization & Disinfection End