Sterilization p pdesign_final
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    Sterilization p pdesign_final Sterilization p pdesign_final Presentation Transcript

    • SterilizationBMT_3351 Asepsis: Sterilization and Disinfection
    • SterilizationBMT_3352 Asepsis • It is keeping medical instruments free from microorganisms • This is accomplished by: I. Sterilization II. Disinfection
    • 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.
    • 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
    • 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
    • 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
    • I. Sterilization - Process
    • 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
    • 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.
    • SterilizationBMT_33510 1.HEAT STERILIZATION
    • 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
    • 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
    • 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.
    • 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.
    • 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
    • SterilizationBMT_33516 2. CHEMICAL STERILIZATION
    • 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, )
    • 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.
    • 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).
    • 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.
    • SterilizationBMT_33521 3. RADIATION STERILIZATION
    • 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.
    • 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
    • SterilizationBMT_33524 II. DISINFECTION
    • 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.
    • SterilizationBMT_33526 1. Heat Disinfection • It is accomplished by boiling water at atmospheric pressure for at least 5 min’s
    • 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
    • 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
    • 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.
    • SterilizationBMT_33530 Disinfection and Sterilization - New methods
    • 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
    • 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)
    • 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).
    • SterilizationBMT_33534 2. Surfacine • Surface disinfectants such as phenols • Advantages – Effective in significantly reducing microbial contamination – Cost-effective – Have long-term residual activity
    • 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
    • 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
    • SterilizationBMT_33537 5. Hydrogen Peroxide Plasma • A New Low-Temperature Sterilization Technique. • Can be used for temperature-sensitive equipment.
    • 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
    • SterilizationBMT_33539 Sterilization & Disinfection End