Sterilization methods

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Sterilization methods

  1. 1. STERILIZATIONMETHODS
  2. 2. INFECTION CONTROL IN THE MEDICAL OFFICEInfection control has assumed a greater role in medicine and dentistry than ever before. The Centers for Disease Control (CDC) has issued guidelines for infection control in the the medical, surgical, dental, or podiatric office or clinic. Instrument sterilization is one of the most important parts of office infection control. The cardinal rule of infection control is "Do not disinfect when you can sterilize." The approach is to sterilize all reusable instruments contaminated with blood, or that have penetrated tissue or touched bone (universal sterilization). This is better than to sterilize some instruments and disinfect others and is the safest approach to prevent spreading disease to patients.
  3. 3. STERILIZATION IS A PROCESS INTENDED TO KILLALL MICROORGANISMS AND IS THE HIGHESTLEVEL OF MICROBIAL KILL THAT CAN BEACHIEVED. A process cannot be called a sterilization process unless it has been shown to be capable of killing high numbers of bacterial spores, the most difficult of microorganisms to kill. The CDC views steam under pressure, dry heat, chemical vapor and ethylene oxide gas as appropriate sterilization methods.
  4. 4. To assure effective microbial kill with minimal instrument damage and protection to the staff performing the procedures, several steps must be performed: presoaking, cleaning, corrosion control and lubrication, packaging, sterilization and sterilization monitoring.
  5. 5. PRESOAKINGUsually, material allowed to dry on an instrument ismore difficult to remove. If cleaning is delayed, keep theinstruments wet in a holding solution. This may be amild detergent, or an instrument disinfectant or sterilant.Do not presoak for more than a few hours, as the longerinstruments remain wet, the greater the chances forcorrosion of non-stainless items.Wear heavy utilitygloves when handling contaminated instruments andmixing chemical solutions. Wear protective eyewear, amask and protective clothing to prevent contaminationfrom splashing of the solutions.
  6. 6. CLEANING The CDC and the Food and Drug Administration (FDA) state that"Cleaning is the basic first step of all decontamination. You alwaysneed to clean before you disinfect or sterilize." Patient debris andbody fluids must be removed from the instruments beforesterilization. Debris can insulate microorganisms from the sterilizingagent, preventing direct contact and inactivation.Two approaches toinstrument cleaning are hand-scrubbing and ultrasonic cleaning.Hand-scrubbing is directly contrary to one of the principles ofinfection control (reduce direct contact with contaminated surfacesas much as possible). Handscrubbing of contaminated instrumentscan create spatter and aerosols and increase the chances for aninstrument puncture.When hand-scrubbing, minimize spattering byscrubbing while the instruments are submerged and then rinsethoroughly under tap water and dry. Drying is very important forinstruments that will be sterilized in an unsaturated chemical vaporor in a dry heat sterilizer.
  7. 7. ULTRASONIC CLEANING Ultrasonic cleaning is recommended in place of hand-scrubbing in order to reduce direct staff contact withcontaminated instruments. Presoaked or other instrumentsshould be rinsed and then placed in a cleaning basket andsubmerged in the cleaning solution. For best results,follow the directions from the manufacturer of theultrasonic cleaner. Place the cover on the cleaner andclean for 6 to 10 minutes or until no debris is visible onthe instruments.Hold the cleaning basket of instrumentsunder tap water and rinse thoroughly. Ultrasonic cleanerscannot be considered sterilizers. Thus, the cleanedinstruments are still contaminated. The cleaning solutionshould be drained and discarded at least daily and thecleaner chamber rinsed and disinfected at the end of theday.
  8. 8. CORROSION CONTROL AND LUBRICATION Always dry cleaned instruments to be processed through a dry heat, chemical vapor or ethylene oxide gas sterilizer or packaged in a paper wrap. Drying reduces the chances of corrosion and rupture of the paper wrap. A rust inhibitor can be applied to non-stainless items to be processed through the steam autoclave.
  9. 9. PACKAGING Instruments should be pre-packaged beforeprocessing through a sterilizer so they will beprotected from contamination after sterilization.Use packaging material designed for the methodof sterilization to be used. Avoid thin paper bagsthat allow sharp instruments to protrude.Unwrapping pre packaged instruments at chairside in front of the patient can help build patientconfidence about the cleanliness of the office.
  10. 10. STERILIZATION TIMESterilization fails when the sterilizing agent-- steam, hot air, or chemical vapor--does not contact the processed items for the appropriate length of time. Sterilization requires varying degrees of time, depending on the load, arrangement, packaging material, and temperature as well as the type of sterilizing agent. Follow the manufacturers direction and define the proper sterilizing time by results of routine spore-testing.
  11. 11. STERILIZATION MONITORING Sterilization can be monitored by chemical indicators (color change) but effectiveness cannot. Chemical indicators are strips, tapes and markings on bags and pouches that change color or physical form after exposure to the sterilizing agent. They immediately indicate that the items have been processed through the sterilizer and have been exposed to heat, steam or chemical vapor. Since chemical indicators do not analyze for microbial kill, they should be used in conjunction with, but never as a replacement for spore-testing, which provides the main guarantee of sterilization.
  12. 12. BIOLOGICAL INDICATORS Biological indicators are the ultimate criteria for monitoring sterilization. The CDC states the proper functioning of sterilization cycles should be verified by the periodic use (at least weekly) of biologic indicators (i.e., spore tests). OSHA recommends following CDC guidelines for standard sterilization procedures.
  13. 13. Proper spore-testing in the medical, surgical, dental, orpodiatric office or clinic involves placing the appropriatetype of biological indicator (spore test) inside a normalinstrument pack, bag, or tray. Biological indicatorsoperate on the premise that destruction of heat-resistantspores implies destruction of viruses and bacteria, whichare more easily inactivated. The biological indicator isincluded in a sterilization load and subjected to the cycle.It is then incubated in a nutrient medium and evaluated.Itis the responsibility of each themedical, surgical, dental, or podiatric office or clinic toassure their staff and patients that products at point-of-use are sterile. Appropriate records should be kept todocument sterilization verification.
  14. 14. References(1.) Department of Labor, Occupational Safety and Health Administration. 29CFR Part 1910.1030, Occupational exposure to bloodborne pathogens; final rule. Fed Reg 1991,56:64004-182.(2.) Infection control guidelines. Denver: Office Sterilization and Asepsis Procedures Research Foundation; 1992.(3.) Office Sterilization and Asepsis Procedures Research Foundation. Infection control guidelines. Denver; 1991.(4.) Centers for Disease Control. Recommended Infection- Control Practices. MMWR 1993; 42:1-10.
  15. 15. A. METHODS OF STERILIZATION
  16. 16. 1. PHYSICAL METHODSSteam ThermalDefinition -- a self-locking apparatus for the sterilization of material by means of steam under pressure. Settings for general wrapped items: Temp. - 250oF Pressure - Time -- 30 min Setting -- Fast Exhaust & Dry
  17. 17.  Settings for bottled solutions: Always vent bottles to avoid bursting! Temp. - 250oF Pressure - 20 PSI Time -- 30 min Setting -- Slow Exhaust Setting for "Flashing" an unwrapped instrument: Temp. - 270oF Pressure Time -- 4-7 Min Setting -- Fast Exhaust Notes -- The above are general steam autoclave settings. Different models may operate with varying settings. Always refer to the appliance literature before operating a new piece of equipment.Radiation Use on materials that cannot be sterilized by heat or chemicals Radiant energy destroys microorganismsFiltration -- is a method utilizing filters capable of screening out microorganisms
  18. 18. 2. CHEMICAL METHODS
  19. 19.  Ethylene Oxide Gas Colorless gas at room temperature Odor similar to ether Very toxic and irritating to skin and mucous membranes Microorganism destruction is caused by a chemical reaction Materials sterilized need to be aerated in well ventilated room or placed in an aerator. Length of time required for aeration depends on items sterilized. Effective sterilization is dependent on concentration of gas, exposure time, temperature, and relative humidity Hazardous chemical, use great care
  20. 20.  Cold Sterilization Instruments should be completely dry before soaking to prevent dilution Instrument soaking solution - 10-20 minute emersion only disinfects Incomplete destruction of spores, unless soak is for 10 hours Examples: Instrument Germicide (Phenol and Ethyl alcohol), CidexTM (Glutaraldehyde) Most require thorough rinsing before using instrument Contact time required varies with product used
  21. 21. B. STERILIZATION SHELF LIFE OFPACKAGED SUPPLIES
  22. 22. 2. TWO (2) PACKAGING METHODS ARE STERILEFOR UP TO SIX (6) MONTHS: MonarchR Instrument Canisters -- Special box system with single use filters for use in steam autoclaves Sterility Maintenance Covers -- Sealable plastic covers to place over freshly autoclaved and cooled packs to extend shelf life by diminishing air penetration
  23. 23. 1. THE FOLLOWING WRAPPED ITEMS, IFCAREFULLY MAINTAINED, ARE STERILEFOR UP TO ONE (1) MONTH: Double cloth wrapped instruments Double paper wrapped instruments Inexpensive peel pouches for gauze sponges NalgeneR saline bottles
  24. 24. 3. HEAT SEALED PACKAGES COMMERCIALLY PREPARED IN TUBE OR PEEL POUCH FORM MAY BE CONSIDERED STERILE FOR UP TO ONE (1) YEAR.C. Sterility Check List
  25. 25. BEFORE ASSUMING A PACK IS STERILE, ALWAYSEVALUATE THE FOLLOWING BEFORE OPENING THEPACK:Expiration or sterilization dateIndicator color changeGeneral condition of wrapper and how it had been storedAlways check for holes or moisture damage

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