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Sterilization & Disinfection

The document outlines sterilization and disinfection methods in general surgery, defining sterilization as the removal of all viable microorganisms and disinfection as the reduction of viable microorganisms. Various sterilization methods include autoclaves, hot ovens, ethylene oxide, low temperature steam with formaldehyde, irradiation, and sporicidal chemicals, each with specific applications and limitations. Disinfection methods include low temperature steam, boiling water, and chemical disinfectants, highlighting their effectiveness against different types of microorganisms.

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Kaung Khant
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6 views3 pages

Sterilization & Disinfection

The document outlines sterilization and disinfection methods in general surgery, defining sterilization as the removal of all viable microorganisms and disinfection as the reduction of viable microorganisms. Various sterilization methods include autoclaves, hot ovens, ethylene oxide, low temperature steam with formaldehyde, irradiation, and sporicidal chemicals, each with specific applications and limitations. Disinfection methods include low temperature steam, boiling water, and chemical disinfectants, highlighting their effectiveness against different types of microorganisms.

Uploaded by

Kaung Khant
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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General Surgery Eindra

STERILIZATION
DEFINITION

 It is a method of removal or destruction of all viable microorganisms including spores & viruses

METHODS OF STERTILIZATION
1. Autoclaves
 Mechanism
 Steam under pressure has a temp: >100C
 Vacuum has to be created
 Need to have steam in direct contact with material
 Need to autoclave for 3min at 134C OR for 15min at 121C
 Can check performance by color changes on indicator tape
 Effective against viruses & spore-forming bacteria
 Suitable
 All metal surgical instruments, Gloves, Gowns & drainage tubes, etc
 Unsuitable
 Heat sensitive objects

2. Hot ovens
 Mechanism
 Requires temp: of 160C x 2hrs OR 180C x 30min
 Suitable
 Ointments, grease & airtight containers & also for surgical blades
 Unsuitable
 Rubber, plastics & fluids
 Less efficient than autoclaves

3. Ethylene Oxide
 Mechanism
 Highly penetrative & active against bacteria, spores & viruses
 Suitable
 Heat-sensitive items ( eg: syringes, ryle’s tube & catheter ) )
 Unsuitable
 Also flammable, toxic & expensive
 Leaves toxic residues on sterilized items
 Instruments need to be sotred for prolonged period before use

4. Low temperature steam & formaldehyde


 Mechanism
 Sterilized by combination of dried saturated steam & formaldehyde
 Sterilization is achieved at a low temperature ( 73C )
 Suitable
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General Surgery Eindra

 Heat-sensitive & plastic materials


 Unsuitable
 Sealed oily items or those with retained air
 Hypersensitivity to some users

5. Irridiation
 Mechanism
 Sterilized by using gamma rays or accelerated electrons ( Dose > 25kGy )
 Suitable
 For sterilization of large batches of similar products like plastic syringes , IV
cannulas & catheters
 Industrial uses rather than hospital uses

6. Sporicidal chemicals
 Mechanism
 2% Glutaldehyde solution ( can sterilize if used for long period )
 Suitable
 Inexpensive & suitable for heat sensitive items
 Most bacteria & viruses are killed within 10 min but spores can survive several
hours
 Unsuitable
 Toxic & irritant

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General Surgery Eindra

DISINFECTION

DEFINITION
 It is a method of reducing number of viable microorganisms excluding viruses & bacterial spores

METHODS OF DISINFECTION

1. Low Temperature Steam


 Mechanism
 Usually achieved with a dry saturated stea at 73C for a period of 20min
 Most bacteria & some viruses are killed by exposure to moist heat
 Suitable
 For sterilizing instruments with a lumen
 Also used for disinfection of heavily contaminated instruments before
sterilization
 Unsuitable
 For heat-sensitive items

2. Boiling water
 Achieved with boiling water 100C x 15 min at normal pressure

3. Chemical disinfectants
 Mechanism
 By using disinfectants such as Glutaldehyde 2% solution , phenol, hypochloride,
bleaching powder
 Different organisms vary in their sensitivity
Gram +  highly sensitive
Gram -  relatively resistant
Clostridium & Mycobacterium  very resistant
Slow virus  highly resistant
 Suitable
 For heat sensitive items but it is less effective than heat
 Useful for flexible endoscope

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