Importance of sterilization,
In health care setting it is important;
In health care setting it is important;
-
To render articles and environment safe from the risk of transmitting infections.
- Pathogens on hands & environment are removed or destroyed by ,
–
high standard of cleanliness
–
drying, washing, good ventilation and sun light.
● High risk
procedures
o
Require absolute sterility
–
Surgery
–
preparation
•
of culture media
•
Iv fluids and other injectable drugs
–
Types of research work
● Sterilization: Complete removal of all microorganisms
●
Disinfection:
- Destruction of microorganisms
- Excluding bacterial spores.
- Does not necessarily kill all microorganism
- Reduce them to a level, which is not harmful.
● Decontamination:
Procedure that makes an inanimate
object safe for patient care
eg. Thermometer, stethoscope
● Antisepsis:
The same procedure applied to living
things
● Methods of sterilization,
1) Heat:
a) Dry heat:
o
Flaming
–
bacteriological loops
–
microscopic slides
–
metal instruments used in labs
o
Incineration - burning
–
discarded dressings
–
needles & syringes
–
human tissues etc….
o
Hot air oven: used in the laboratories to
sterilize glassware.
–
160ºc for 1 - 1 1/2 hours
b) Moist heat:
More
penetration and more lethal to
microorganisms
Pasteurization
Boiling
Autoclaving - Autoclaves
o
simplest form - pressure cooker
o
Increased pressure water boils at very high pressure
–
15 lbs
/sq.inch water boils at 121ºC X15 min
–
20
lbs/sq.inch water boils at 126ºC X10 min
–
30 lbs
/sq.inch water boils at 134ºc X 3 min.
•
generates steam at high temperatures
•
good penetration into articles
o
used for sterilizing
–
theater
equipment and wrapped instruments
–
gloves,
gowns, etc…
–
contaminated
equipment
● Monitoring of autoclaves:
o
Physical monitoring
o
Autoclave indicator tapes
o
Bowie Dick tape
o
Biological tests
2) Radiation
3) Filtration
4) Chemicals
o
Liquids and gases are used
o
An article should be thoroughly cleaned with
soap and water or any detergent before applying chemicals
- Alcohol, aldehydes, halogens, diguanides,phenolics, quaternary ammonium compounds
- Peracetic acid, heavy metals, dyes, oxidizing agnts
- Peracetic acid
- Soaps, gases, ethylene oxide, formaldehyde, gas plasma
● Factors determining
effectiveness of chemical disinfection:
o Selection of appropriate agent
–
Blood
spill - phenolic X, Strong hypochloritea
o Concentration
o Prior cleaning
–
presence
of inactivating organic matter
o Time of exposure
o Correct pH
o Temperature & volume
o Container
● Selection of disinfectant level
o
Critical instruments
– Come
into contact with blood, body fluids & penetrate mucous membranes
–
Sterilization
recommended
– Rarely
high level disinfection may be OK
o
Semi
critical
–
Make
contact with mucous membranes
–
Does not
penetrate
–
High
level disinfection
o
Non
critical
–
Touch
intact skin
–
Cleaning
& low level disinfection
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