1. Sterilization Methods1

3. Sterilization is a process that kills all micro-organisms such as fungi, bacteria, viruses and spores that are present on a surface.
The aim of sterilization is to destroy
all forms of microbial life

4. Methods of Sterilization
Heat sterilization
Moist heat
Dry heat
Chemical sterilization
Liquid
Gas

5. Moist Heat
The quickest most effective method of sterilization is the Steam Autoclave
Autoclaving will inactivate all fungi, bacteria, viruses and also bacterial spores and most prions (Prions cause “mad cow” disease)

6. Moist Heat
Autoclaves use steam heated to 121–134 °C (250–273 °F) with a holding time of at least 15 minutes at 121 °C (250 °F)
Additional sterilizing time is required for liquids and instruments packed in layers of cloth, as they may take longer to reach the required temperature

7. What is a Steam Autoclave?
An autoclave has a heavy metal steel chamber surrounded by a jacket with a space between
Autoclaves have indicators that record or display information (temperature & pressure)
A vacuum in the chamber removes air which could become trapped and cause cold areas which could lower the temperature of the steam and prevent steam penetration

8. What is a Steam Autoclave?
An autoclave works by steam under pressure which creates a high temperature
Pressure forces the steam through everything which needs to be sterilized
A vacuum after sterilization dries the contents
Filtered air is reintroduced to equalize pressure before opening the door

9. Steam Autoclaves
Indicator tape is placed on packages prior to autoclaving. A chemical in the tape will change color when the appropriate conditions have been met. Some types of packaging have built-in indicators on them.
Biological indicators and Bowie Dick tests can also be used to independently confirm autoclave performance.

11. Steam Autoclaves
Indicators should be placed in the most difficult places for the steam to reach to ensure that steam actually penetrates
For effective sterilization, steam needs to penetrate the autoclave load uniformly, so an autoclave must not be overcrowded, and the lids of bottles and containers must be left ajar

12. All instruments must be double wrapped in linen or special paper or placed in a special metal box equipped with a filter before sterilization

13. Steam Autoclave

15. Steam Autoclave on FEH

16. Flash Autoclave
Flash sterilization was designed for OR for the immediate use of a forgotten or unanticipated instrument or for one that was accidentally dropped on the floor
Flash Autoclaves use steam heated to 134 °C (273 °F) for 3 minutes
Instruments are autoclaved unwrapped for a shorter period of time.

17. Flash Autoclave on FEH

18. Dry Heat Sterilization
Was used in Ancient Rome to sterilize instruments by means of a flame. During the Middle ages, it mostly disappeared resulting in disabilities and death following surgical procedures
More effective method is the Hot Air Oven

19. Hot Air Oven
Electrical device which uses dry heat to sterilize articles
Operated from 50 to 300 °C (122 to 572 °F)
Fitted with adjustable wire mesh or aluminium trays

20. Hot Air Oven Thermostat digitally controls the temperature
Double walled insulation keeps the heat in and conserves energy
An air circulating fan helps in uniform distribution of the heat

21. Hot Air Oven Indicators and controls for temperature and holding time
These are widely used to sterilize articles that can withstand high temperatures

22. Advantages of Hot Air Oven
Does not require water
Not much pressure build up, making them safer to work with
Much smaller than an autoclave but can still be as effective
Faster than an autoclave
Rapidly reaches higher temperatures

24. Disadvantages of Hot Air Ovens
As they use dry heat instead of moist heat, some organisms like prions may not be killed by them every time

25. Chemical Sterilization
Liquid
Glutaraldehyde (Cidex)
Gas
Ethylene Oxide (ETO)
Formalin

26. Glutaraldehyde
The only liquid chemical capable of sterilizing an item is Glutataraldehyde (Cidex)

27. Glutaraldehyde Disadvantages
Extremely caustic to the skin, mucous membranes and other tissues
Carcinogenic
Short shelf life (<2 weeks)
Expensive
10 hours sterilization time

28. Gas Most effective is Ethylene Oxide (ETO) Disadvantages
Should only be used for items that will not withstand sterilization by steam under pressure
Disadvantages
3-7 hours sterilization time
Airing out period to allow ETO gas to be expelled from surface of item according manufactures instructions

29. One Chamber ETO Sterilizer

30. Two Chamber ETO Sterilizer

31. Chemiclave

32. Formalin Tablets
Sterilization of catheters, anaesthetic masks and valves, syringes, needles, small instruments, scopes like bronchoscopes, cystoscopes & items that cannot be autoclaved

33. Formalin Tablets
Effective against a wide spectrum of organisms and the storage of non-wrapped sterilized instruments
Used only in air tight containers like instrument cabinets using 10 tablets / dm3

34. Formalin Tablets

35. Formalin Tablets
Used as a fumigant in gaseous form, formaldehyde sterilization is complex and less effective
It should only be used if steam under pressure will damage the item to be sterilized and ethylene oxide and glutaraldehyde are not available

36. Formalin Tablets
No longer used in the United States, Canada, and Australia. The method dates back to 1820, but is still used in Europe and Asia

37. Disadvantages of Formalin Tablets
Caustic to the skin, mucous membranes and other tissues
Carcinogenic
Exposure time ranges from 15 to 24 hours

38. Points to Remember
Never sterilize surgical drains, disposable rubber gloves or disposable rubber catheters
An article is either sterile or unsterile-there is no in-between. If in doubt-consider it unsterile
If sterility field has been compromised-replace the contaminated field

39. Points to Remember
Do not open sterile articles until they are ready for use
Don’t leave sterile articles unattended once they are opened and placed on a sterile field
Do not return sterile articles to a container once they have been removed
Never reach over a sterile field

40. Points to Remember
When pouring sterile solutions into sterile containers or basins, do not touch the sterile container with the solution bottle
Discard any liquid remaining in the bottle
Never use an outdated article. Unwrap it and if re-usable, rewrap it in a new wrapper for sterilization

41. Questions 41

42. Thank You 42