1. Autoclaves – principles and function
Dr. S. Parthasarathy MD. DA. DNB. PhD., FICA.,
Dip. software based statistics

2. What we don’t want after surgery
Infection
Lister started – 1867
We continue
Asepsis and sterilization
Numerous methods

3. Physics !! Water boils at 100 degrees Boiling point is 100 degrees
Supplied heat – temperature rises only up to 100. then liquid turns into vapor

4. Physics The boiling point will vary with ambient pressure
In pondicherry – it is 100
In ooty – it may be only 80
If we create high pressures it may boil only at 120 degrees

5. Physics supplied heat to water Steam comes out at 100 -------
Close the chamber to create high pressure
Boiling point rises to 120
Steam generated at 120 instead of 100
High temperature is ideal to sterilize

6. Pot and the pressure cooker
Rice cooked more effectively and faster in pressure cookers
High temperature which does than pressure

7. Autoclave It was invented by Charles Chamberland in 1879
Still it rules ??

8. Uses Medical Industrial Chemical All instruments Linen Towels
Gauze pieces
Mopping pads
All except
sharp instruments
Plastic, Screw drivers
Medical
Industrial
Chemical

9. No ---------------- yes

10. Double walled

11. Mechanism Water down – close Heat Displaces air ?? ( kitchen )
Steam to pressure – kpa
Switch off ( 121 degrees)
15 minutes
Pressure release – moist heat ??
Use
1 atm = 100 kpa = 14.6 psi

13. Indicators

14. Chemical !!

15. Empty glassware and unwrapped instruments
Empty glassware and unwrapped instruments. Sterilizing time 15 minutes, drying 10 minutes.
Wrapped instruments, rubber gloves, tubes and catheters, and sutures being reautoclaved. A common regime is 0.7 kgcm, (10 lb per square inch) for 20 minutes.
Fabrics and dressings. Sterilizing time 20 minutes, drying 15 minutes.
Liquids in flasks and bottles. Sterilize 100 ml bottles for 20 minutes, 300 ml bottles for 30 minutes, 500 ml bottles for 35 minutes, 1000 ml bottles for 40 minutes,

16. Advantages Nontoxic to patient, staff, environment
Cycle easy to control and monitor
Rapidly microbicidal including spores
Least affected by organic/inorganic soils among sterilization processes listed
Rapid cycle time
Penetrates medical packing, device lumens

17. Disadvantages Deleterious for heat-sensitive instruments
Microsurgical instruments damaged by repeated exposure
May leave instruments wet, causing them to rust
Potential for burns

18. summary Thank you Sterilization methods Principle Types Methodology
Advantages
Disadvantages
Thank you