AutoclaveSterilization /Desinfection
of materials
Unit of Tropical Laboratory Medicine
January 2012
Hilde De Boeck
DEFINITION
Autoclave
- Pressurized vessel
- A steam saturated environment permits obtaining
temperature >100°C
Autoclaving
- Submission to high pressurized steam for a period of
time.
Danger!!!
Decontamination
Stream sterilization
= total elimination of germs
(virus, fungi, bacteria, spores,..)
= reduction of contamination risk for person or environment
DEFINITION
Heat
dry/humid
Dry heat oven or “poupinel” Autoclave
Irradiation
Mechanical
Filtration
Gas Sterilization (ethylene oxide)
Disinfectant (gluteraldehyde)
STERILIZATION
ChemicalFysical
STERILIZATION
STEAM DRY HEAT OVEN
= “autoclave” = “Poupinel”
Standard : 121°C - 15 min Standard : 160°C - ≥2 h
“Autoclave” “Poupinel”
+Most reliable,
Fast Cheap
-Only for thermo/hydro resistant materials
Pressurized vessel « danger »Need for « driving license »
Installation $$Water consummation
+Simple Cheap
-Heat repartition: non uniform
Efficacy?? (spores of B. anthracis need 3h 140°C)
Deterioration of materialsVery long cycle
= reference method
STERILIZATION
4 basic Principles:
« Only sterilize what is clean »
« Only sterilize what is dry »
« Conservation of sterile state depends on packing»
« Always introduce “quality control”»
STERILIZATION
T refrigerator
T human body
Pasteurization T, kills bacteria in 30min.
Pasteurization T, kills bacteria in 15 sec.
Pasteurization T, kills bacteria in 3 sec
Autoclave: Kills spores in 15-30min
Dry heat: kills all spores in 2hrs
In theory 15min at 121°C are
sufficient to kill all germs but..
Penetration of humid heat
=> Elimination of all germs (viruses, fungi, spores, and bacteria)
=> Protein coagulation
STEAM STERILIZATION
NEEDED ON THE FIELD
Perfect absence of air
(no pocket)
(vapurised steam)
No vacuum pump on the autoclave (gravity
displacement autoclave)
Direct contact betweenitem and steam
Packing..
Stable temperature
(always > 121°C)
Electricity failure
Heater not always reliable
* if steam is not saturated, 1,05bar does not give 121°C
A safety margin is added (+5-25 minutes)When possible use 20min, 134°C
STEAM STERILIZATION
39 l
90 l50 l
STEAM STERLIZATION
3 essential parameters:
– Temperature
– Pression
– Time
Heating Sterilization Decompression End Cycle
121°C at 1,05bar
If one of these parameters is not respected => non reliable sterlization
STEAM STERLIZATION
GOOD PRACTICES - AUTOCLAVE
• Personnel Protective Equipment (PPE)
• Loading
• Operation
• Quality Control
• Documentation
• Unloading
PERSONEL PROTECTION
• Respect standard precautions
• Protective clothing
• Procedures (to be understand and know)
• Appropriate working conditions
Exposure to pathogenic agent (puncture, projections,..)
How to avoid injuries?
Personnel Protective Equipment (PPE)
Which PPE is recommended when manipulating an
autoclave?
• Personnel Protective Equipment (PPE)
• Loading
• Operation
• Quality Control
• Documentation
• Unloading
GOOD PRACTICES - AUTOCLAVE
LOADING
TO VERIFY BEFORE LOADING:
• Verify functionality of the autoclave:
put a register for communication (maintenance,
�Are all materials autoclave resistant?
non volatile, chlorine, etc.
�Wrapping of materials
�Does it allow steam penetration?
� Is it identified: indicator tape + date
�Can sterile condition can be maintained after?
AUTOCLAVABLE MATERIALS
• Glass wear
• Surgical instruments
• Solutions
• Contaminated waste: pipette tips, cultures,…
Prepare for steam sterliziation: packaging
Principle for critical items:
Must allow:
- Steam penetration
- Sterile status maintenance
Double packaging to permit “sterile” handling
Principle for semi-critical items:
Must allow:
- Steam penetration
- Clean storage
No “sterile handling “ needed
Prepare for steam sterliziation: packaging
Packaging – different materials
Cotton drapes
• High porousity
• Resistant
• Available everywhere
• Cheap
• Can be re-used
Kraft Paper: 0.16E/m2
• High porosity limits its use
• Not resistant
• Available everywhere
• Cannot be re-used
Crepe paper / sterilization paper: 0.27E/m2
• Low porosity (50µ) allows maintenance of sterile status, when used double
layer
• Not available everywhere
• Not resistant
• Cannot be re-used
Packaging – different materials
Drums:
• Can be re-used
• Resistant
• Residual water in corner
(no efficient drying system in out autoclave)
• For critical items?not optimal because closure after sterlization
⇒ Need for first packaging (crepe – kraft)
⇒ One drum = one interventions
Packaging – different materials
Box with filter
- Filter must be changed
- Expensive
- Residual water in corner
Packaging – different materials
Others
Newspaper
Packaging – different materials
Packaging – different materials
Efficiency for maintenance of sterile status .. No
study about it..
LOADING
• Assure free circulation of steam
=> don’t overload (max. 75%)
• No direct contact with water or autoclave
• different cycles for decontamination and sterilization
• Avoid accumulation of water in the recipients
LOADING
SOLUTIONS
• (in general) don’t completely close off container
• Preferably use borosilicate (Pyrex)
• Don’t completely fill the recipients (max. 50-75%)
• different volumes => different timing
– 250mL => 20min.
– 500mL => 30 min. use homogenous load
• Use secondary recipients (spills)
• Allow cool down before opening autoclave
• Close recipients after unloading them
GOOD PRACTICES - AUTOCLAVE
• Personnel Protective Equipment (PPE)
• Loading
• Operation
• Quality Control
• Documentation
• Unloading
• Personnel Protective Equipment (PPE)
• Loading
• Operation
• Quality Control
• Documentation
• Unloading
GOOD PRACTICES - AUTOCLAVE
Autoclave PBFifty
OPERATION
Put PROCEDURES
in place
OPERATION
PROCEDURES: SIMPLE ET COMPREHENSIVE!
• Close the water (5) and steam (3) tap
• Introduce 3L of distilled water in the chamber
• Introduce the load
• Cloase of the 6 handles
• …
DON’T FORGET MAINTENANCE!!
-> Frequence: 1x/week-> Responsable
• Personnel Protective Equipment (PPE)
• Loading
• Operation
• Quality Control
• Documentation
• Unloading
GOOD PRACTICES - AUTOCLAVE
Possibilities?
Doesn’t guaranty efficiency$$$$
Sterilization « controls »
Biological indicatorsTape = Indicator
Cycle controls
TST control (time, temperature)
Place in middle of loadCheck color shift blue/violet
DOCUMENT
Traceability in case of problems
Sterilization « controls »
Mois: ………………….
Nº Date Autoclave
Paramètre de sterilization Chargement
TVTRemarqueSignatureTemp
s Temp
1/0518/5
PBFifty 20m 121°C Milieu MacConkey TSA
2/05 19/5 Tommy 1h 121°C
3/05 20/5
4/05 30/5
REGISTER: QC
Déchets biologique
INTRODUCTION
CYCLE VALIDATION
= external control
= what happens in reality
CYCLE VALIDATION
TOOLS:
Allows real-time follow-up of temperature and pressure
Start cycle00:10
T>120°C
01:28- 01:34Start cycle00:10
Lid Open
Tmax.: 120°CT> 120°C = 6min.
T>120°C
01:28- 01:34End02:20
Tmax.: 122,1°CT> 121°C = 16min.
Start cycle00:40
Evacuation Vapeur
Ouverture01:52
> 121°C
01:04 to 01:20 (16min)
Installation autoclave HSLK, Kisantu, DRC
Intended Use:• Preparation culture medium• Destruction hemoculture bottles
Installation autoclave HSLK, Kisantu, DRC
• Personnel Protective Equipment (PPE)
• Loading
• Operation
• Quality Control
• Documentation
• Unloading
GOOD PRACTICES - AUTOCLAVE
UNLOADING
• Never open a pressurised chamber
• Wait untill temperature drop (<75°C)
• Leave solutions to cool down
• Close off recipients
• Perform QC
DRY HEAT STERILIZATION
“POUPINEL”160°C ≥2 h
RECYCLING OF LABORATORY MATERIALS- glass petri dish- glass tubes, bottles- …
NOT CRITICAL ITEMS
ATTENTION:- Don’t overload - Never open during cycle - Wrap (paper, aluminum) or use immediately
DRY HEAT STERILIZATION
Dry Heat => Wrap materials to keep them in sterile state!!! When autoclaving you need contact with steam!!!
DRY HEAT STERILIZATION
RECYCLING MATERIALS
Objective:
Always have a stock of necessary sterile materials
• Put the date of sterilization
– FIFO (First In, First Out )
• Use indicator tape (only for ID!)
RECYCLING CYCLE
COLLECTION
DESINFECTION/DECONTAMINATION
CLEANING
STERLIZATION
STORAGE
3 STEPS
RECYCLING CYCLE
COLLECTION“Dirty” Zone
minimum 1x/day
Avoid contamination (storage and transport)
Use container (bucket,..) with lid
Use PPE (gloves, coat,…)
Organize – Keep order!
DESINFECTION/DECONTAMINATION
CLEANING
STERLIZATION
STORAGE
COLLECTION
DESINFECTION/DECONTAMINATION
Why? Lower amount of micro-organisms
to protect staff when manipulating
+ Helps the cleaning afterwards
Eau de javel 24h
CLEANING
STERLIZATION
STORAGE
Alternative:
Autoclave
RECYCLING CYCLE
A different cycle is used (than for sterilization)
DESINFECTION USING AUTOCLAVE
⇒121°C for 1h
= Security buffer
Use a 2nd recipient for spills
Direct contact with steam
- Partially open recipient
- Partially open autoclave bags
COLLECTION
DESINFECTION/DECONTAMINATION
CLEANING
« You can only sterilize what is clean »
« You can only sterilize what is dry »
Soak in soap and water
Carefully clean
Rinse with water (distilled)
Dry
Pack
Storage in « clean » zone
STERLIZATION
STORAGE
RECYCLING CYCLE
COLLECTION
DESINFECTION/DECONTAMINATION
CLEANING
STERLIZATIONWITH STEAM WITH DRY HEAT
STOCKAGE
= “autoclave” = “Poupinel”
In general: 121°C - 20 min In general : 160°C - ≥2 h
RECYCLING CYCLE
COLLECTION
DESINFECTION/DECONTAMINATION
CLEANING
STORAGE
Conservation of sterile state
« STERILE » zone
Protected from dust
Organize
New sterilized behind older (FIFO)
RECYCLING CYCLE
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