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