Cleaning Decontamination, Disinfection and Sterilization Process

– an example of the person-machine interface that is so visible in the delivery of healthcare.

entral terile upply

• Responsible for collecting and receiving patient care items, instruments and devices used during the provisions of healthcare.

• For decontaminating, processing, sterilizing, storing and dispensing items to all parts of the hospital.

• Receiving Area

• Clean and Decontamination Area

• Preparation and Packaging Area

• Sterilization Area

• Sterile Storage Area

FIG. 1 FUNCTIONAL FLOW

Used Instrument from variousdepartment

Sort

Clean and Decontaminate

High levelDisinfection

Pack

Sterilization

Storage

Distribution

FIG. 3. Typical Layout of S.S.D.Used Loads Entry Point

Decontamination Area

Assembly Area

Processing Area

Packaging Area

Sterilization Area

S1 S2 S3

Sterile Goods Storage AreaSterile Goods Distribution Point

Definition of Terms

Removal usually with detergent and water or enzyme

cleaner and water , Of adherent visible

soil, blood, protein substances

microorganisms and other

debris from the surfaces, crevices,

serrations, joints, and lumens of

instruments, devices, and equipment

by a Manual or mechanical process that

prepares the items for safe handling and

or further decontamination.

The first and the most important step in decontamination

is thorough cleaning and rinsing.

To remove all visible debris from an item and to reduce the

number of particulates, microoganisms and potential

pyrogenes.

Definition of Terms

• Non abrasive

• Low – foaming

• Free – rinsing

• Biodegradable

• Rapidly dissolve/ disperse soil

• Non Toxic

• Efficacious on all types of clinical soil

• Have long shelf life

• Cost effective

Properties of an ideal cleaning agent:

Cleaning Methods

1. Manual Cleaning – Recommended for delicate

or complex medical devices. Example:

Microsurgical instruments, air powered drills.

2. Mechanical Cleaning – Removes soil and

microorganisms through an automated

cleaning and rinsing process. Examples:

Washer sanitizers/disinfectors

Ultrasonic Cleaners.

Principle

1. Thorough cleaning is required before high level

disinfection.

2. Surgical instruments should be pre-soaked or Rinse. Pre-

soaking with a specialized product (e.g. enzymatic

solution) referring to the manufacturers instructions,

correct dilution, temperature and soak time.

3. Done Manually in use areas without mechanical units or

for fragile or difficult – to clean instruments.

4. Friction and Fluidics are the two(2) essential

components:

• Friction (e.g. rubbing / scrubbing with a Brush)

• Fluidics (i.e. fluids under pressure) – to remove soil and

Debris from internal channels after Brushing.

Cleaning Precautions :

Information contained in the Material

Cleaning Precautions :

Cleaning Agents

Washing / Rinsing Methods

Drying of instruments

Recommended Practice :

SHARPS:

• Avoid recapping used needles.

• Avoid removing used needles from

disposable syringes.

• Avoid bending, breaking or manipulating

used needles by hand.

• Place used sharps in puncture-resistant

containers.

Standard/Transmission – Based

(enhanced) Precautions:

Any micro-organism in the

wrong place at the right

time is a potential

pathogen.

Important Points to Remember

Decontamination

The use of physical or chemical means to remove,

inactivate, or destroy blood borne pathogens in

surface or item to the point where they are no

longer capable of transmitting infectious

particles and the surface of the item is rendered

safe for handling use, use or disposal of all

pathogenic organisms.

Cleaning and Decontamination should begin as

soon as possible after items have been used .

Adequate cleaning is the first step in the

decontamination and reuse process.

Decontamination

Decontamination

Decontamination

Decontamination

Disinfection

• Thermal or Chemical destruction of

pathogenic and other types of

microorganisms.

• Less lethal than sterilization because it

destroys recognized pathogenic

microorganisms but not necessarily all

microbial forms (Bacterial Spores)

SPORES

• Relatively water-proof round or elliptical

resting cell consisting of condensed

cytoplasm and nucleus surrounded by an

impervious cell wall or coat.

• Relatively resistant to disinfectants and

sterilant activity and drying conditions

(specifically in the genera Bacillus and

Clostridium).

B subtilis spores

Clostridium_tetaniClostridium botulinum spores

Disinfection

Disinfection

Disinfectant

Usually a chemical agent (but sometimes a

physical agent) that destroys disease – causing

pathogens or other harmful microorganisms but

might not kill bacterial spores

Properties of an ideal Disinfectant

1. Broad Spectrum:

◘ Should have a wide antimicrobial

spectrum.

2. Fast acting:

◘ Should produce a rapid kill.

Properties of an ideal Disinfectant

Properties of an ideal Disinfectant

Properties of an ideal Disinfectant

Before Sterilization

and High Level

Disinfection can be done:

MUST decontaminate

MUST clean and rinse

instruments and

equipments

Justification for use of Disinfectants

for Non- Critical Environmental

Surfaces

1. Surfaces may contribute to transmission of

epidemiologically important microbes (e.g.

Vancomycin-resistant Enterococci, methicillin-

resistant S. aureus, viruses).

2. Disinfectants are needed for surfaces

contaminated by blood and other potentially

infective material.

3. Disinfectants are more effective than detergents

in reducing microbial load on floors.

4. Detergents become contaminated and result in

seeding the patient’s environment with bacteria.

4. Disinfection of non-critical equipment and

surfaces is recommended for patients on

isolation precautions by the CDC.

6. Advantage of using single product for

decontamination of non-critical surfaces, both

floors and equipment.

7. Some newer disinfectants have persistent

antimicrobial activity.

Some of the Common Disinfectants:

GUIDELINES

FOR THE USE OF SOME COMMON

DISINFECTANT

DISINFECTANT RECOMMENDED USE PRECAUTIONS

Sodium Hypochlorite(Bleach)

» Should be used in well ventilated areas, causedirritation of skin, eyesand lungs if used inpoorly ventilated areas.

» Protective clothing required while handlingand using undiluted.

» Do not mix with strong acids to avoid release ofchlorine gas.

» Corrosive to metal

Bleaching powder Toilets, bathrooms, may be used in place liquid bleach if liquid bleachis not available

Disinfection of materialcontaminated With blood andbody fluids (remove Grosscontamination before disinfection).

» Same as above

DISINFECTANT RECOMMENDED USE PRECAUTIONS

Alcohol (70%)isopropyl, ethylalcohol, methylatedspirit

» Flammable, toxic, to beused in well ventilatedarea, avoid inhalation, usefor small surface only.

» Kept away from heat source, electrical equipment, flames, hotsurfaces.

» Allow it to dry completely,particularly when usingdiathermy as it can causediathermy burns.

Smooth metal surface, table tops surfaces on which bleachcannot be used. In combinationwith skin emollients can be used for disinfection of hands.pre operative preparation ofskin.

Alcoholic hand rub (70% isopropanol towhich 1% glycerine isadded

In all clinical setting for theDisinfection of hands

» Same as above

DISINFECTANT RECOMMENDED USE PRECAUTIONS

Glutaraldehyde (2%) » Eye and nasal irritant, maycause asthma and skinallergies, hence use in wellventilated area, keepcovered with well fittinglids.

» Toxic : (Colitis, Keratopathy,Corneal decompensation ifadequately rinse.

» Mucous membrane irritation,Epistaxis, Rhinitis

» Eye protection, plasticapron and gloves shouldbe worn while handling.

» Need 7-15 air exchange/hour

For disinfection of endoscopes,respiratory therapy equipmentand for materials that aredestroyed by heat. Can work as a sterilant if contact time is 10hours and if used under strictlycontrolled condition.

Detergent with enzyme

Cleaning endoscopes, surgicalinstrument before disinfection.

DISINFECTANT RECOMMENDED USE PRECAUTIONS

Clear solublephenolics (2%solution)

» Protective clothing shouldbe worn while handling asit can be absorbed throughthe skin and causerespiratory irritation inhigher concentrations.

» Must not be used in equipment coming incontract with skin andmucous membranes, orshould not be used onfood preparation surfaces.

» Should not be used in Nurserycan cause Hyperbilirubinemia

Only environmental disinfection,mycobacteria laboratory discardjars.

DISINFECTANT RECOMMENDED USE PRECAUTIONS

Formaldehyde (40%solution: formalin)

» Potent eye and nasalirritant may cause respiratory distress andskin allergy.

» Protective clothing suchas gloves, eye protectionand gowns should be worn.

» Use in well ventilated area.

» Carcinogenic

Chlorhexidine: combined withalcohol or detergents(eg Hibiscrub).

Antiseptic, for skin and mucousmembranes, preoperative skinpreparation, disinfection of hands.

» Inactived by soap,organic matter.

» Relatively non toxic» Do not allow contact with

brain meninges, eye ormiddle ear.

For preparing viral vaccine (e.g. polio virus and influenza), as anembalming agent to preserve anatomic specimens.

DISINFECTANT RECOMMENDED USE PRECAUTIONS

Iodine or iodophors:Can be combined withalcohol or detergents(eg betadine, tinctureIodine)

» Iodophor is less irritantthan iodine.

» Can cause skin allergy.» Gloves to be used for

prolonged contact» May corrode metals

Antiseptic, for pre operative skinand hand disinfection.

Quaternary Ammonium Compounds: (eg dettol) May be combined withchlorhexidine.

Antiseptic, for cleaning dirtywounds.(Low level disinfection only)

» Relatively non toxic» Contamination and growth

of gram negative bacteriaare likely in use dilutions.

Hence:

» Use in correct dilution inhigh level disinfectedcontainers.

» Change in use solutionevery 8 hours.

» Do not top up stock bottle

DISINFECTANT RECOMMENDED USE PRECAUTIONS

Hydrogen Peroxide » Stains skin, clothing andenvironmental surfaces,

Eye irritation with contact

Bactericidal, virucidal, sporicidal,and fungicidal properties

Use in endoscopes, inanimate surfaces, ventilators, fabrics

“When properly used, Disinfection

and Sterilization can ensure the

safe use of invasive and non-

invasive medical devices.”

“However current Disinfection and

Sterilization Guidelines must be

strictly followed”

Hp decontamination system

Outcome:

C. Difficile incidence

Results:

HPV decreased environmental

contamination with C. Difficile

Rates on high on floors from 2.28to

1.28cases per 1,00o pt days and throughout

the hospital from 1.38 to 0.84 cases per

1,000 pt days

(Boyce,JM,et al)

Advantages of HP system

1. Reliable biocidal activity against wide

range of pathogens

2. Surfaces & equipment decontaminated

3. Demonstrated to decrease disease

incidence(C.Difficile)

4. Residual free does not give rise to health

& safety concerns (aeration units convert

HP to oxygen & water

5.Useful for disinfecting complex equipment

& furnitures.

C. difficile spore can survive in the hospital

environment for up to 5 months.

Vegetative C. difficile can remain viable on moist surfaces

(toilets. sinks, moist dressing) up to 3 hours in room air.

Recently, room disinfection with vaporized hydrogen peroxide

has also been found to reduce C.difficile incidence rates

Survival of Selected Microbes on Environmental Surfaces

MICROORGANISM Duration of Survival

Acinetobacter spp. 3 days – 5 months

Clostridium difficile 5 months – 1 year? Spore15 min- 3 hrs: vegetative form

Enterococci (incl. VRE) 5 days to 4 months

Serratia marcescens 3 days – 2 monthsDry floor = 5 weeks

Staphylococcus aureus (incl. MRSA) 7 days – 7 months

Hepatitis B virus (HBV) ≥ 1 week

Human Immunodeficiency virus (HIV) 3 – 4 days

Norovirus 8 hrs – 7 days

Kramer A. BMC ID 2006; McFarland L, et al. AJIC 2007

Metals as Microbicides

• Metals such as silver, iron and copper could

be used for environmental control,

disinfection of water or reusable medical

devices or incorporated into medical

devices.

References:• RUTALA, WA (editor) Disinfection, Sterilization and Antisepsis

Principles, Practice, Current Issues, New Research & New

Technology, Association for Professionals in Infection Control

and Epidemiology, Washington DC,2010.

• Practical Guideline for Infection Control in Health Care

Facilities, WHO

• disinfectionandsterilization.org

STERILIZATION PROCESS

Cleaning

Inspection/ assembly

Packaging

Sterilizer loading

Sterilization

Storage

METHOD OF STERILIZATION

Moist and Heat

Hot air Oven

Ionizing radiation

Ethylene Oxide

Low Temperature steam and formaldehyde

Chemical disinfection sterilization

METHOD OF STERILIZATION

◘ Moist heat (autoclave)

• Autoclave at 121°C for 15 min or 134°C for 3 min

◘ Hot air oven (oils, powder, glassware & needles)

• 160°C for 2 hours • 180°C for 30 min

◘ Ionizing radiation

• i.e. sutures • 3 to 6 hours exposure

◘ Ethylene Oxide (EO)

• For heat and moisture sensitive product like

plastic goods and sharps

• 37°C -55°C up to 6 hours

METHOD OF STERILIZATION

◘ Chemical Sterilization

• Sporicidal disinfectant (sterilant)

• 2% Glutaraldehyde used for heat

sensitive equipment 3 to 10

hours

All sterilizing systems have inherent

limitations and no single system can

be used effectively for all instruments

and devices.

Methods to Control the Sterilization Process

Monitoring the Sterilization process is an important quality – assessment procedure for Infection Control in CSS . The three forms of monitoring are :

1. Physical Monitoring : Observing and recording the parameters of sterilizationfunctioning (e.g. time, temperature, pressure, gas concentration)

2. Chemical Monitoring : Color or physical changes indicators that monitor exposes to sterilizing agents or conditions.

3. Biological Monitoring : Spore testing, the most important check on sterilization Function.

Physical and Chemical Indicators are used to indicate that the sterilization procedure are performed and to ensure proper packing, sterilizer load configuration and function of the process equipment.

Sterilization Process

• Decontamination

• Inspection / assembly

• Packaging

• Sterilizer loading

• Sterilization

• Storage / distribution /documentation

Surgical Instrument Cleaning DecontaminationProcess

Receiving

Disassembly

Cleaning

Rinsing

Disinfecting

Drying

Factors that can affect the efficacy of

Steam Sterilizers

◘ Air tightness of the sterilizer

◘ Atmospheric pressure

•Low Atmospheric pressure = Air leak

◘ Quality of steam

• Need 100% saturated steam & water in the system

• Need steam separator and baffle to remove

the water from the steam at required velocity

• Decreased steam quality = Trapped air

= WET PACKS

◘ Leaks in the system = uneven heating and spot

dry condition

Monitoring the Sterilization Process

Chemical Indicator

◘ External - shows only exposure to a process

- does not indicate all parameters were met.

- safeguards distribution

◘ Internal Indicator

- shows exposure to the internal contents

- demonstrate exposure to one or more

of the conditions necessary for sterilization

- sterilant must penetrate the package long

enough to change the color indicator or

- change the color to a certain distance along

the bar of an “Integrator”

Biological Indicator (BI)

A device that has been impregnated

with a Known population and type of

micro-organisms (Spores) used to

verify that all conditions necessary

for sterilization have been met.

Most BI’s contains from 100,000 to

1,000,000 bacterial spores.

Sterility Maintenance

After sterilization, items should be placed in low

traffic area.

Steam load should be allowed to cool for a

minimum of 30 minutes.

Never transport warm items from the sterilizer to

cold surface (racks, shelves, counters, etc) as this

can cause condensation to form, resulting in

contamination.

HANDLING AND INSPECTION

Sterile items that are torn or wet are considered

contaminated and should be reprocessed.

STERILE STORAGE

Sterility maintenance bags (dust covers) may be

used to protect items that could be subjected

to environmental challenges or multiple

handling before use.

Close or cover cabinets are ideal for Storing

sterile items.

They limit dust accumulation, minimize handling

and inadvertent contact.

Open shelving maybe used,

but should be :

• 2” from outside walls

• 8 to 10” from floor

• 18” from ceiling

• not crunched, bent, compressed, punctured or

near any location that could become wet.

SHELF LIFE

“ Shelf life of packaged sterile items is event

related and depends on the quality of the

Packaging material, the storage conditions,

the conditions during transport and the amount

of handling.”

Distribution

Sterile items should be visually inspected for

Integrity and labeling prior to being issued.

Transporting sterile items in “uncontrolled

environments” should be in a covered or

enclosed cart with a solid bottom shelf

Carts should be decontaminated and dried before

reuse for transporting sterile supplies.

Transporting sterile items inside plastic bags or

boxes should be arranged within the containers

as to prevent crushing, damage or

contamination.