Cleaning, Disinfection, and Sterilisation. Learning Objectives 1.Differentiate between disinfection...

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Cleaning, Disinfection, and Sterilisation

Transcript of Cleaning, Disinfection, and Sterilisation. Learning Objectives 1.Differentiate between disinfection...

Cleaning, Disinfection,and Sterilisation

Learning Objectives

1. Differentiate between disinfection and sterilisation.

2. Explain different types of sterilisation.3. Outline the process for cleaning patient

care items.

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Time involved

• 90 minutes

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Key points - 1

• Cleaning, disinfection, and sterilisation are the backbone of infection prevention and control

• Proper cleaning essential before any disinfection or sterilisation process

• Failure to sterilise or disinfect reusable medical devices properly may spread infections

• The type and level of device decontamination depends upon the nature of the item and its intended use

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Key points - 2• Steam sterilisation effective only when preceded

by • Thorough pre-cleaning, proper packaging/loading, and

careful monitoring of autoclaves

• Chemical disinfectants must be selected, used, and discarded to minimise harm

• Those responsible for processing contaminated items must be fully trained and wear protective clothing when necessary

• Clearly written policies and procedures must be available on-site for training personnel and for monitoring their performance

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Decontamination

• A process of treatment that renders a medical device, instrument, or environmental surface safe to handle

• Does not necessarily mean that the item is safe for patient reuse

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Pre-Cleaning/Cleaning

Everyone responsible for handling and reprocessing contaminated items must:

• Receive adequate training and periodic retraining• Wear appropriate personal protective equipment

(PPE)• Receive adequate prophylactic vaccinations

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Spaulding Classification

Divided hospital instruments into general categories based on the risk of infection involved in their use

• Critical items• Semi critical item• Non critical items

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Critical Items

• Enter normally sterile tissues, the vascular system, or equipment through which blood flows

• Items must be properly and safely pre-cleaned and sterilised before use

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Critical Items - Examples

• Implants• Prosthetic devices• Surgical instruments• Needles• Cardiac catheters• Urinary catheters• Biopsy forceps of endoscope

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Semi-critical Items

• Contact mucous membranes but do not penetrate soft tissue or body surfaces

• Meticulous physical cleaning followed by appropriate high-level disinfection

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Semi-critical Item - Examples

• Flexible fiberoptic endoscopes• Respiratory therapy equipment• Anaesthesia equipment• Endotracheal tubes• Bronchoscopes• Vaginal specula• Cystoscope• Hand-piece

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Non Critical Items

• Direct contact with the patients intact skin (unbroken skin)

• Little risk of pathogen transmission directly to patient

• Clean and disinfect using a low to intermediate level disinfectant

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Examples of Non Critical ItemsItems which are in contact with intact skin

• Bedpans• Blood pressure cuffs• Crutches• Stethoscopes• Face mask• X-ray machine

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Disinfection

A process that eliminates many or all pathogenic microorganisms on inanimate objects, with the exception of bacterial spores

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Sterilisation - 1

• The complete elimination or destruction of all forms of microbial life

• Includes large numbers of highly resistant bacterial spores

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Sterilisation - 2

• Store in clean, dry place• Protect wrapping• Inspect before use D

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Staff Training and Protection

• Written and up-to-date policies and procedures must be available on-site for training/monitoring staff responsible for device reprocessing

• Train staff fully and retrain as necessary; maintain written records

• The staff must also be provided with:• Personal protective equipment (PPE)• Prophylactic vaccinations

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Single-Use Items

• Single-use items must be safely discarded after use• e.g., injection needles

• No reprocessing before carefully considering the following: • Is device undamaged and functional? • Can it be disassembled for reprocessing? • Can its sterility be validated, if needed? • Is the reprocessing cost-effective? • Is an authorised person onsite willing to be

responsible for any negative consequences?

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Choice of Method

• Method to be used will depend on: • Device’s intended use• Risk of infection • Degree of soilage

• Process must not damage the device

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Disinfection

• Reduction in numbers of pathogens on inanimate surfaces/objects • For items that will contact intact skin or mucous

membrane• Use physical or chemical agents or both

• Level of disinfection• High-level• Intermediate-level• Low-level

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High-level Disinfectants - 1

• Active against vegetative bacteria, viruses (including the non-enveloped ones), fungi, and mycobacteria

• May have some activity against bacterial spores• With extended contact times

• HLDs are used to disinfect heat-sensitive and semi-critical devices • Such as flexible fibreoptic endoscopes

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High-level disinfectants - 2

• HLDs typically require 10-45 minutes contact time • Depends on the temperature

• After disinfection, items require thorough rinsing/flushing with sterile or filtered water to remove any chemical residues• They must then be dried with an alcohol rinse or by

blowing clean, filtered air through the device’s channels prior to storage

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Intermediate-level Disinfectants

• Active against vegetative bacteria, mycobacteria, fungi and most viruses

• May fail to kill spores, even after prolonged exposure

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Low-level Disinfectants

• Active against vegetative bacteria (except mycobacteria), some fungi, and only

enveloped viruses • In many cases, washing with unmedicated

soap and water would be sufficient in place of LLD

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Chemical disinfectants in health care

Agents Spectrum Uses Advantages Disadvantages

Alcohols (60-90%) includingethanol and isopropanol

Low- to intermediate-level disinfectant.

Used for decontaminating the outside of some semi-critical and noncritical items, e.g., oral and rectal thermometers and stethoscopes. Also to disinfect small surfaces such as rubber stoppers of multi-dose vials. Alcohols with detergent are safe and effective for spot disinfection of countertops, floors, and other surfaces. Also common in handrubs.

Fast acting.No residue.Non-staining.Low cost. Widely available in many countries for medicinal and research purposes.

Volatile, flammable, and an irritant to mucous membranes.Inactivated by organic matter.May harden rubber, cause glue to deteriorate, or crack acrylate plastic.

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Chemical disinfectants in health care

Agents Spectrum Uses Advantages Disadvantages

Chlorine and chlorine compounds: the most widely used is an aqueous solution of sodium hypochlorite 5.25-6.15% (domestic bleach) at a concentration of 100-5000 ppm free chlorine

Low- to high-level disinfectant.

Used for disinfecting tonometers and for spot disinfection of countertops and floors. Can be used for decontaminating blood spills. Concentrated hypochlorite or chlorine gas is used for disinfection of large and small water distribution systems, such as dental appliances, hydrotherapy tanks, and water distribution systems in haemodialysis centres.

Low cost, fast acting. Readily available in most settings. Available as liquid, tablets or powders.

Corrosive to metals in high concentration (>500 ppm). Inactivated by organic material.Decolourises or bleaches fabrics. Releases toxic chlorine gas when mixed with ammonia. Irritant to skin and mucous membranes. Unstable if left uncovered, exposed to light, or diluted; store in opaque container.

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Chemical disinfectants in health care

Agents Spectrum Uses Advantages Disadvantages

Aldehydes

Glutaraldehyde: ≥2% alkaline or acidic solutions. Also formulated with phenol-sodium-phenate and alcohol.

High-level disinfectant.

Widely used as high-level disinfectant for heat-sensitive semi-critical items such as endoscopes.

Good material compatibility.

Allergenic and irritating to skin and respiratory tract. Must be monitored for continuing efficacy levels when reused.

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Chemical disinfectants in health care

Agents Spectrum Uses Advantages Disadvantages

Ortho-phthalaldehyde (OPA) 0.55%

High-level disinfectant.

High-level disinfectant for endoscopes.

Excellent stability over wide pH range. Superior mycobactericidal activity compared to glutaraldehyde. Does not require activation.

Expensive. Stains skin and mucous membranes; may stain items not thoroughly cleaned. Eye irritation. Poor sporicide. Must be monitored for efficacy during reuse. Contraindicated for reprocessing certain urological instruments.

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Chemical disinfectants in health care

Agents Spectrum Uses Advantages Disadvantages

Peracetic acid 0.2-0.35% and other stabilised organic acids.

High-level disinfectant/sterilant.

Used in automated endoscope reprocessors. Can be used for cold sterilisation of heat-sensitive critical items, e.g., haemodialysers. Also suitable for manual instrument processing when properly formulated.

Rapid sterilisation cycle time at low temperature (30-45 min. at 50-55oC). Active in presence of organic matter. Environmentally-friendly by-products (oxygen, water, acetic acid).

Corrosive to some metals.Unstable when activated. May be irritating to skin, conjunctivae and mucous membranes.

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Chemical disinfectants in health care

Agents Spectrum Uses Advantages Disadvantages

Hydrogen peroxide 7.5%.

High-level disinfectant/sterilant.

Can be used for cold sterilisation of heat-sensitive critical items. Requires 30 minutes at 20oC.

No activation. No odour.Environmentally-friendly by-products (oxygen, water).

Not compatible with brass, copper, zinc, nickel/silver plating.

Hydrogen peroxide 7.5% and peracetic acid 0.23%

High-level disinfectant/sterilant.

For disinfecting haemodialysers.

Fast-acting (high-level disinfection in 15 min.). No activation required. No odour.

Not compatible with brass, copper, zinc, and lead. Potential for eye and skin damage.

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Chemical disinfectants in health care

Agents Spectrum Uses Advantages Disadvantages

Phenolics Low- to intermediate-level disinfectant.

Has been used for decontaminating environmental surfaces and non-critical items. Concerns with toxicity and narrow spectrum of microbicidal activity.

Not inactivated by organic matter.

Leaves residual film on surfaces. Harmful to the environment. No activity against viruses. Not recommended for use in nurseries and food contact surfaces.

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Chemical disinfectants in health care

Agents Spectrum Uses Advantages Disadvantages

Iodophores (30-50 ppm free iodine)

Low-level disinfectant. Used on some non-critical items, e.g., hydrotherapy tanks; however, main use is as an antiseptic.

Relatively free of toxicity or irritancy.

Inactivated by organic matter. Adversely affects silicone tubing. May stain some fabrics.

Quaternary ammonium compounds

Low-level disinfectant unless combined with other agents.

Used mainly on environmental surfaces. Can be used on skin.

Stable with good detergent properties (cationic detergent). Usually non-irritating.

Relatively narrow microbicidal spectrum, but range of activity can be expanded when combined with other agents, e.g., alcohols.

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Practical Tips - 1• Develop a policy for chemical disinfection• Disinfectants may be supplied ready to use or

may need to be diluted• Label bottles or containers with the name and

concentration of disinfectant and, for diluted disinfectants, the date of dilution/preparation

• Prepare dilutions with clean water• Prepare small amounts at a time to avoid

wastage

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Practical Tips - 2

• Do not mix freshly made diluted solution with old solution

• Wash and dry the container before filling with new solution

• Clean, rinse and dry items thoroughly before disinfecting

• After disinfection, rinse thoroughly with clean water to remove all chemical residues

• Alcohol solutions can be allowed to dry without rinsing

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Steam Sterilisation

• Requires direct contact of an item with steam at a required temperature and pressure for a specified time

• Most reliable• Non-toxic • Has broad-spectrum microbiocidal activity• Good penetrating ability• Cheap and easy to monitor for efficacy• 2 main types: gravity and pre-vacuum 36

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Gravity Displacement Autoclaves

• Steam introduced to purge out air and build pressure

• Raise temperature normally to 121°C at 15 pounds/square inch and maintain it for 15-45 minutes

• For sterilising liquids and items in wraps that steam can penetrate

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High-Vacuum Autoclaves

• Air is first vacuumed out and then steam introduced

• Faster and better penetration throughout the load

• Pressure and temperature higher; 134°C at about at 30 pounds/inch2

• Processing time about three minutes • Not suited for liquids due to need for

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Factors Influencing Steam Sterilisation

• Proper loading must occur• All items in load must have contact with

steam• Items in load must be free from grease

and oil

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Practical Tips

• A wide range of sterilisers is available• Always sterilise items for the correct time

using a clock or timer• Air in the steriliser and load results in

inadequate steam penetration• Never sterilise single use items

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Low-Temperature• Mixture of steam (50-80°C) and

formaldehyde vapour • To process heat-resistant or heat-

sensitive medical devices in specialised equipment

• Devices pre-cleaned and wrapped in standard material and processed in a three-hour cycle

• Cannot be used for liquids• Formaldehyde must be purged/

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Flash Sterilisation

• Only to process a critical surgical item:a) in an emergencyb) when accidentally contaminated, or c) when other means of sterilisation unavailable

• Never to be used for implantable items or to compensate for shortage of key instruments

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Dry Heat Sterilisation - 1

• Require hot-air ovens• For glassware, metallic items, powders and

oil/grease • Time two hours at 160°C and one hour at 180°C• Plastics, rubber, paper and cloth cannot be

placed in them due to fire risk

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Dry Heat Sterilisation - 2Advantages• Can be used for powders, anhydrous oils• Inexpensive• No corrosive effect on instruments

Disadvantages• High temperature damages some items• Penetration of heat slow, uneven

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Ethylene Oxide (EO)

• Colourless, flammable, explosive and toxic gas • Processing cycles overnight or longer• Parametric release is not possible

• EO and relative humidity cannot readily be measured

• Spores of Bacillus atrophaeus used as biological indicators to monitor process

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Ethylene Oxide (EO) Gas Sterilisation• Used for heat or moisture sensitive

items• Prevents normal cellular metabolism

and replication

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EO Sterilisation

Advantages• Items not damaged

by heat or moisture• Not corrosive, not

damaging to delicate instruments, scopes

• Permeates porous materials

• Dissipates from material

Disadvantages• Cost• Toxic properties of

ethylene oxide• Aeration required• Longer process

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Hydrogen Peroxide Gas Plasma • Highly reactive/charged particles from

hydrogen peroxide generated under vacuum

• Can be used to sterilise heat- and moisture-sensitive items • Some plastics, electrical/electronic devices, and

corrosion-susceptible metal alloys

• Not compatible with cellulose (linen, paper), devices with dead-end lumens, powders and liquids

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Fumigation

• For rooms contaminated with some pathogens • Such as MRSA and Clostridium difficile

• Release of hydrogen peroxide, chlorine dioxide gas or possibly ozone in sealed rooms

• Spore strips (biological indicators) placed strategically to monitor process

• Special equipment required• Risk of damage to sensitive items

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Pasteurisation and Boiling

• Semi-critical items can be pasteurised • 65-77°C, 30 min• Example: respiratory therapy equipment

• Must be retrieved carefully for safe transport and storage

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Filtration

• Removal of microbes from air or heat-sensitive liquids

• Disinfectant-impregnated filters may inactivate trapped microorganisms

• Example: High-efficiency particulate air (HEPA) filters

• All filters must be checked for integrity and replaced as necessary

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Automated Endoscope Reprocessors• Alternative to manual reprocessing of

heat-sensitive devices• Minimise exposure of staff to pathogens

and disinfectants• Require access to reliable electric and

water supplies, specific chemicals, regular maintenance

• Biofilm build-up must be avoided

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Ultraviolet (UV) Light

• UV lamps useful for chemical-free disinfection of air and water and also possibly for decontamination of environmental surfaces

• Broad-spectrum microbicidal action • Require regular cleaning and periodic

replacement

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Microwaves

• Heating from rapid rotation of water molecules• Limited use except for disinfecting soft contact

lenses and urinary catheters for intermittent self-catheterisation

• May be used in emergencies to treat water for drinking or to ‘disinfect’ small water-immersible plastic or glass items

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Sterilisation Process Monitoring

Recommended practices state that both biological and chemical indicators shall be used to monitor the sterilisation process

• Mechanical monitoring

• Chemical monitoring

• Biological monitoring

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Chemical Indicators

• External Chemical Indicator• process indicator - autoclave tape• distinguishes processed from unprocessed medical

devices• secures pack• labels pack

• Check external indicator to ensure it has changed color before using any package

• If the indicator did not change, do not use56

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Biological Indicators

• Requires routine monitoring daily• Test must be dated and labeled• Once removed from the steriliser the test pack

opened, BI labeled, crushed and incubated in the incubator

• Records of time, date of incubation and staff initials is required and then time and date and initials of the staff reading the final BI result

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Biological Monitoring

• SteamGeobacillus stearothermophilus• Dry heat B.atrophaeus (formerly B.subtilis)• EO B.atrophaeus • New low temperature sterilisation technologies

• Plasma sterilisation (Sterrad) B.atrophaeus• Peracetic acid - Geobacillus stearothermophilus

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Main IP&C priorities • Development of reprocessing protocols for

instruments and equipment based on generally recognised standards and manufacturer's recommendations

• Use of clean water for cleaning items thoroughly• Maintenance, use, and monitoring of equipment,

e.g., autoclaves• Discarding items that cannot be cleaned or

reprocessed adequately• Storing reprocessed items away from potential

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References - 1• Guidelines for Environmental Infection Control in Health-

Care Facilities. MMWR 2003; 52(RR10):1-42. http://www.cdc.gov/hicpac/pdf/guidelines/eic_in_HCF_03.pdf

• Ontario Ministry of Health & Long-Term Care. Provincial Infectious Diseases Advisory Committee (PIDAC) Best Practices for Cleaning, Disinfection and Sterilization in All Health Care Settings, 2010. http://www.publichealthontario.ca/en/BrowseByTopic/InfectiousDiseases/PIDAC/Pages/PIDAC_Documents.aspx

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References - 2• Rutala WA, Weber DJ. Guideline for Disinfection and

Sterilization in Healthcare Facilities, 2008. Centers for Disease Control and Prevention, Atlanta, GA. http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf

• Snyder, OP. Calibrating thermometers in boiling water: Boiling Point / Atmospheric Pressure / Altitude Tables. http://www.hi-tm.com/Documents/Calib-boil.html

• Sattar A. Allen Denver Russell Memorial Lecture, 2006. The use of microbicides in infection control: a critical look at safety, testing and applications. J Appl Microbiol 2006; 101:743-753.

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Quiz1. Decontamination results in an item that is safe for patient

reuse. True/False.2. Disinfection:

a. Is used for items that will contact intact skinb. Involves chemical agentsc. Reduces the numbers of microorganismsd. All of the above

3. The most reliable means of sterilisation is:a. Ethylene oxideb. Steamc. Dry heatd. Plasma

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International Federation of Infection Control• IFIC’s mission is to facilitate international networking in

order to improve the prevention and control of healthcare associated infections worldwide. It is an umbrella organisation of societies and associations of healthcare professionals in infection control and related fields across the globe .

• The goal of IFIC is to minimise the risk of infection within healthcare settings through development of a network of infection control organisations for communication, consensus building, education and sharing expertise.

• For more information go to http://theific.org/

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