sterilization of

STERILIZATIONSTERILIZATION ofof ENDOSCOPESENDOSCOPES

Dr.T.V.Rao MDDr.T.V.Rao MD

Endoscopes and InfectionEndoscopes and Infection

Physicians use endoscopes to diagnose and treat numerous medical disorders. Even though endoscopes represent a valuable diagnostic and therapeutic tool in modern medicine and the incidence of infection associated with their use reportedly is very low (about 1 in 1.8 million procedures) 97, more healthcare–associated outbreaks have been linked to contaminated endoscopes than to any other medical device.

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Dealing with heat senstive Dealing with heat senstive EndoscopesEndoscopes

To prevent the spread of health-care–associated infections, all heat-sensitive endoscopes (e.g., gastrointestinal endoscopes, bronchoscopes, nasopharygoscopes) must be properly cleaned and, at a minimum, subjected to high-level disinfection after each use. High-level disinfection can be expected to destroy all microorganisms, although when high numbers of bacterial spores are present, a few spores might survive.


Uses of Flexible EndoscopesUses of Flexible Endoscopes

Flexible fiber optic or Flexible fiber optic or video endoscope used video endoscope used in the examination of in the examination of the hollow viscera the hollow viscera (i.e. colonoscope, (i.e. colonoscope, gastroscope, gastroscope, duodenoscope, duodenoscope, sigmoidoscope, sigmoidoscope, bronchoscope).bronchoscope).

Why sterilizing EndoscopesWhy sterilizing Endoscopes Endoscopes are Endoscopes are

routinely exposed to routinely exposed to mucus and other mucus and other gastrointestinal gastrointestinal secretions, blood, secretions, blood, saliva, faeces, bile, saliva, faeces, bile, and sometimes pus. and sometimes pus. The process of The process of decontamination decontamination comprises two basic comprises two basic components:components:

Endoscopes are used in Endoscopes are used in Invasive proceduresInvasive procedures

Endoscopes are classified as semi critical Endoscopes are classified as semi critical instruments; if they enter sterile body instruments; if they enter sterile body cavities, they are critical equipment. cavities, they are critical equipment. Certainly some endoscopic accessories are Certainly some endoscopic accessories are considered critical -- sclerotherapy needles considered critical -- sclerotherapy needles and cutting forceps are two named in the and cutting forceps are two named in the AJIC article. AJIC article.

Basic cleaning of EndoscopesBasic cleaning of Endoscopes

Manual cleaning, which includes brushing Manual cleaning, which includes brushing with single-use wire brushes, and with single-use wire brushes, and exposure of all external and accessible exposure of all external and accessible internal components to a low-foaming internal components to a low-foaming enzymatic detergent known to be enzymatic detergent known to be compatible with the endoscope;compatible with the endoscope;

Automatic disinfection, rinsing and dryingAutomatic disinfection, rinsing and drying of all exposed surfaces of the endoscopeof all exposed surfaces of the endoscope

Dealing with EndoscopesDealing with Endoscopes Semi critical items contact mucous membranes

or no intact skin. This category includes respiratory therapy and anaesthesia equipment, some endoscopes, laryngoscope blades , oesophageal manometer probes, cyst scopes, anorectic manometer catheters, and diaphragm fitting rings. These medical devices should be free from all microorganisms; however, small numbers of bacterial spores are permissible.


Dealing with EndoscopesDealing with Endoscopes Intact mucous

membranes, such as those of the lungs and the gastrointestinal tract, generally are resistant to infection by common bacterial spores but susceptible to other organisms, such as bacteria, mycobacteria, and viruses


Chemical Methods of Chemical Methods of sterilizationsterilization

FDA cleared agentsFDA cleared agents

Glutaraldehyde, hydrogen peroxide, ortho-phthalaldehyde, and per acetic acid with hydrogen peroxide are cleared by the Food and Drug Administration (FDA) and are dependable high-level disinfectants provided the factors influencing germicidal procedures are met.


Decontamination of Decontamination of EndoscopesEndoscopes

Decontamination of endoscopes should be Decontamination of endoscopes should be undertaken at the beginning and the end undertaken at the beginning and the end of each list, and between patients, by of each list, and between patients, by trained staff in dedicated rooms. trained staff in dedicated rooms. Thorough manual cleaning with an Thorough manual cleaning with an enzymatic detergent, including the enzymatic detergent, including the brushing of all accessible endoscope brushing of all accessible endoscope channels, must be undertaken before channels, must be undertaken before automatic endoscope disinfection.automatic endoscope disinfection.


Minimal requirementsMinimal requirements

All disinfectants should be used at All disinfectants should be used at the correct temperature in the correct temperature in accordance with the manufacturers’ accordance with the manufacturers’ instructions. Some manufacturers instructions. Some manufacturers provide test strips and/or kits, the use provide test strips and/or kits, the use of which they recommend in ensuring of which they recommend in ensuring optimal activity of their product.optimal activity of their product.


The Ideal disinfectant ?The Ideal disinfectant ?

Effective against a wide range of organisms Effective against a wide range of organisms including blood-borne viruses and Prions including blood-borne viruses and Prions proteins.proteins.

Compatible with endoscopes, accessories and Compatible with endoscopes, accessories and endoscope reprocesses.endoscope reprocesses.

Non-irritant and safe for users.Non-irritant and safe for users. Environmentally friendly Environmentally friendly However yet no totally safe chemical available.However yet no totally safe chemical available.


Ethylene OxideEthylene Oxide Ethylene oxide gas has been the standard for Ethylene oxide gas has been the standard for

sterilizing heat-sensitive items, including sterilizing heat-sensitive items, including endoscopes. Sterilization cycles are typically one endoscopes. Sterilization cycles are typically one and one-half to two hours at 55°C. Items must and one-half to two hours at 55°C. Items must then be aerated mechanically for eight to 12 then be aerated mechanically for eight to 12 hours. Ethylene oxide (EO) is being gradually hours. Ethylene oxide (EO) is being gradually replaced in some hospitals with other replaced in some hospitals with other sterilization methods, such as steam, vapor-sterilization methods, such as steam, vapor-phase methods and par acetic acid because of phase methods and par acetic acid because of cost and safety concerns. However, caution cost and safety concerns. However, caution should exercised before eliminating EO, should exercised before eliminating EO,

Ethylene OxideEthylene OxideA safety concernA safety concern

Ethylene oxide Ethylene oxide (EtO)(EtO) gas sterilizers have been gas sterilizers have been used by hospitals for over 40 years to sterilize used by hospitals for over 40 years to sterilize surgical equipment and supplies that are heat surgical equipment and supplies that are heat sensitive or that cannot tolerate excessive sensitive or that cannot tolerate excessive moisture. However, in recent decades, EtO has moisture. However, in recent decades, EtO has been recognized as a potential mutagenic, been recognized as a potential mutagenic, reproductive, neurological, and fire and reproductive, neurological, and fire and explosion hazard to workers, and one agency explosion hazard to workers, and one agency has reportedly voted to classify EtO as has reportedly voted to classify EtO as carcinogenic to humans. carcinogenic to humans.

OSHA regulates Use of Ethylene OxideOSHA regulates Use of Ethylene Oxide

Strict regulations Strict regulations concerning concerning EtOEtO exposure have exposure have been imposed by been imposed by the Occupational the Occupational Safety and Health Safety and Health Administration Administration (OSHA), (OSHA),

Use of AldehydesUse of Aldehydes It should be emphasised that aldehydes, such as It should be emphasised that aldehydes, such as

ortho-phthalaldehyde and glutaraldehydeortho-phthalaldehyde and glutaraldehyde, , fix protein, a property which may not only fix protein, a property which may not only stabilise prion infectivity, but also render it more stabilise prion infectivity, but also render it more difficult to remove by other means. difficult to remove by other means. Aldehydes Aldehydes should never be used for disinfection until should never be used for disinfection until the equipment has been thoroughly the equipment has been thoroughly cleaned, with all accessory channels cleaned, with all accessory channels manually brushed, washed with enzymatic manually brushed, washed with enzymatic detergent and rinsed with water.detergent and rinsed with water.


GlutaraldehydeGlutaraldehyde Glutaraldehyde should be in contact with all Glutaraldehyde should be in contact with all

internal and external surfaces and channels of internal and external surfaces and channels of the device for at least 20 minutes. Since it is an the device for at least 20 minutes. Since it is an irritant, the following measures should be irritant, the following measures should be considered to ensure safer working conditions considered to ensure safer working conditions (superior ventilation) for reprocessing staff: (superior ventilation) for reprocessing staff: "ducted exhaust hoods, air systems that provide "ducted exhaust hoods, air systems that provide seven to 15 air exchanges per hour, ductless seven to 15 air exchanges per hour, ductless fume hoods with absorbents for the vapour, fume hoods with absorbents for the vapour, tight fitting lids on immersion baths, and tight fitting lids on immersion baths, and automated endoscope processors." automated endoscope processors."

Effectiveness of Effectiveness of GlutarladehydeGlutarladehyde

The FDA label claim for high-level disinfection with greater than 2% glutaraldehyde at 25°C ranges from 20 to 90 minutes depending on the product. However, multiple scientific studies and professional organizations support the efficacy of greater than 2% glutaraldehyde at 20 minutes at 20°C

Hydrogen PeroxideHydrogen Peroxide Although hydrogen peroxide can damage rubber Although hydrogen peroxide can damage rubber

and plastics and corrode copper, zinc and brass, and plastics and corrode copper, zinc and brass, it is suitable for endoscope reprocessing as long it is suitable for endoscope reprocessing as long as it is not contraindicated in the endoscope as it is not contraindicated in the endoscope reprocessing instructions. The solution to be reprocessing instructions. The solution to be used should be 7.5 percent hydrogen peroxide used should be 7.5 percent hydrogen peroxide and 0.85 percent phosphoric acid. and 0.85 percent phosphoric acid.


Peracetic acidPeracetic acid

Peracetic acid is connected to several Peracetic acid is connected to several health hazards, including severe burns health hazards, including severe burns (from direct skin contact), irreversible (from direct skin contact), irreversible damage or blindness (from direct contact damage or blindness (from direct contact with the eyes), and irritation of the nose, with the eyes), and irritation of the nose, throat and lungs (from inhalation of the throat and lungs (from inhalation of the per acetic acid vapor). per acetic acid vapor).

However the compound found to be useful However the compound found to be useful in decontamination of endoscopes.in decontamination of endoscopes.

Peracetic acid with hydrogen Peracetic acid with hydrogen peroxideperoxide

The combination The combination of these agents of these agents has been has been approved by the approved by the FDA for FDA for sterilizing semi sterilizing semi critical medical critical medical devices devices


OrthophalaldehydeOrthophalaldehyde

Orthophalaldehyde apparently has several Orthophalaldehyde apparently has several advantages over glutaraldehyde; it has advantages over glutaraldehyde; it has "excellent stability over a wide pH range "excellent stability over a wide pH range of 3-9" and does not irritate the eyes or of 3-9" and does not irritate the eyes or nasal passages, and it does not require nasal passages, and it does not require activation before use. activation before use.

Emerging chemical agentsEmerging chemical agents Super oxidized water is the aqueous solution Super oxidized water is the aqueous solution

which is produced in the anode side by which is produced in the anode side by electrolysis of sodium chloride or potassium electrolysis of sodium chloride or potassium chloride added to the water and shows strong chloride added to the water and shows strong sterilization action. The super oxidized water is a sterilization action. The super oxidized water is a powerful disinfectant which follows powerful disinfectant which follows glutaraldehyde, and it is effective for nutrition glutaraldehyde, and it is effective for nutrition bacteria, MRSA, general viruses and other bacteria, MRSA, general viruses and other microbes. There is no resistant microbe against microbes. There is no resistant microbe against the super oxidized water. The super oxidized the super oxidized water. The super oxidized water is safe to the human body. water is safe to the human body.


Super Oxidized water in Super Oxidized water in sterilizationsterilization

Super-oxidized water” – Super-oxidized water” – also known as anolyte – also known as anolyte – is water that has had an is water that has had an electric current passed electric current passed through it, thereby through it, thereby generating a number of generating a number of oxidized species. This is oxidized species. This is an electrochemical (or an electrochemical (or oxidation-reduction) oxidation-reduction) process. Specifically, it is process. Specifically, it is an electrolysis process. an electrolysis process.

Super-oxidized waterSuper-oxidized water In recent years, neutral In recent years, neutral

electrolyzed water electrolyzed water ('NEW') has been ('NEW') has been developed as a high-level developed as a high-level non-corrosive non-corrosive disinfectant, able to disinfectant, able to penetrate cell membranes penetrate cell membranes more effectively in more effectively in comparison with acidic comparison with acidic electrolyzed water electrolyzed water ('AEW') or Sodium ('AEW') or Sodium Hypochlorite or other Hypochlorite or other traditional chemical traditional chemical disinfectants. disinfectants.


High level disinfectionHigh level disinfection

The FDA definition of high-level disinfection is a sterilant used for a shorter contact time to achieve a 6-log10 kill of an appropriate Mycobacterium species. Cleaning followed by high-level disinfection should eliminate enough pathogens to prevent transmission of infection.

Physical exposure too is Physical exposure too is importantimportant

Completely immerse the endoscope and its components in the high-level disinfectant/sterilant and ensure that all channels are perfused. Nonimmersible gastrointestinal endoscopes should be phased out immediately.

Final removal of disinfectant Final removal of disinfectant after disinfection.after disinfection.

After high-level disinfection, rinse the endoscope and flush the channels with sterile, filtered, or tap water to remove the disinfectant. Discard the rinse water after each use/cycle. Flush the channels with 70% to 90% isopropyl alcohol.

STERIS® from Steris STERIS® from Steris CorporationCorporation

STERIS® is a "cold" liquid sterilization. STERIS® is a "cold" liquid sterilization. Acetic peroxide is mixed with sterile water; Acetic peroxide is mixed with sterile water; the instruments to be sterilized are the instruments to be sterilized are washed with solvents. After twelve washed with solvents. After twelve minutes of dipping the instrument in the minutes of dipping the instrument in the sterilizing solution, the solution is sterilizing solution, the solution is pumped out and the instrument is rinsed pumped out and the instrument is rinsed with sterile water four times with sterile water four times


STERIS® from Steris STERIS® from Steris CorporationCorporation

The working channel of rigid / flexible The working channel of rigid / flexible endoscopes can be attached to a endoscopes can be attached to a pressurized fitting for sterilization. The pressurized fitting for sterilization. The mixture of water and acetic peroxide is mixture of water and acetic peroxide is controlled during the dipping procedure controlled during the dipping procedure with recording concentration and with recording concentration and temperature increasing to 50 0C (122 0F) temperature increasing to 50 0C (122 0F) - 55.5 0C (131.9 0F) . - 55.5 0C (131.9 0F) .

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Ortho-phthalaldehyde: a New Ortho-phthalaldehyde: a New Chemical SterilantChemical Sterilant

Ortho-phthalaldehyde (OPA) received clearance by FDA Ortho-phthalaldehyde (OPA) received clearance by FDA in October 1999. OPA solution is a clear, pale-blue liquid in October 1999. OPA solution is a clear, pale-blue liquid (pH, 7.5), which typically contains 0.55% OPA. OPA has (pH, 7.5), which typically contains 0.55% OPA. OPA has demonstrated excellent microbiocidal activity in in vitro demonstrated excellent microbiocidal activity in in vitro studies For example, it has shown superior studies For example, it has shown superior mycobactericidal activity (5-log10 reduction in 5 mycobactericidal activity (5-log10 reduction in 5 minutes) compared with Glutaraldehyde. The mean time minutes) compared with Glutaraldehyde. The mean time required to effect a 6-log10 reduction for required to effect a 6-log10 reduction for M. bovisM. bovis using using 0.21% OPA was 6 minutes, compared with 32 minutes 0.21% OPA was 6 minutes, compared with 32 minutes using 1.5% glutaraldehyde using 1.5% glutaraldehyde


Ortho-phthalaldehyde: a New Ortho-phthalaldehyde: a New Chemical SterilantChemical Sterilant

When tested against a wide range of When tested against a wide range of microorganisms, including glutaraldehyde-microorganisms, including glutaraldehyde-resistant mycobacteria and resistant mycobacteria and Bacillus subtilisBacillus subtilis spores , OPA showed good activity against the spores , OPA showed good activity against the mycobacteria tested, including the mycobacteria tested, including the glutaraldehyde-resistant strains, but 0.5% OPA glutaraldehyde-resistant strains, but 0.5% OPA was not sporicidal within 270 minutes of was not sporicidal within 270 minutes of exposure. Increasing the pH from its unadjusted exposure. Increasing the pH from its unadjusted level (about 6.5) to pH 8 improved sporicidal level (about 6.5) to pH 8 improved sporicidal activity. activity.


Emerging MethodsEmerging Methods Other agents Other agents

currently being currently being investigated for investigated for efficacy in sterilization efficacy in sterilization and disinfection and disinfection include chlorine include chlorine dioxide, ozone, vapor-dioxide, ozone, vapor-phase phase hydrogen hydrogen peroxide and peroxide and plasma technology.plasma technology.


Emerging Technology – Gas Emerging Technology – Gas PlasmaPlasma

Low-temperature Low-temperature hydrogen peroxide gas hydrogen peroxide gas plasma has also made its plasma has also made its mark on device mark on device manufacturers for manufacturers for sterilizing temperature-sterilizing temperature-sensitive polymeric sensitive polymeric materials. This method materials. This method offers rapid turnaround offers rapid turnaround time, in-house control of time, in-house control of the sterilization process, the sterilization process, and lower inventory and lower inventory requirements. requirements.

Sterilization of autoclavable Sterilization of autoclavable Endoscopes Endoscopes

Prepare the Endoscope by washing the outside Prepare the Endoscope by washing the outside with mild soap and warm water. Approved with mild soap and warm water. Approved instrument wraps should be folded around the instrument wraps should be folded around the Scope and it should be placed in an approved Scope and it should be placed in an approved sterilizer tray on a soft surface. sterilizer tray on a soft surface.

The instrument should be autoclaved.The instrument should be autoclaved. At present few endoscopes can be sterilized by At present few endoscopes can be sterilized by

heat ( Autoclaving )heat ( Autoclaving )

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Testing the sterilization Testing the sterilization activityactivity

Perform routine testing of the liquidsterilant/high-level disinfectant to ensure minimal effective concentration of the active ingredient. Check the solution at the beginning of each day of use (or more frequently) and document the results. If the chemical indicator shows that the concentration is less than the minimal effective concentration, the solution should be discarded. CategoryIA

Health care workers should Health care workers should follow standard guidelinesfollow standard guidelines

All healthcare personnel in the endoscope suite should be trained in and adhere to standard infection control recommendations (eg, standard precautions), including those to protect both patients and healthcare workers.Category IA9

Keep a Log for accountability Keep a Log for accountability of Transmission of Infectionsof Transmission of Infections

A record should be A record should be kept of the serial kept of the serial number of each number of each endoscope used in endoscope used in each patient. This is each patient. This is important for any important for any future contact tracing future contact tracing when possible when possible endoscope endoscope transmission of transmission of disease is being disease is being investigated.investigated.

Endoscopy staff – Occupational Endoscopy staff – Occupational SafetySafety

Endoscopy staff should be educated regarding Endoscopy staff should be educated regarding hazards associated with performing/assisting hazards associated with performing/assisting with endoscopies and with reprocessing. They with endoscopies and with reprocessing. They should be trained regarding the Occupational should be trained regarding the Occupational Safety and Health Administration Safety and Health Administration (OSHA)s(OSHA)s hazardous communications standard, and should hazardous communications standard, and should have access to a spill containment plan pertinent have access to a spill containment plan pertinent to the sterilant or disinfectant being used when to the sterilant or disinfectant being used when reprocessing occurs. reprocessing occurs.


Protection against the Protection against the Chemical disinfectantsChemical disinfectants..

All personnel using chemicals should be educated about the biological and chemical hazards present while performing procedures that use disinfectants.


Decontaminating Decontaminating vCJDvCJD At present conventional At present conventional

sterilisation methods sterilisation methods cannot reliably destroy cannot reliably destroy PrPsc, the infecting agent PrPsc, the infecting agent in vCJD, but the in vCJD, but the likelihood of equipment likelihood of equipment becoming contaminated becoming contaminated with infective tissue is with infective tissue is small. Rigorous cleaning small. Rigorous cleaning techniques will reduce the techniques will reduce the risk even further. risk even further.


Routine Methods not effective Routine Methods not effective in decontamination of vCJDin decontamination of vCJD

Putative infecting agent in vCJD cannot be removed or destroyed by conventional sterilisation or decontamination methods.

Emerging methods to sterilize Emerging methods to sterilize CJDCJD

ERI's new process, or MIDAS, will effectively ERI's new process, or MIDAS, will effectively reduce the incidence of CJD infection and reduce the incidence of CJD infection and number of operations cancelled due to number of operations cancelled due to contaminated instruments, according to ERI contaminated instruments, according to ERI researchers. The team at ERI also reports that researchers. The team at ERI also reports that their studies demonstrate that the MIDAS their studies demonstrate that the MIDAS process is at least 1,000 times more effective process is at least 1,000 times more effective than traditional cleaning methods and does not than traditional cleaning methods and does not damage surgical instruments. damage surgical instruments.


Compliance reduces Compliance reduces transmission of Infectionstransmission of Infections

Compliance with accepted guidelines for the reprocessing of gastrointestinal endoscopes between patients is critical to the safety and success of their use. When these guidelines are followed, pathogen transmission can be effectively prevented.


Created for Awarness to Medical and Created for Awarness to Medical and Paramedical staff in Developing Paramedical staff in Developing

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