What's Lurking in Your Endoscope?


What's Lurking in Your Endoscope?

By Kathy Dix

We all know how important it is to clean instruments before theyare re-used on patients. Endoscopy equipment in particular can be challenging toclean.

Highly-publicized accounts of poorly cleaned endoscopy equipmentmade the rounds in early 2002. Patients at Johns Hopkins Medical Center andNashville's Skyline Hospital sickened and died from pathogens they had beenexposed to during bronchoscopy. By the time the outbreak was checked, two JohnsHopkins patients had died and 100 patients (of 415 exposed) had tested positivefor Pseudomonas aeruginosa.

But P. aeruginosa is not the only pathogen lurking in endoscopes' nooks andcrannies. Other infectious microorganisms lie in wait for the faulty sterilizeror hasty cleaning. These can include:

Gram-negative bacilli

Pseudomonas aeruginosa
Klebsiella sp
Enterobacter sp
Serratia marcesans
Salmonella sp incl typhi
Heliobacter pylori
Bacillus sp
Proteus sp

Mycobacterium tuberculosis
Atypical mycobacteria

Trichrosporon sp
Rhodotorula rubra


Hepatitis B
Hepatitis C1

Endogenous and exogenous microbes can be responsible for infections relatedto endoscopy. Endogenous infections are caused by microflora of thegastrointestinal or respiratory tracts entering the bloodstream or other sterilesites within the body. According to Association for Professionals in InfectionControl and Epidemiology (APIC) guidelines, endogenous infections can include:

  • Cholangitis (from manipulation of an obstructed biliary tract)

  • Pneumonia (from aspiration of oral secretions)

  • Endocarditis (from bacteremia)

Exogenous infections can be due to:

  • Poor manual cleaning

  • Insufficient exposure of surfaces to disinfectants

  • Insufficient rinsing/drying

  • Use of automated reprocessors

There are plenty of places for pathogens to hide. Non-tuberculousmycobacteria can exist in tap water, ice and other omnipresent sources. It iscrucial that hospitals disinfect endoscopes of even these mycobacteria, as theycan easily cause infections in patients who are immunocompromised -- who make upa goodly percentage of people undergoing endoscopic procedures.

It is worth reiterating which types of scopes and procedures meritsterilization rather than high-level disinfection. All "criticaldevices" should undergo sterilization; these include any devices that entersterile tissue or body spaces. High-level disinfection at the least --sterilization is (obviously) better -- should be used for semicritical devices;these include instruments that enter mucous membranes or nonintact skin.Disinfection with an intermediate or low-level germicide, or cleaning withdetergent and water, should be used for noncritical devices -- those thatcontact intact skin.

Endoscopes are classified as semicritical instruments; if they enter sterilebody cavities, they are critical equipment. Certainly some endoscopicaccessories are considered critical -- sclerotherapy needles and cutting forcepsare two named in the AJIC article.

High-level disinfection should use any of the following disinfectants:

1. Glutaraldehyde

Glutaraldehyde should be in contact with all internal and external surfacesand channels of the device for at least 20 minutes. Since it is an irritant, thefollowing measures should be considered to ensure safer working conditions(superior ventilation) for reprocessing staff: "ducted exhaust hoods, airsystems that provide seven to 15 air exchanges per hour, ductless fume hoodswith absorbents for the vapor, tight fitting lids on immersion baths, andautomated endoscope processors."

2. Hydrogen peroxide

Although hydrogen peroxide can damage rubber and plastics and corrode copper,zinc and brass, it is suitable for endoscope reprocessing as long as it is notcontraindicated in the endoscope reprocessing instructions. The solution to beused should be 7.5 percent glutaraldehyde and 0.85 percent phosphoric acid.

3. Peracetic acid

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

4. Peracetic acid with hydrogen peroxide

The combination of these agents has been approved by the FDA for sterilizingsemicritical medical devices.

5. Orthophalaldehyde

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

6. Super-oxidized water

In Sept. 2002, Sterilox's super-oxidized water was approved by the FDA forhigh-level disinfection.

Other agents currently being investigated for efficacy in sterilization anddisinfection include chlorine dioxide, ozone, vapor-phase hydrogen peroxide andplasma technology.

Certain substances are not recommended for disinfection; these include anyagent not cleared by the FDA for such use, skin antiseptics (e.g., povidone-iodine,chlorhexidine gluconate), hypochlorite, quaternary ammonium compounds, phenolics.


After the endoscope is disinfected, it should be rinsed with sterile water orwith an alcohol rinse. If an endoscope is critical equipment, only sterile watershould be used for rinsing. Complete drying is a necessity. The endoscope mustthen be properly stored.

Federal law -- the Hazard Communication Standard -- requires that theendoscopy area be provided with a written hazard communication program, a hazardevaluation, a hazardous materials inventory, material safety data sheets, labelson containers with hazardous materials and employee training.

Endoscopes should be scrupulously cleaned, tested for leaks before immersion,sterilized or high-level disinfected with an FDA-approved agent and according tothe manufacturer's instructions, rinsed, completely dried and stored properly.Reprocessing staff must receive detailed instructions regarding reprocessing ofeach specific device.

Accessories that infiltrate mucosal barriers should be mechanically cleanedand then steam sterilized. Water bottles should be filled with sterile water. Alog should be kept of every procedure, patient and medical record number,procedure, endoscopist and the endoscope's serial number or other identificationnumber.

If an infection does occur in an endoscopy patient, it should be reported tothe facility's infection control and risk management personnel, to the FDA, thestate health department, the CDC and the manufacturer.

Endoscopy staff should be educated regarding hazards associated withperforming/assisting with endoscopies and with reprocessing. They should betrained regarding the Occupational Safety and Health Administration (OSHA)'shazardous communications standard, and should have access to a spill containmentplan pertinent to the sterilant or disinfectant being used when reprocessingoccurs.

The facility should carries out routine testing of sterilants anddisinfectants to ensure that there is a "minimal effective concentration ofthe active ingredient."

It is crucial to remember that the sterilization is only as good as thesterilizer itself. Regular maintenance recommended by the manufacturer should beprovided when it is suggested. If the manufacturer suggests regular check-ups ofthe sterilizer's effectiveness, those should also be performed without delay.

Protection of reprocessing staff is just as important as protection of thepatient. Anyone who comes in contact with reprocessing chemicals should beadvised of the associated risks and how to manage spills of the reprocessingagents. Areas of endoscopy should offer not just the spill containment plan, butalso an assessment of spills, proper personal protective equipment, cleanupsupplies, and information on how to notify emergency responders such as thefacility's chemical hazard response team or safety department, or the local firedepartment's hazardous materials department.

There is no alternative to following the manufacturer's instructions forendoscope cleaning and sterilization. Those guidelines are non-negotiable.Regardless of how much time is scheduled between procedures, or how manypatients are backed up waiting, the directions are inflexible. Ultimately, thegoal is safe patient care, not faster procedures.

Since the outbreaks at Johns Hopkins and Skyline Hospital, rumblings havebeen heard suggesting that endoscope sterilization guidelines are not rigorousenough. But some experts disagree.

"New and improved endoscope reprocessing guidelines are notneeded," writes Lawrence Muscarella, PhD, editor of The Q-Net Monthly andchief of infection control at Custom Ultrasonics, Inc. "Rather, what isneeded is strict adherence to the guidelines already published and currently inplace." Muscarella stresses that complying with the guidelines -- whichrecommend cleaning every channel and surface of the endoscope, even if they havenot been used -- should ensure proper sterilization.2


Reprocessing -- not just of endoscopes, but of all medical devices deemed reprocess-able -- has been a point of contention for years. Original equipment manufacturers (OEMs) and third-party reprocessors have spent countless hours debating the merits of reprocessed versus single-use instruments and devices.

On Oct. 26, 2002, Congress passed the Medical Device User Fee and Modernization Act, public law 107-250. The law, among other provisions, allows for user fees for premarket reviews (much like those fees associated with new drug applications), establishment inspections conducted by third parties, and new regulatory requirements for reprocessed devices. This latter provision requires the submission of additional data on reprocessed devices, as well as a premarket report.

OEMs contend that single-use devices (SUDs) -- discarded without reprocessing or a second use -- ensure safety and efficacy, because improperly reprocessed devices can harbor pathogens. Reprocessors claim that OEMs are simply calling devices "single-use" in order to boost (or maintain) profits. They insist that "new" is not always better.

What it boils down to is this: if the device can be safely reprocessed, then why not reprocess it? Such devices must be able to be cleaned thoroughly, sterilized to "acceptable standards", and still function as intended. In an era of cost-consciousness -- and an era during which patients are becoming increasingly more responsible for their own care -- reprocessing should be offered as an option if it is safe (first and foremost) and if it is fiscally responsible (a consideration always secondary to safety).

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