What's Lurking in Your Endoscope?

By Kathy Dix

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

Highly-publicized accounts of poorly-cleaned endoscopy equipment made the rounds in early 2002. Patients at Johns Hopkins Medical Center and Nashville's Skyline Hospital sickened and died from pathogens they had been exposed to during bronchoscopy. By the time the outbreak was checked, two Johns Hopkins patients had died and 100 patients (of 415 exposed) had tested positive for pseudomonas aeruginosa.

But P aeruginosa is not the only pathogen lurking in endoscopes' nooks and crannies. Other infectious microorganisms lie in wait for the faulty sterilizer or 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
Mycobacteria
Mycobacterium tuberculosis
Atypical mycobacteria
Fungi
Trichrosporon sp
Rhodotorula rubra
Parasites
Strongyloides
Viruses
Hepatitis B
Hepatitis C¹

Endogenous and exogenous microbes can be responsible for infections related to endoscopy. Endogenous infections are caused by microflora of the gastrointestinal or respiratory tracts entering the bloodstream or other sterile sites within the body. According to Association for Professionals in Infection Control 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-tuberculous mycobacteria can exist in tap water, ice and other omnipresent sources. It is crucial that hospitals disinfect endoscopes of even these mycobacteria, as they can easily cause infections in patients who are immunocompromised -- who make up a goodly percentage of people undergoing endoscopic procedures.

It is worth reiterating which types of scopes and procedures merit sterilization rather than high-level disinfection. All "critical devices" should undergo sterilization; these include any devices that enter sterile 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 with detergent and water, should be used for noncritical devices -- those that contact intact skin.

Endoscopes are classified as semicritical instruments; if they enter sterile body cavities, they are critical equipment. Certainly some endoscopic accessories are considered critical -- sclerotherapy needles and cutting forceps are 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 surfaces and channels of the device for at least 20 minutes. Since it is an irritant, the following measures should be considered to ensure safer working conditions (superior ventilation) for reprocessing staff: "ducted exhaust hoods, air systems that provide seven to 15 air exchanges per hour, ductless fume hoods with absorbents for the vapor, tight fitting lids on immersion baths, and automated 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 not contraindicated in the endoscope reprocessing instructions. The solution to be used should be 7.5 percent hydrogen peroxide 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 direct contact with the eyes), and irritation of the nose, throat and lungs (from inhalation of the peracetic acid vapor).

4. Peracetic acid with hydrogen peroxide

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

5. Orthophalaldehyde

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

6. Super-oxidized water

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

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

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

Guidelines

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

Federal law -- the Hazard Communication Standard -- requires that the endoscopy area be provided with a written hazard communication program, a hazard evaluation, a hazardous materials inventory, material safety data sheets, labels on 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 to the manufacturer's instructions, rinsed, completely dried and stored properly. Reprocessing staff must receive detailed instructions regarding reprocessing of each specific device.

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

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

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

The facility should carry out routine testing of sterilants and disinfectants to ensure that there is a "minimal effective concentration of the active ingredient."

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

Protection of reprocessing staff is just as important as protection of the patient. Anyone who comes in contact with reprocessing chemicals should be advised of the associated risks and how to manage spills of the reprocessing agents. Areas of endoscopy should offer not just the spill containment plan, but also an assessment of spills, proper personal protective equipment, cleanup supplies, and information on how to notify emergency responders such as the facility's chemical hazard response team or safety department, or the local fire department's hazardous materials department.

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

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

"New and improved endoscope reprocessing guidelines are not needed," writes Lawrence Muscarella, PhD, editor of The Q-Net Monthly and chief of infection control at Custom Ultrasonics, Inc. "Rather, what is needed is strict adherence to the guidelines already published and currently in place." Muscarella stresses that complying with the guidelines - which recommend cleaning every channel and surface of the endoscope, even if they have not been used -- should ensure proper sterilization.²

For a complete list of references, visit www.surgicenteronline.com

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