What's Lurking in Your Endoscope?

May 1, 2003

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

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

Mycobacterium tuberculosis
Atypical mycobacteria

Trichrosporon sp
Rhodotorula rubra


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 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 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

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.


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

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

The facility should carries 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


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).