OBJECTIVES
1. To familiarize nurses of the recommended care and maintenance of endoscopes.
2. To identify the different aspects of endoscopes and accessories.
3. To identify the proper method of ensuring endoscopic disinfection.
Endoscopic devices
evolve constantly. Physicians, nurses, and reprocessing personnel should
be familiar with the use of and recommendations for the care and maintenance
of all endoscopes and accessories. Many costly repairs can be reduced
significantly or eliminated by mandating attendance at comprehensive
in-service programs for all personnel involved in handling and reprocessing
endoscopes.
Please keep in mind
that this article is not intended to be a substitute for the instructions
for use in the operating and maintenance manuals. Nevertheless, it will
provide a general guideline for handling and preventive maintenance
for all rigid and semi-rigid endoscopes and accessories. The manufacturer's
operating and maintenance manual should be readily available for thorough
product review and quick reference.
In rigid endoscopes,
the optical lens train transfers the viewed image to the eye of the
user or to the video monitor. This lens train comprises precisely-aligned
glass lenses and spacers (see figure 1 below). The ability to see the
image is facilitated by transmission of light via the light cord and
power source through illumination fibers distributed around the lens
train. The best endoscopic image is provided by rigid rod lens optics.
The optical element
for rigid endoscope systems is commonly called a telescope. The telescope
is also the most expensive and fragile part of the system. Failure to
handle it appropriately will result in expensive and time-consuming
repairs. The telescope is the integral part of the system, providing
both the image and light through two distinct systems.
New technologies
have resulted in small-diameter rigid endoscopes. As the diameter decreases,
the fragility may increase due to fracturing or misalignment of the
smaller glass rods. Rigid endoscopes are less forgiving to bending or
flexing than semi-rigid or flexible endoscopes.
Care
and Handling of Telescopes
Inspect all surface
areas of the rigid endoscope for any scratches, dents, evidence of burns,
or other irregularities on a regular basis. Inspection for image clarity
can be performed by holding the tip of the endoscope approximately three
inches above a nonglaring, printed white surface. Move the tip of the
endoscope progressively closer to the printed surface until it is about
one-quarter inch away. The image should be crisp and clear, with minimal
distortion. If the image is discolored or hazy, it may be due to improper
cleaning, a disinfectant residue, a cracked or broken lens, the presence
of internal moisture, or external damage.
Inspect the optical
fibers surrounding the lens train at the tip of the endoscope by holding
the light post toward a bright light. Black dots and shadowed areas
may indicate broken, damaged, or dirty fibers, and will cause a loss
of light to be transferred. Directing the tip of the scope toward a
bright light and observing the light post can provide the same information.
Delivery
Systems
A variety of reusable
and disposable sheaths and cannulae in numerous configurations are available
for use with endoscopes. They provide access to body cavities and organs
and allow irrigation, distention, drainage, and introduction of accessories.
The following precautionary measures should be considered when using
any delivery system:
Examine tips of
reusable sheaths and cannulae prior to insertion to avoid inadvertent
patient injury.
Ensure the channel
is free of blood and debris before insertion of the endoscope.
Be aware of possible
electrosurgical hazards that may result from radio-frequency current
seeking alternative paths to ground through structures outside the viewing
area of the endoscope.
Disassemble stopcocks
and valves on reusable sheaths for cleaning, disinfecting, and sterilizing.
Bridges
and Adapters
Bridges and adapters
connect the telescope to the sheath and cannula, and allow for introduction
of accessories (with or without deflection), and the application of
electrosurgical energy to resect or coagulate tissue. Examples include
a resectoscope working element, accessory ports, reducer caps, or sleeve
used in laparoscopic procedures.
By design, the shafts
of bridges and other rigid accessories are constructed of thin metal
tubing due to size constraints. These can be dented or bent easily and
should be handled carefully. Dented instruments will not assemble properly.
Accessories
Accessories may
be reusable or disposable, and may vary in size, configuration, and
intended use. Examples include guide wires, biopsy and grasping forceps,
stone baskets, scissors, catheters or stents, and electrodes. Reusable
accessories should be checked thoroughly for function and integrity
before and after each use. (Insulation must be intact on all electrical
components.) Manufacturers are not legally responsible if an item labeled
"disposable" or "single-use only" is reused and
then malfunctions. Adhere to all manufacturers' label instructions.
Cleaning,
Disinfecting, and Sterilizing of Endoscopic Instruments
Laparoscopic hand
instruments are the biggest challenge to OR personnel today. These instruments
are extremely difficult to clean because of the long shaft and jaw assembly,
which may trap debris. The positive pressure of the insufflated abdomen,
blood, and other body fluids flow into these channels and may be difficult
or impossible to remove. Many of these instruments cannot be disassembled
to facilitate manual cleaning, and ultrasonic cleaning systems may be
contraindicated due to the small joints and jaws.
These instruments
should be wiped frequently to remove any visible soil, and should be
immersed in an enzymatic cleaning solution immediately following a procedure
to initiate the decontamination procedure. Channels should be flushed
copiously and jaws should be brushed vigorously.
The initial and
most important step of reprocessing is thorough cleaning to remove gross
soil, including microorganisms (bioburden), which allows the disinfectant
or sterilizing agents to work effectively. Organic materials may inactivate
these agents or present a barrier that prevents disinfectants from reaching
all surfaces of an instrument. Manual cleaning is the safest method
to use for rigid and single-lumen flexible endoscopes and accessories.
Ultrasonic washers can damage and loosen small joints and remove adhesives
and lubricants. The mechanical washer/disinfectors designed for flexible
GI scopes commonly generate pressures too high for the smaller lumens
common to flexible endoscopes used in urology and gynecology.
The revised OSHA
Bloodborne Pathogen Standard should be referred to when manually cleaning
instruments. Proper personal protective equipment (PPE) should be worn.
This includes an impervious gown or apron, heavy-duty gloves, and eye
protection to avoid splatters from lumen brushes. Both the external
and internal (lumen) surfaces of endoscopic instruments must be cleaned.
Refer to the endoscope manufacturer's manual for appropriate cleaning
instructions.
Manual cleaners
must be evaluated for their ability to remove organic soils. Dish detergents
and skin cleansers are not recommended, as they may not effectively
remove organic soils and may actually leave a residue on the instruments
that may inhibit the subsequent disinfection or sterilization process.
Enzymatic detergents are excellent choices for cleaning endoscopic instruments.
The enzymes used in these detergents are specific to protein, sugar,
or fat. Choose an enzyme detergent that is effective for the materials
and solutions to which the instrument is exposed. Refer to the manufacturer's
label for use instructions, including temperature of the water used
to prepare the detergent. If an instrument is not cleaned properly,
it cannot be sterilized or disinfected.
Sterilization
Steam is the most
common and least expensive method of sterilization. However, many lensed
endoscopic instruments cannot be steam sterilized. Even instruments
and telescopes marketed as "autoclavable" will last longer
if processed by alternative methods.
Ethylene oxide gas
has been the standard for sterilizing heat-sensitive items, including
endoscopes. Sterilization cycles are typically one and one-half to two
hours at 55(C. Items must then be aerated mechanically for eight to
12 hours. Ethylene oxide (EO) is being gradually replaced in some hospitals
with other sterilization methods, such as steam, vapor-phase methods,
and paracetic acid because of cost and safety concerns. However, caution
should exercised before eliminating EO, since some of the alternatives
have significant processing limitations and materials compatibility
issues, including device lumen size (that can be sterilized) or lack
of storage life of the devices (just-in-time sterilization). The Steris
System (Steris, Mentor, Ohio) uses peracetic acid in a proprietary liquid
processor to sterilize items in less than 30 minutes at 50-55(C. This
method is a just-in-time process and sterility cannot be maintained
for long term storage.
Plasma and/or vapor
phase are another sterilization modality for endoscopic instruments.
Sterrad (Advanced Sterilization Processes of Irvine, Calif.) is FDA-approved
for use in the US. Check with the company for restrictions on lumen
sizes which have been approved.
Disinfection
If sterilization
is not possible, high-level disinfection is recommended for patient-care
items that come in contact with mucous membranes. High-level disinfectants
are sporicidal, bactericidal, virucidal, and fungicidal agents that
remove most bioburden, with the exception of some spores. The FDA regulates
the label claims as they pertain to the use of the product to disinfect
medical instrumentation, particularly the time required to kill specified
organisms.
Commercial preparations
of glutaraldehyde are available in both alkaline and acidic formulations.
Although the slightly acidic preparations appear to be safe for endoscopic
instrumentation, alkaline preparations are more common. The solutions
are available in 2.4% or 3.5% concentrations. The 2.4% concentrations
without surfactants are the recommended solutions for endoscopic instruments.
Surfactants serve as wetting agents to reduce surface tension and allow
the disinfecting solution to penetrate areas that water is unable to
reach. However, surfactants may leave a residue that is electrically
conductive, difficult to rinse off, and may prohibit small joints from
moving freely.
Removing all traces
of disinfectant by rinsing the instruments is extremely important. Glutaraldehyde
is very caustic to skin and mucous membranes and could contribute to
chemical burns. Glutaraldehyde manufacturers are now recommending three
separate, sterile rinses of at least one minute each. The rinse water
is not to be reused. Please refer to the glutaraldehyde package inserts
for specific instructions on use, reuse, rinsing, and disposal.
More information
about glutaraldehyde is available from the manufacturers in their product
inserts. Pay careful attention to the labels on all products to reduce
the possibility of damage to your instrumentation, and injuries to your
patients and yourself. Be sure cleaning products are compatible with
the disinfectant or sterilizing agent. Avoid the use of highly alkaline
or highly acidic cleaners as they may damage the instruments. Refer
to the instrument manufacturers' manuals for use, especially regarding
cleaning, disinfection, sterilization, handling, and storage. Proper
handling and storage can eliminate many costly repairs.
Conclusion
Reusable endoscopic
instruments can be reprocessed safely and effectively, providing they
are cleaned and sterilized or disinfected according to the manufacturers'
recommendations. All cleaning, disinfecting and sterilizing processes
must be standardized and monitored to ensure process quality. Refer
to the instrument and chemical manufacturers' written instructions for
compatibility and usage. Establish specific policies and procedures
to ensure proper handling and standardized practices.
Eileen Young is
a gynecology clinical specialist at Circon Corporation in Stamford,
Conn.
References:
1. Endoscopes: Tough problems with their cleaning and reprocessing.
OR Manager. 1990;6:1-7.
2. Garner JS, Favero MS. Guidelines for handwashing and hospital environmental
control. Am J Infect Control. 1985;14:110-126.
3. Good hospital practice: Handling and biological decontamination of
reusable medical devices (American National Standard) designation. Arlington,
VA; Association for the Advancement of Medical Instrumentation, 1992;669-690.
4. Milner NA. A system approach to patient-safe rigid and flexible endoscopes:
A microbiologist's point of view. J Healthcare Material Management.1992;10:3.
Young EC. A disinfectant guide. Urologic Nursing. 1990;9-7.
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