Care of Endoscopic Instrumentation

February 1, 2001

Care of Endoscopic Instrumentation

By Eileen Young, RN

Endoscopic devices evolve constantly. Physicians, nurses, andreprocessing personnel should be familiar with the use of and recommendationsfor the care and maintenance of all endoscopes and accessories. Many costlyrepairs can be reduced significantly or eliminated by mandating attendance atcomprehensive in-service programs for all personnel involved in handling andreprocessing endoscopes.

This article is not intended to be a substitute for the instructions for usein the operating and maintenance manuals. Nevertheless, it provides a generalguideline for handling and preventive maintenance for all rigid and semi-rigidendoscopes and accessories. The manufacturer's operating and maintenance manualshould be readily available for thorough product review and quick reference.

In rigid endoscopes, the optical lens train transfers the viewed image to theeye of the user or to the video monitor. This lens train comprisesprecisely-aligned glass lenses and spacers (Figure 1). The ability to seethe image is facilitated by transmission of light via the light cord and powersource through illumination fibers distributed around the lens train. The bestendoscopic image is provided by rigid rod lens optics.

The optical element for rigid endoscope systems is commonly called atelescope. The telescope is also the most expensive and fragile part of thesystem. Failure to handle it appropriately will result in expensive andtime-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 thediameter decreases, the fragility may increase due to fracturing or misalignmentof the smaller glass rods. Rigid endoscopes are less forgiving to bending orflexing 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 forimage clarity can be performed by holding the tip of the endoscope approximatelythree inches above a nonglaring, printed white surface. Move the tip of theendoscope progressively closer to the printed surface until it is aboutone-quarter inch away. The image should be crisp and clear, with minimaldistortion. If the image is discolored or hazy, it may be due to impropercleaning, a disinfectant reside, a cracked or broken lens, the presence ofinternal moisture, or external damage.

Inspect the optical fibers surrounding the lens train at the tip of theendoscope by holding the light post toward a bright light. Black dots andshadowed areas may indicate broken, damaged, or dirty fibers, and will cause aloss of light to be transferred. Directing the tip of the scope toward a brightlight and observing the light post can provide the same information.

Delivery Systems

A variety of reusable and disposable sheaths and cannulae in numerousconfigurations are available for use with endoscopes. They provide access tobody cavities and organs and allow irrigation, distention, drainage, andintroduction of accessories. The following precautionary measures should beconsidered 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, andallow for introduction of accessories (with or without deflection), and theapplication of electrosurgical energy to resect or coagulate tissue. Examplesinclude a resectoscope working element, accessory ports or a reducer cap orsleeve used in laparoscopic procedures.

By design, the shafts of bridges and other rigid accessories are constructedof thin metal tubing due to size constraints. These can be dented or bent easilyand 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 andgrasping forceps, stone baskets, scissors, catheters or stents, and electrodes.Reusable accessories should be checked thoroughly for function and integritybefore and after each use. (Insulation must be intact on all electricalcomponents.) Manufacturers are not legally responsible if an item labeled"disposable" or "single-use only" is reused and thenmalfunctions. Adhere to all manufacturers' label instructions.

Cleaning, Disinfecting, and Sterilizing of Endoscopic Instruments

Laparoscopic hand instruments are the biggest challenge to OR personneltoday. These instruments are extremely difficult to clean because of the longshaft and jaw assembly, which may trap debris. The positive pressure of theinsufflated abdomen, blood and other body fluids flow into these channels andmay be difficult or impossible to remove. Many of these instruments cannot bedisassembled to facilitate manual cleaning, and ultrasonic cleaning systems maybe contraindicated due to the small joints and jaws.

These instruments should be wiped frequently to remove any visible soil, andshould be immersed in an enzymatic cleaning solution immediately following aprocedure to initiate the decontamination procedure. Channels should be flushedcopiously and jaws should be brushed vigorously.

The initial and most important step of reprocessing is thorough cleaning toremove gross soil, including microorganisms (bio-burden), which allows thedisinfectant or sterilizing agents to work effectively. Organic materials mayinactivate these agents or present a barrier that prevents disinfectants fromreaching all surfaces of an instrument. Manual cleaning is the safest method touse for rigid and single-lumen flexible endoscopes and accessories. Ultrasonicwashers can damage and loosen small joints and remove adhesives and lubricants.The mechanical washer/disinfectors designed for flexible GI scopes commonlygenerate pressures too high for the smaller lumens common to flexible endoscopesused in urology and gynecology.

The 1992 OSHA Bloodborne Pathogen Standard should be referred to whenmanually cleaning instruments. Proper personal protective equipment (PPE) shouldbe worn. This includes an impervious gown or apron, heavy-duty gloves, and eyeprotection to avoid splatters from lumen brushes. Both the external and internal(lumen) surfaces of endoscopic instruments must be cleaned. Refer to theendoscope 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 removeorganic soils effectively and actually may leave a residue on the instrumentsthat may inhibit the subsequent disinfection or sterilization process. Enzymaticdetergents are excellent choices for cleaning endoscopic instruments. Theenzymes used in these detergents are specific to protein, sugar, or fat. Choosean enzyme detergent that is effective for the materials and solutions to whichthe instrument is exposed. Refer to the manufacturer's label for useinstructions, including temperature of the water used to prepare the detergent.If an instrument is not cleaned properly, it cannot be sterilized ordisinfected.

Sterilization

Steam is the most common and least expensive method of sterilization.However, many lensed endoscopic instruments cannot be steam sterilized. Eveninstruments and telescopes marketed as "autoclavable" will last longerif processed by alternative methods.

Ethylene oxide gas has been the standard for sterilizing heat-sensitiveitems, including endoscopes. Sterilization cycles are typically one and one-halfto two hours at 55°C. Items must then be aerated mechanically for eight to 12hours. Ethylene oxide (EO) is being gradually replaced in some hospitals withother sterilization methods, such as steam, vapor-phase methods and paraceticacid because of cost and safety concerns. However, caution should exercisedbefore eliminating EO, since some of the alternatives have significantprocessing limitations and materials compatibility issues, including devicelumen size (that can be sterilized) or lack of storage life of the devices(just-in-time sterilization). The Steris System (Steris, Mentor, Ohio) usesperacetic acid in a proprietary liquid processor to sterilize items in less than30 minutes at 50-55°C. This method is a just-in-time process and sterilitycannot be maintained for long term storage.

Plasma and/or vapor phase are another sterilization modality for endoscopicinstruments. Sterrad (Advanced Sterilization Processes of Irvine, Calif.) isFDA-approved for use in the United States. Check with the company forrestrictions on lumen sizes which have been approved.

Disinfection

If sterilization is not possible, high-level disinfection is recommended forpatient-care items that come in contact with mucous membranes. High-leveldisinfectants are sporicidal, bactericidal, virucidal, and fungicidal agentsthat remove most bioburden, with the exception of some spores. The FDA regulatesthe label claims as they pertain to the use of the product to disinfect medicalinstrumentation, particularly the time required to kill specified organisms.

Commercial preparations of glutaraldehyde are available in both alkaline andacidic formulations. Although the slightly acidic preparations appear to be safefor endoscopic instrumentation, alkaline preparations are more common. Thesolutions are available in 2.4% or 3.5% concentrations. The 2.4% concentrationswithout surfactants are the recommended solutions for endoscopic instruments.Surfactants serve as wetting agents to reduce surface tension and allow thedisinfecting solution to penetrate areas that water is unable to reach. However,surfactants may leave a residue that is electrically conductive, difficult torinse off, and may prohibit small joints from moving freely.

Removing all traces of disinfectant by rinsing the instruments is extremelyimportant. Glutaraldehyde is very caustic to skin and mucous membranes and couldcontribute to chemical burns. Glutaraldehyde manufacturers are now recommendingthree separate, sterile rinses of at least one minute each. The rinse water isnot to be reused. Please refer to the glutaraldehyde package inserts forspecific instructions on use, reuse, rinsing, and disposal.

More information about glutaraldehyde is available from the manufacturers intheir product inserts. Pay careful attention to the labels on all products toreduce the possibility of damage to your instrumentation, and injuries to yourpatients and yourself. Be sure cleaning products are compatible with thedisinfectant or sterilizing agent. Avoid the use of highly alkaline or highlyacidic cleaners as they may damage the instruments.

Conclusion

Reusable endoscopic instruments can be reprocessed safely and effectively,providing they are cleaned and sterilized or disinfected according to themanufacturers' recommendations. All cleaning, disinfecting and sterilizingprocesses must be standardized and monitored to ensure process quality. Refer tothe instrument and chemical manufacturers' written instructions forcompatibility and usage. Establish specific policies and procedures to ensureproper handling and standardized practices.

Key points covering preventive care and maintenance of endoscopicinstruments:

  • Do not allow instruments to dry prior to cleaning. If it is not possible to clean immediately, immerse instruments in distilled water. An enzymatic detergent should be added in accordance with the manufacturer's written instructions for use.

  • Most endoscopic instruments must be manually cleaned. Do not use ultrasonic or other mechanical devices unless this modality is specifically cited as appropriate in the instructions for use or operating and maintenance manual. These processes can damage adhesives, remove lubricants, and scratch or dent surfaces.

  • Only informed personnel should handle endoscopic instruments.

  • Do not stack instruments during cleaning, disinfection, sterilization, or storage.

  • Do not bend or drop instruments.

  • Avoid abrasives.

  • Loosely coil all cables including those attached to cameras and power sources.

  • Reduce intensity of light sources to low and allow them to cool before turning off the power. This will prolong the life of the bulbs.

  • Some flexible endoscopes have venting mechanisms for sterilization and/or disinfection purposes. Closely follow the manufacturer's written guidelines to prevent expensive and frequent repairs.

  • Do not reuse or reprocess any devices labeled "single-use."

Eileen Young, RN, is a gynecology clinical specialist at CirconCorporation in Stamford, Conn.

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