Care of Endoscopic Instrumentation
By Eileen Young, RN
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.
Figure 1: A Rigid Scope
This article is not intended to be a substitute for the instructions for use in the operating and maintenance manuals. Nevertheless, it provides 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 (Figure 1). 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 reside, 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.
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 or a reducer cap 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 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 (bio-burden), 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 1992 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 remove organic soils effectively and actually may 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.
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 United States. Check with the company for restrictions on lumen sizes which have been approved.
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.
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.
Key points covering preventive care and maintenance of endoscopic instruments:
- 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 Circon Corporation in Stamford, Conn.