Endoscopy equipment is expensive to purchase, however if maintained correctly it will be an invaluable investment in diagnostic investigation for patients. It is imperative that there is a good understanding of how to clean endoscopes. Poor cleaning and maintenance can pose significant health and safety implications, in the worst case scenario causing transmission of disease to patients.
Maintenance of endoscopes includes safe handling, bedside procedure, disinfectant and sterilization, storage and repairs/servicing.
Safe handling
Endoscopes are made up from very delicate components including fibre optics which are arranged in high precision, well ordered coherent optical fibre bundles, charged coupled device chips and small channels (Figure 1) (Holland and Shoop, 2000). These parts can become damaged if care is not taken when handling, setting up the endoscope, during the procedure, cleaning and transportation.
If endoscopes are being transported away from the endoscopy unit, the endoscope should be stored in its original case to prevent damage (Simpson and Argyle, 1999).
When handling the endoscope it should always be held with both hands to prevent dropping it or banging any parts of it. When hanging the endoscope before the procedure, ensure that it is not in an area where it may be knocked off its stand or bashed against any surfaces.
The tip of video endoscopes contain a small chip that transfers images to the TV monitor — care should be taken not to bang the insertion tube on any surfaces. Forceful bending or over exhaustion of the endoscope can cause damage to the fibre optic fibres (Holland and Shoop, 2000).
Before starting the procedure a mouth gag should be placed in anaesthetized patients to prevent any damage to the insertion tube.
Ionized/distilled water
Prolonged use of untreated tap water can cause limescale to build up in the endoscopy channel. To prevent this damage ionized or distilled water should be used for flushing the channels (Nelson and Muscarella, 2006).
Endoscopy reprocessing
Cleaning of endoscopes is a three stage process that includes pre processing (see Step-by-step guide), processing and post processing. The full three steps should be performed after every patient, and at the beginning of the daily list the endoscopes should be disinfected and dried (Nelson and Muscarella, 2006).
High level disinfection
Flexible endoscopes are not compatible with autoclaves, so a careful decision needs to be taken to find the most appropriate high level disinfectant to successfully decontaminate the endoscopes and accessories. There are many types of disinfectants on the market providing adequate cleaning of endoscopes.
The ideal properties of disinfectants include:
Types of disinfectants available
Glutaraldehyde was formerly widely used but has since been taken off the UK market because of advances made to other disinfectants and the health and safety concerns to personnel handling the disinfectant. It also caused residual protein material to stick to the channels in the endoscope.
Ortho-phthalaldehyde is more stable than glutaraldehyde, it is odourless and does not emit the noxious fumes that glutaradehyde emits. It kills most bacteria and viruses and has a mycobactericidal activity better than glutaraldehyde. As with other aldehydes, protein material can stick to the channels if inadequate pre processing is performed, causing health and safety concerns to the patient (Walsh et al, 1999).
Peracetic acid is available in numerous disinfectants on the market. It is effective against a wide range of micro-organisms, however the contact time varies depending on the preparation used (Wilkinson et al, 1998).
Alcohol is similarly as effective as glutaraldehyde against bacteria, micro bacteria, viruses and resistant pseudomonas. Activities against enterovirses are slower though, and alcohol does not have any activity against bacterial spores. Over time alcohol damages plastic, seals and the adhesive used on endoscopes (Wilkinson et al, 1998).
Chlorine dioxide is a broad spectrum agent with rapid activity against bacteria, viruses and spores (Wilkinson et al, 1998).
Superoxidized water is a mixture of active elements derived from salts by electrolysis through a proprietary electrochemical cell. The affectivity of this disinfectant is reduced in the presence of organic matter. This preparation usually comes as a single use product (Wilkinson et al, 1998).
Ethylene oxide is a sterilization process that uses low temperature steam, formaldehyde and hydrogen peroxide gas plasma. Ethylene oxide is classified as a human carcinogen. This process is impractical as the cycle is long and equipment cannot be used for a period of time (Wilkinson et al, 1998).
Test strips are available for most disinfectants to test the effectivity of the disinfectant. This should be performed daily and a record kept showing this is being checked.
Reprocessing methods
Automatic reprocessors are valuable if performing large amounts of endoscopy on a daily basis (Figure 2). If the practice/hospital case load is small other options available are cleaning trolleys, which allow the endoscope to have the cleaning solutions manually pumped through the channels (Figure 3). Cat litter trays and a syringe can be used but are not ideal as the amount of fluid that will be pushed through the channels will vary.
The process for disinfection of endoscopes includes rinsing, detergent cycle, rinse, disinfectant cycle, rinse cycle and then drying (Figure 4). Contact times will vary depending on the disinfectant used and manufacturer's guidelines should always be followed.
Disinfectants can pose a health and safety concern for staff handling these chemicals. Prolonged exposure can cause asthma and other respiratory disease, and contact with the skin can cause reactions such as chemical burns (Vyas et al, 2000). When handling disinfectants appropriate personal protective equipment (PPE) should be worn. This includes gloves, aprons, goggles and masks/respirators. The process of disinfection of endoscopes should be performed in a well ventilated room.
Drying and storage (post processing)
Once disinfection is complete the endoscope should be hung to dry. Air should be blown through the channels to remove residual fluid and air aspirated through the suction channel.
Endoscopes should be dry before putting away for storage; wet channels can cause transmission of pseudo outbreaks of waterborne micro-organisms to the patients (Nelson and Muscarella, 2006).
Once dry, endoscopes should be stored in a lockable cupboard with ventilation. There should be space for the insertion tube to hang vertically (Figure 5), preventing damage to the channels. The angulation locks should be released to minimize strain on the insertion tube (Leung, 2002).
Preventative care and maintenance
Having a service contract or insurance on your endoscopy equipment is invaluable to help cover high costs of repair and servicing.
Endoscopes should be regularly inspected; if any faults or suspected faults are detected then the endoscope should be sent for repair. Inspection of the bending mechanism can be achieved by operating the angulation controls slowly to the limit in each direction and checking for smooth operation. When the endoscope is new or when it comes back from a service the degree of angulation can be recorded and checked against regularly.
Any repair should be carried out by a professional/qualified person and attempts of do-it-yourself repairs will usually result in further damage and possible health and safety implications to the patient or staff.
Blockages can occur in the channels of the endoscopes; this is usually in the air channel. These blockages should be removed as soon as possible as once they are dried on or fixed with disinfectant they will most likely need to be removed by a specialist. A special valve to remove blockages will be available from the manufacturer of the endoscope.
Over time the fibre optics can become damaged and broken, this will manifest with small black dots either on the television monitor or while using the eyepiece. This is not usually a problem unless lots of fibres become damaged and the view becomes obscured. Careful handling and storage can prolong the life of the fibres.
Endoscopy pistons should be frequently inspected for any damage and loss of ‘o’ rings. Regular maintenance of pistons includes lubrication with specific endoscopy silicone oil; this should be done after cleaning of the pistons. There are small ‘o’ rings on the pistons that over time can become worn or lost — these should be replaced or a new piston purchased. Worn pistons will result in inadequate use of air/water and suction.
Conclusion
There is a lot to be considered when using endoscopy as a procedure in veterinary medicine. However, if the endoscope is maintained correctly it will become an invaluable diagnostic tool.
If inappropriate maintenance or inadequate cleaning is performed this could pose a significant risk for patients.
High levels of care and maintenance of the endoscopes will prolong the life and reduce costs in external repairs and servicing.
Cleaning, disinfection and sterilization is a crucial process in the prevention of disease transmission and nosocomial infections to the patient. This comes down to training and adherence to protocols set by the hospital/practice and the manufactures of the equipment.
There are many different types of disinfectant protocols in place for endoscopes, and there is no one brand that is suitable. It is best to find a protocol that works for the practice and the type of method being used for reprocessing the endoscopes. Health and safety considerations for staff handling the chemicals should be considered and appropriate PPE provided.
If all the points highlighted are adopted into routine care of endoscopes then the life of the endoscope and its equipment may be prolonged.