How to… clean an endoscope without being scared of breaking it!
In our last post, we began our introduction to endoscopy series. We looked at the different types of endoscope used in practice, how they work, and how to prepare, handle and care for them. As veterinary nurses, endoscopy assistance features heavily in our role and, after their use, cleaning and reprocessing endoscopes often falls to us! This can be daunting for the nurse in practice; due to their fragility and cost, the fear of damaging the scope can be very real! Today we’ll walk through how to clean and reprocess an endoscope without that fear. Ready to jump in? Let’s go!
The method of endoscope cleaning used will vary depending on the type of endoscope you are using (flexible or rigid), and the equipment you have available to you in practice. We’ll chat through 3 common ways of endoscope cleaning today, but first, there are a few things you can do at the end of your endoscopic procedure that will make your life a whole lot easier when it comes to cleaning.
Immediately after use
As soon as you’ve finished your procedure, before the endoscope is disconnected from the tower, the following steps should be completed:
If you are using a flexible endoscope:
Flush the air and water channel through with distilled water by pressing down the blue air/water button fully.
Place the end of the insertion tube into a jug of enzymatic cleaning solution (pre-prepared to the manufacturer’s instructions) and suction this through the endoscope, by depressing the red suction button fully.
Take a swab dipped in the cleaning solution, or a commercial endoscope disinfecting wipe, and wipe the whole insertion channel and body of the endoscope.
Hang the endoscope back up on the scope tower.
If you’ve used a rigid endoscope:
Fill a 20ml syringe with pre-prepared enzymatic cleaning solution and flush through all ports on the working sheath.
Very carefully remove the endoscope from the working sheath, gently wipe over the scope with a swab dipped in cleaning solution, and immediately place the endoscope in its plastic protective sleeve.
Place the endoscope in a safe location where it cannot get knocked or dropped (personally, I like to store rigid endoscopes in sterilisable plastic equipment boxes, alongside any accessories that accompany that particular scope).
These initial steps help prevent any material present within the endoscope channels from hardening, which can quickly result in a channel blockage. By flushing the endoscope through with cleaning solution, and wiping the outside over, any gross contamination is removed. This means that you can take time to fully recover your patient (and maybe even get a lunch break in if necessary!) without having to perform a full endoscope clean immediately.
The full clean
After those initial steps have been performed, you’ll need to go back to your endoscope and perform a full clean.
Cleaning a rigid endoscope
Rigid endoscopes are generally easier to clean than flexible scopes, though are very delicate and so should be handled with extreme care, especially when cleaning the rigid scope itself (when it is not protected by a sheath or plastic sleeve). To clean your rigid endoscope, simply follow these steps:
Prepare 3 baths as follows:
1 tray of enzymatic cleaning solution, diluted according to the manufacturer’s instructions. NB. Some solutions specify that you will need water of a certain temperature; if this is the case, check your water temperature with a standard thermometer to ensure it is not too hot or cold.
1 tray of instrument disinfectant solution, again prepared according to the manufacturer’s instructions.
1 rinsing tray containing distilled water.
Place your rigid scope (protected within its plastic sleeve), along with any working sheaths, biopsy or grasping forceps used, into the cleaning bath.
Using a swab wet with cleaning solution, gently wipe over all areas of the endoscope.
Return the scope to its plastic protective sleeve, and leave to soak in the solution for the required contact time.
Open all taps on the working sheath ports. Using a rigid endoscope cleaning brush, brush through each port several times, cleaning the brush in the cleaning solution each time.
Flush through each port on the working sheath using a large syringe filled with cleaning solution. Repeat this several times.
Wipe over the outside of the working sheath with cleaning solution and swabs, and then soak the sheath for the required contact time.
Gently brush the jaws and cups of any forceps used.
Wipe over the outside of the forceps, and then soak them for the required contact time.
Repeat the above steps in the instrument disinfectant bath.
After the cleaning and disinfection steps are complete, place the endoscope, sheath and forceps in the distilled water bath.
Flush through the sheath ports with distilled water, before drying all items thoroughly.
Return the items to their instrument box and package them for EO sterilisation or autoclaving as appropriate (not all rigid scopes can be autoclaved, so you should check with your endoscope manufacturer if this is safe to do).
Cleaning a flexible endoscope
There are actually two methods of cleaning your flexible endoscopes - automatic and manual cleaning. In most cases, manual cleaning is what you’ll be performing in practice, though a few of you may be lucky enough to have an automatic endoscope cleaner. I’ve used both - I’m currently a manual cleaner but my last practice had an automatic unit and it was amazing!
Manual cleaning method
Fill 3 trays as previously described - a cleaning bath, disinfection bath and distilled water rinsing bath. To completely cover your largest flexible endoscope (GI scope), you’ll usually need around 7-10L of solution.
Leak test your endoscope. Pump the pressure tester up to around 160mmHg and watch for 3-5 minutes to ensure the pressure level does not drop. An initial drop of 1-2mmHg may be normal, but the pressure should remain steady after that. If there are any concerns that a leak may be present, do not clean the endoscope. We’ll talk about what to do with a leaky scope later!
If your leak test passes, leave the endoscope pressurised but remove the pressure tester from the pressure compensation valve. We do not want to leave that channel open, as it means water can enter the scope - so make sure to remove the tester before the scope is submerged!
Submerge your endoscope in the cleaning solution. Most endoscopes now are safe to be completely submerged in water, but please do double-check with your manufacturer to ensure this is safe for your particular endoscope.
Remove any channel caps or accessories and place these in the bath alongside the endoscope.
Using an appropriately-sized channel cleaning brush, brush through the instrument and suction channels multiple times. When doing this, ensure that the brush is run through the whole channel, cleaned in the cleaning solution, and fully removed before re-inserting it. Avoid brushing back-and-forth within the scope channels, as this can cause damage.
If your scope has an umbilical tube, the suction channel in this will also need to be brushed through. This can be performed by inserting the brush through the suction tubing attachment on the light guide plug, and brushing through until you see the brush exit through the body of the scope. It will actually come out of the site where the suction button normally attaches!
Attach flushing adaptors to the suction button attachment and the instrument channel access port. These adaptors are supplied alongside your endoscope at time of purchase, and are essentially a piece of tubing with a syringe port at one end, and a port which attaches to your suction channel/instrument channel at the other.
Fill a 50ml syringe with cleaning solution and flush through the channels multiple times.
Wipe over the outside of the endoscope, and any accessories, with a damp swab and cleaning solution.
Soak the endoscope and accessories for the appropriate contact time.
Move the endoscope and accessories to the disinfectant bath, and repeat steps 8-11.
After disinfection, move the endoscope to the distilled water rinsing bath and repeat the flushing process.
Remove the endoscope and all accessories from the rinsing bath and dry thoroughly.
Hang the endoscope up to continue drying, with any channel buttons/caps removed. This allows any residual water within the endoscope channels to drip out. If the channel buttons are in place, this can have a similar effect to placing your finger over a capillary tube - leaving the water in place inside the channels!
Thoroughly dry the pressure compensation valve, attach your leak tester and de-pressurise your scope.
Automatic cleaning method
The automatic endoscope cleaner essentially replaces the flushing step of the manual method. It is a cleaner unit, to which different flushing tubes attach. These flushing tubes are connected to various channels of the endoscope, and continually flush cleaning/disinfectant/rinsing solution through the endoscope, for a set time. They normally come with 2-3 baths which are filled with cleaning solution, disinfectant solution and distilled water, and the veterinary nurse still needs to perform the leak testing and channel brushing procedures as previously described.
What to do with a leaky scope
If you suspect that your flexible endoscope has a leak, the safest thing to do is not to use or clean it. A leak means that the outer protective covering of your scope is compromised, and fluids may enter the inner workings of the scope, causing corrosion and damage. This damage can be irreversible. Leaks can occur through damage during use or if an endoscope is improperly stored or handled, so careful handling and use will help minimise the risk.
If you’re leak testing a scope after use and find it is leaking, call your manufacturer’s repairs department and ask their advice. Often you’ll be sent a protocol for submitting a non-disinfected endoscope back to them for repair. This generally involves wrapping the endoscope in a waterproof, protective material, clearly labelling the endoscope as non-disinfected, and filling out some returns paperwork.
So that’s a how-to of all things endoscope cleaning! I really hope that this has helped dispel some of the myths that all endoscopes get broken during cleaning. As long as they’re handled gently and leak tested thoroughly before use, there is very little reason to be worried about endoscope handling. And don’t forget that endoscopes are put through their paces much more when they are being used, than they are when being cleaned!
References and further reading:
Cox, S. 2016. Endoscopy for the Veterinary Technician. Iowa: Wiley-Blackwell.
Merrill, L. 2012. Small Animal Internal Medicine for Veterinary Technicians and Nurses. Iowa: Wiley-Blackwell.
Disclaimer: Individual endoscope use and maintenance protocols may vary depending on your practice, the endoscopes you use, and the cleaning/disinfectant products used. The above protocols are intended as a guide only and are personally the protocols that the author uses in practice with good results. Veterinary Internal Medicine Nursing is not responsible for any issues which may arise as a result of their use. Any photos displayed or products mentioned are for reference only and are not product endorsements or recommendations.
