5 things you need to know about gastrointestinal endoscopy
Continuing our endoscopy series, today we’re looking at the most common type of endoscopic procedures we perform in practice… gastrointestinal endoscopy! We’ll break down the 5 areas you need to know about as a veterinary nurse - what it actually is, why it’s performed, how it’s performed, how to prepare and nurse your patients, and how to collect and handle samples.
If you haven’t already, be sure to check out the other posts in the endoscopy series. Ready to jump in? Let’s do it.
What is gastrointestinal endoscopy?
A GI scope is the endoscopic examination of different areas of the gastrointestinal system. This is performed using a flexible endoscope called a gastroscope. Broadly speaking, we can break down GI endoscopy into three procedures, depending on the areas of the GI tract we want to examine.
Upper GI Tract Endoscopy is the examination of the oesophagus, stomach and duodenum (+/- the proximal jejunum in smaller patients)
Lower GI Tract Endoscopy (or colonoscopy) is the examination of the descending colon, transverse colon, ascending colon and ileum (the final third of the small intestine).
An Upper and Lower GI tract Endoscopy is the examination of all the above structures.
Why is it performed?
GI endoscopy is an important diagnostic tool in the investigation of many gastrointestinal diseases. It allows us to examine the gastrointestinal tract in a minimally invasive way, facilitates visualisation of the intestinal mucosa, allows identification of ulcers, inflammatory changes, masses or other abnormalities, guides collection of biopsy samples and guides foreign body removal.
Diseases such as inflammatory bowel disease (IBD) require the collection of biopsies for histopathology to confirm the disease, as the presence of inflammatory cells within the GI tissue is required for a diagnosis.
It is, therefore, an important procedure for the veterinary nurse to be aware of, since we play a huge role in supporting these patients before, during and after the procedure.
How is it performed?
An upper GI endoscopy begins with the insertion of the endoscope into the mouth, and the examination of the oesophagus. Air is pumped through the endoscope into the GI tract as necessary, to inflate the structures, allowing passage of the endoscope and visualisation of the GI mucosa. After the oesophagus has been briefly examined, the lower oesophageal sphincter is intubated and the endoscope enters the stomach at the level of the cardia. The endoscopist inflates the stomach enough to facilitate visualization of the pylorus and intubates this to enter the duodenum. Once the duodenum has been entered, the clinician thoroughly examines the duodenum and begins to collect biopsies. After multiple biopsies have been collected, they return to the stomach and inflate it, to allow visualisation of the gastric mucosa (otherwise areas would be hidden under the rugal folds). Each area of the stomach (cardia, fundus, body, angularis and antrum) should be fully examined. Multiple biopsies are collected from various areas of the stomach (ideally from each area). The endoscope is then withdrawn back into the oesophagus and this is examined fully as the endoscope is withdrawn from the patient. The oesophagus is generally not biopsied as it is challenging and risks significant complications.
A lower GI endoscopy begins with the insertion of the endoscope through the anus into the rectum. Working from distal to proximal, the descending colon, transverse colon and then ascending colon are inflated and examined as the endoscope is advanced, until the endoscopist reaches the ileocaecocolic junction (ICCJ). The entrance into the ileum is a ‘button’ of tissue which can be intubated with the endoscope to enter the final portion of the small intestine. Next to this ‘button’ is a large hole, which is the entrance to the caecum (a blind-ended sac which is not examined during endoscopy). When inside the ileum, the intestine is again inflated, visualised and biopsies are collected. Working backwards, the endoscope is then withdrawn back into the colon, the colonic mucosa is fully examined and multiple biopsies are collected from this area.
An upper and lower GI endoscopy combines both of the above procedures; starting with the upper GI endoscopy before the patient is turned and prepared for the lower GI endoscopy.
How is the patient prepared?
A large part of the veterinary nurse’s role is the preparation, monitoring and care of patients undergoing endoscopy.
Patients should be fasted for an appropriate amount of time. The duration for which food should be withheld varies depending on the exact procedure to be performed. As a general rule, patients undergoing only upper GI endoscopy should be fasted for around 12-24 hours (depending on whether any delayed gastric emptying is present) to ensure the stomach is empty.
Patients undergoing lower GI endoscopy require a longer fasting period, to ensure the entire GI tract is free of food/faecal matter. These patients should be fasted for 24-48 hours, depending on the individual patient and clinician’s preference.
Patients undergoing lower GI endoscopy also require preparation of their colon to ensure it is clean, and that the clinician can see the mucosa. This may be achieved via multiple warm water enemas, via the administration of bowel cleansing solutions, or via a combination of both.
If a patient has had barium as part of their diagnostic work-up prior to endoscopy, the endoscopy should be delayed until the barium has worked its way out of the patient’s system. This is important because barium causes severe damage to the endoscope - so if you are planning procedures for a patient needing both endoscopy and a barium study, it’s better to scope first and perform the barium study afterwards.
After the patient has been appropriately prepared, they should receive a pre-anaesthetic examination and an anaesthesia plan should be developed. Particular events to consider when anaesthetising GI endoscopy patients include hypercapnia (as the inflated stomach may cause hypoventilation) and reflux/regurgitation on recovery (due to intubating the lower oesophageal sphincter during the procedure).
Following anaesthetic induction, the patient should be placed in left lateral recumbency as this makes it easier for the clinician to intubate the pylorus. If performing an upper GI endoscopy, the patient’s head should be away from the anaesthetic machine (ensure you have sufficient monitoring/patient access, and long circuit tubing before anaesthetising the patient!).
A mouth gag should be placed for all patients undergoing upper GI endoscopy, to prevent bite damage to the endoscope.
Patients undergoing lower GI endoscopy should be positioned with their head towards the anaesthetic machine, again in left lateral recumbency. A warm-water enema should be performed prior to endoscopy. To minimise mess and keep the patient clean, wrapping their tail with vetwrap (or similar) is a good idea, and fluid collection drapes can be placed over the end of the table to collect fluid and other mess.
During anaesthesia, particularly close attention should be paid to the patient’s respiration, capnograph trace and ETCO2 reading, to detect hypoventilation associated with gastric inflation.
On recovery, patients should be kept warm and thorough monitoring should continue until they regain consciousness. Monitoring for reflux is particularly important in the recovery period, and if possible, their oesophagus should be suctioned free of any fluid by the endoscopist prior to recovery.
How to handle instruments and collect samples
Another big part of endoscopy nursing is the collection of diagnostic samples. The veterinary nurse is responsible for correctly operating biopsy forceps and other channel instruments, as well as collecting, handling and submitting samples for analysis. Here are my tips to maximise patient safety, prevent endoscope damage and collect good quality samples when operating channel instruments:
Advance any forceps gradually (2cm at a time) and stop if you feel increased resistance when trying to advance them. Communicate with your clinician, as they may need to un-bend the end of the insertion tube before the forceps will advance.
Ensure that you keep all channel instruments in the ‘closed’ position until you can see the end fully exit the instrument channel. Opening the forceps inside the channel can cause damage to the endoscope.
After exiting the instrument channel, open your forceps and advance them as directed by the clinician, whilst held in the ‘open’ position.
When directed, purposely but carefully push the forceps against the area to be biopsied, and firmly close the forceps.
Holding the forceps in the closed position, withdraw them fully from the instrument channel.
When removing samples from the forceps, this can be done either by carefully ‘hooking’ them out of the forceps using a 25g needle, or by ‘shaking’ the end of the forceps in a sterile pot of saline, to free the biopsies from the forceps.
Transfer the biopsies into a endoscopic biopsy cassette, using one cassette per anatomical region.
Gently close each cassette and place each in a labelled formalin pot for submission to the laboratory.
So that’s a ‘how-to’ of all things GI endoscopy! I hope that’s been useful. Don’t forget that you can download a full booklet of endoscopy equipment lists to complement this blog series - simply enter your email address below, and the link to our resource library will be sent straight to your inbox, alongside the password to access it!
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.
