Contributors: Ken Harkin, James Simpson
Species: Canine | Classification: Techniques
- Examination of the gastric mucosal surface.
- Collection of gastric mucosal biopsy samples.
- Detection and retrieval of gastric foreign bodies Stomach: foreign body Gastroscopy: removal of a gastric stone FB.
- Percutaneous gastrostomy tube (PEG) placement Gastrostomy: percutaneous tube 1 (endoscopic).
- Investigation of:
- Non-invasive technique requiring no surgical intervention.
- Well-tolerated by sick dogs which would be unsuitable for laparotomy.
- Requires only light general anesthesia - rapid recovery.
- Good visualization of the gastric mucosa.
- Follow-up examination well-tolerated and useful for assessing response to treatment
- Does not detect motility disorders.
- Does not detect pyloric stenosis Stomach: pyloric stenosis.
- Will not detect pathology lying under the mucosa.
- Limited to stomach and descending duodenum.
- Difficulty passing through pylorus in some cats and small dogs.
- Cannot carry out surgical correction compared with laparotomy.
- Expensive equipment.
- Technical difficulty in procedures.
- Induction of anesthesia and/or sedation → 10-30 min.
- Depends on the experience of the endoscopist → approximately 15-30 min.
- Low risk.
- See complications.
- Good level of competence required for assisting in procedures, monitoring anesthetic and assisting in biopsy collection and handling.
- High competence for care and cleaning of endoscopic equipment.
- Fully-immersible fiber-optic flexible endoscope.
- Insertion tube diameter 7-9 mm.
- One meter insertion tube length.
- ONLY use an end-viewing endoscope.
- Four-way tip deflection.
- MUST have cold light source with air pump and water wash facility.
- Fenestrated biopsy forceps for collection of mucosal biopsy samples.
- Cleaning brushes for biopsy channels.
- Water leakage tester.
- Video endoscope:
- Excellent magnified image presented on screen.
- Detection of lesions much easier.
- Allows for multiple person viewing.
- Excellent for video recording procedures and/or collecting still images.
- Excellent as a training aid.
- Xenon light source.
- Insertion tube diameter 7-9 mm.
- Suction unit for aspiration of unwanted gastrointestinal secretions.
- Cytology brushes, grasping forceps and balloon catheters.
- More than one endoscope for examination of different parts of the gastrointestinal tract.
- Endoscope cleaning trolly.
- Ultrasonic cleaner for biopsy forceps.
- Clean water.
- Endoscope disinfectants.
- Formal saline, card and containers for preservation of biopsy samples.
Care and maintenance
- Storage of endoscopes:
- ALWAYS store endoscopes in a safe location where accidental knocks can be avoided.
- ALWAYS store endoscopes with insertion tube hanging vertically.
- Do NOT store endoscopes in their carrying case.
- See supplier for further details of endoscope 'hangers'.
- Cleaning and disinfection:
- Follow the manufacturers recommendations at all times.
- Use an endoscope cleaning bath wherever possible.
- Use whatever disinfectant the manufacturer recommends.
- Gigasept, Cidex and Dettol endoscopic disinfectants are available.
- Follow health and safety rules regarding use of these products.
- Suitable premedication.
- Nil per os for a minimum of 12 hours, longer if there is delayed gastric emptying.
- Light general anesthesia.
Step 1 - Patient preparation
- Following induction of anesthesia - it is essential to intubate patient.
- Tie endotracheal tube to mandible to aid passage of endoscope.
- Lay patient in left lateral recumbancy.
- Place mouth gag to protect endoscope.
- Pass endoscope.
- Insert endoscope along hard palate and into proximal esophagus .
- Advance scope along length of esophagus (see Esophagoscopy Esophagoscopy ).
Step 2 - Enter stomach
- Once cardia is reached gently apply force on endoscope to enter stomach.
- 'Red out' will occur during intubation of stomach (vision is lost).
- Once you feel the endoscope pass the cardia, STOP, gently inflate stomach with air.
Step 1 - Examine rugae
- Only introduce enough air to visualize the mucosa.
- It is very important NOT to overdistend the stomach with air.
- Examine the rugal folds of the fundus.
Step 2 - Examine antral region
- Advance endoscope in the direction of the rugal folds. This will direct you towards the antrum Gastroscopy: gastric navigation and intubation of the duodenum.
- The angular incisure of the lesser curvature of the stomach will be seen as a band of mucosa and marks the entrance to the antrum.
This is an important endoscopic landmark.Rugal folds are NOT seen if stomach is overinflated with air.
- Retroflex the endoscope to visualize the cardia Gastroscopy; gastric J-maneuvre.
Step 3 - Examine pylorus
- Pass endoscope along antrum to visualize the pylorus .
- Bile may be observed entering the stomach as may antral peristaltic contraction.
These contractions are not seen if the stomach is overinflated.
Step 4 - Biopsy
- Collect biopsy samples from any focal lesions observed.
- In any case collect biopsy samples from the fundus, body, cardia and antrum.
- A minimum of 6 biopsy samples are required.
Evacuate air completely with endoscopic suction upon completion.
- Do not overinflate the bowel as this will make mucosa stretch tightly reducing ability to collect samples.
- Try and advance biopsy forceps perpendicular to the mucosa.
- Tent mucosa with suction before closing biopsy forceps and retrieving sample.
- Deeper samples can be collected by sampling repeatedly at the same site.
- Perforation will occur if this is done too frequently.
- Capillary bleeding from biopsy sites is normal.
Step 1 - Remove endoscope
- Straighten insertion tube.
- Gently withdraw endoscope.
- Support end of scope as it is withdrawn to prevent damage.
- Routine post-anesthetic observation.
- Check mucous membrane color, heart and respiratory rates in case of hemorrhage.
- Check there is no evidence of gastric dilation.
- Do not overinflate stomach.
- Apply only enough air to allow adequate visualization.
- Always deflate the stomach after gastroscopy to reduce risk of gastric dilation.
- Arterial bleeding from biopsy sites (rare).
- Gastric perforation from applying too much force.
- Iatrogenic damage to mucosa caused by advancing endoscope along gastric wall.
Other sources of information
- Simpson J W (1996) Gastrointestinal Endoscopy. In: Manual of Canine and Feline Gastroenterology. D Thomas, J W Simpson & E J Hall (eds), BSAVA, Cheltenham. p 20.
- Tams T R (1990) Small Animal Endoscopy. C V Mosby, St Louis.
- Key-Med UK Ltd, Keymed House, Stock Road, Southend-on-Sea, Essex SS2 5QH, UK.
- Arnolds Veterinary Products, Cartmel Drive, Harlescott Shrewsbury SY1 3TB, UK.
- Veterinary Endoscope Services, Alder House, High Road, Rayleigh, Essex SS6 7SA, UK.