Gastroscopy

• 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:
  • Vomiting Vomiting.
  • Hematemesis.
  • Gastric neoplasia Stomach: neoplasia.
  • Chronic gastritis Stomach: chronic gastritis .
  • Gastric ulceration Gastric ulceration.
  • Pyloric outflow disorders Stomach: gastric outflow disease.

Advantages

• 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

Disadvantages

• 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.

• Radiography Radiography: abdomen , fluoroscopy and contrast studies (barium series).
• Exploratory laparotomy Laparotomy: midline.
• Barium-impregnated polyurethane spheres (BIPS) radiographic study.

Preparation

• Induction of anesthesia and/or sedation → 10-30 min.

Procedure

• Depends on the experience of the endoscopist → approximately 15-30 min.

Risk assessment

• Low risk.
• See complications.

Nursing expertise

• 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.

Minimum 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.

Ideal equipment

• 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.

Minimum consumables

• Clean water.
• Endoscope disinfectants.
• Formal saline, card and containers for preservation of biopsy samples.

Other requirements

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.

General Care

• Routine post-anesthetic observation.
• Check mucous membrane color, heart and respiratory rates in case of hemorrhage.
• Check there is no evidence of gastric dilation.

Special precautions

• Do not overinflate stomach.
• Apply only enough air to allow adequate visualization.
• Always deflate the stomach after gastroscopy to reduce risk of gastric dilation.

Potential complications

• Arterial bleeding from biopsy sites (rare).
• Gastric perforation from applying too much force.
• Iatrogenic damage to mucosa caused by advancing endoscope along gastric wall.

Refereed papers

• Recent references from PubMed and VetMedResource.

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.