Contributors: Ken Harkin, James Simpson

 Species: Canine   |   Classification: Techniques

Introduction Requirements Preparation Procedure Aftercare Outcomes Further Reading




  • 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 Problems

  • Technical difficulty in procedures.

Alternative Techniques

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

Time Required


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


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

Decision Taking

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.

Materials Required

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.

Dietary Preparation

  • 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 Endoscopy introduction of esophagoscope into 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.

Core Procedure

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 Endoscopy: pylorus normal.
  • 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.


Further Reading


Refereed papers

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.