Oesophago-gastro-duodenoscopy (OGD)

Why is OGD performed | Pre-operative Preparations | Procedures | Post-operative Instructions | Possible Risks and Complications

Oesophago-gastro-duodenoscopy (OGD) is an examination of the inside of the upper digestive tract by using a flexible video-endoscope which is passed through the mouth into the oesophagus, stomach and duodenum. It allows your doctor to have direct vision of the upper digestive tract and to detect pathological change, for example, tumor, ulceration or polyps etc. Your doctor will take biopsy for pathological examination and may perform polypectomy and therapeutic haemostasis when necessary.

Why is OGD performed?

  • Anemia or gastrointestinal bleeding
  • Stomach ache
  • Gastroesophageal reflux
  • Difficulty in swallowing
  • Unexplained abdominal pain
  • Polyps / tumors
  • Gastric cancer screening
  • Removal of swallowed objects, e.g. Fishbone

Pre-operative Preparations

  • The reason for conducting an OGD, the procedure and the possible complications will be explained by the doctor and a consent form must be signed prior to the procedure.
  • Please inform the doctor if the patient is or might be pregnant.
  • Please inform the doctor if the patient currently takes any drugs or medications particularly for diabetes or that could affect blood clotting, for example:
    - Aspirin products
    - Arthritis drugs
    - Antiplatelet drugs, e.g. Plavix, Persantin, Pletaal, Pradaxa
    - Blood thinners, e.g. Warfarin (anticoagulants)
    - Insulin
    - Diabetic tablets
    - Iron supplements
    - Any Chinese medicines or herbal remedies
    - OGD can be conducted as an out-patient or in-patient. Please consult your doctor for the arrangement.
  • No food or drink six hours before OGD.
  • Please change into a surgical gown after removing all clothing including undergarments, dentures, jewellery and contact lenses.


  • Patient has to lie on his left side and wear a small plastic mouth guard.
  • Local anaesthetic spray to the throat and intra-venous sedative will be administered according to doctor’s prescription.
  • Doctor will pass the gastroscope into patient’s stomach through the mouth. It is normal if the patient feels bloating and abdominal distention during the procedure.
  • The procedure will usually take 15 minutes.
  • The procedure can be conducted without any sedation. Please consult your doctor for information.

Post-operative Instructions

  • After the OGD, patient should stay in bed until the sedative effect of drug has been completely worn off. It usually takes 3 – 4 hours.
    For Out-patient
    For your safety, please arrange a responsible adult to stay with you when you leave the hospital. If there is no companion, recovery bed has to be arranged for you after the procedure (additional charge for observation will be levied).
  • Patient can only resume oral intake 1 hour after the OGD (For in-patient, please confirm with ward nurse of the time for resuming diet).
  • As doctor will pump air into the stomach to enhance visualization, patient may feel mild gastric distension, stomach ach. Mild throat discomfort is also common.
  • If there is severe abdominal pain, medical personnel must be consulted immediately.

Possible Risks and Complications

  • Respiratory complication: e.g. Aspiration pneumonia
  • Haemorrhage (less than 1:1000), perforation (3 in 10,000) and death (1:10,000). If therapeutic procedures are required (e.g. polypectomy, endoscopic haemostasis etc), the risks are in general slightly higher
  • Soreness of throat
  • Bloating due to air in the stomach