Major points:
  1. You must fast for at least 8 hours before gastroscopy.
  2. You must have dentures removed before gastroscopy.
  3. You must wait 1 hour after the gastroscopy for food intake. Have small sips of water first to make sure that the swallowing reflex of your throat has been restored before eating.


I. What is gastroscopy?

Gastroscopy is the insertion of an electronic endoscope catheter into the stomach to transmit the internal image of the digestive tract and display it on a screen. The esophagus, stomach, and duodenum can be directly observed for abnormal lesions, such as inflammation, ulcers, bleeding, tumors, and polyps. If necessary, a pathological biopsy can be performed directly, or treatments, such as injection, ablation, and laser, can be performed. Painless gastroscopy is an intravenous injection of sedative and sleeping medications to achieve a sedative effect on the patients.


II. Preparation before examination:

  1. You must not eat any food, drink water, and take medicines for at least 8 hours.
  2. The physician will explain to you and ask you to fill out the “Upper Gastrointestinal Endoscopy and Treatment Consent Form.”
  3. You need to urinate before the gastroscopy and remove any removable dentures.
  4. If you are allergic to drugs or have a history of glaucoma, heart or lung disease, or are taking anticoagulants, then you need to inform your physician in advance to avoid drug allergy and the risk of bleeding during the gastroscopy.
  5. Those who receive painless gastroscopy at their own expense should complete an anesthesia risk assessment by an anesthesiologist after completing a chest X-ray and electrocardiogram before the gastroscopy.
  6. If you need to apply for painless gastroscopy, then you may ask your physician to perform it after the anesthesiologist’s assessment and approval. Currently, painless gastroscopy is at your own expense.


III. Examination procedure:

  1. Before the gastroscopy, the examination room staff will administer Buscopan, an intramuscular smooth muscle relaxant, to the patient.
  2. At the time of gastroscopy, the patient will first swallow a mouthful of Gascon drops to reduce flatulence. The reduction of abdominal distension facilitates gastroscopy.
  3. The examination room staff will first spray the anesthetic in the throat of the patient, who is requested to hold it for 1-2 minutes and not to spit it out.
  4. During the gastroscopy, the patient lies on the left side with a mouthpiece in the mouth to avoid biting the endoscope tube.
  5. The physician slowly inserts the gastroscope into the stomach from the patient’s mouth. During the insertion, the patient should take a deep breath to relax. When the tube reaches the throat, the patient should follow the instructions to swallow. If the patient feels like vomiting during the process, then the patient may take a deep breath to relieve discomfort.
  6. The gastroscopy usually takes approximately 15 to 20 minutes. The time may vary slightly depending on the purpose of the gastroscopy.


IV. Precautions after examination:

  1. If you experience any discomfort, such as abdominal pain or vomiting, after the gastroscopy, then please inform the healthcare staff immediately.
  2. After the gastroscopy, the physician will evaluate whether you can eat. With a positive confirmation for food intake from the physician, please wait 1 hour after the gastroscopy for the throat swallowing reflex to recover before eating. You may try a sip of water first. If there is no choking or other discomforts, then it means that the laryngeal reflex has recovered, and you may proceed with eating. You may also rinse your mouth with water to eliminate the anesthetics in your mouth as soon as possible.
  3. After the gastroscopy, there may be occasional pain and discomfort in the throat, which will disappear in about 2~3 days. You may rinse your mouth with normal saline or ice water to reduce the discomfort.
  4. Those who receive painless gastroscopy will wake up within 5 to 10 minutes after anesthesia. Common reactions are dizziness and drowsiness. These patients are not suitable for driving and doing other meticulous work on that day.



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  2. Kamel, Walid & AA, Elbaz. (2020). Sedation for upper gastrointestinal endoscopy, whatever the agents does it matter. International Journal of Anesthesiology & Research, 1-5.
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  4. Wu, L. B., Chou, H. L. (2020). Nursing Care for Digestive System Diseases. Liu, H. E. Chief Editor. Adult Medical and Surgical Care (8th Edition, 318–319). Farseeing Publishing Group.
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