The procedure may be performed in either a hospital or a clinic setting. A sedative or anesthetic may be administered intravenously prior to an esophagoscopy, gastroscopy, upper gastrointestinal endoscopy, or colonoscopy. The air that is pumped into the digestive tract during endoscopy sometimes causes discomfort, and sedation can reduce the unpleasant feeling. Some patients also may react to any anesthesia that is given. The patient’s breathing, blood pressure, heart rate and oxygen level will be closely monitored to ensure safety.

Patients who undergo an upper endoscopy may receive a spray or gargle solution with an agent that numbs the throat. This can help prevent the patient from gagging when the endoscope is inserted.

The procedure will unfold differently depending on the type of endoscopy being performed. During an upper endoscopy, patients are placed on their left side and a plastic mouthpiece is positioned between the teeth. This props the mouth open, making it easier to insert the tube. The endoscope is lubricated, and the patient is asked to swallow it. Any saliva that builds up is suctioned away with a suction tube. The physician inspects the lining of the esophagus, stomach and small intestine using high-quality images captured by the endoscope that are projected onto a monitor or viewed directly through an eyepiece. If necessary, tissue samples are removed for biopsy or foreign bodies and polyps are cut away. The procedure usually takes 10 to 15 minutes.

During an endoscopy of the lower GI tract, patients are also placed on their left side. The physician then lubricates the endoscope and inserts it into the anus. The physician studies images of the colon and rectum walls that are transmitted to a monitor and performs any necessary surgery. Patients may be asked to change position to assist the physician in moving the endoscope. The procedure usually takes 15 to 60 minutes to complete.