Endoscopes are electro-optical devices that are used to visualize the internal body cavities. The specialized endoscopic procedure of the upper gastrointestinal tract from the esophagus down to the duodenum is called an esophagogastroduodenoscopy (EGD). EGD visualizes the upper part of the gastrointestinal tract. During the EGD, a flexible hose with a small video camera, lighting, and other special components is inserted through the patient’s mouth or nose. The diameter of the endoscope hose ranges from $\sim 6$ to 10 mm. EGD is usually done when the patient is in the left lateral position, and it can be performed without sedation, using only topical anesthesia, or under sedation, which generally results in better patient tolerance and comfort.