After you receive sedatives, your endoscopist will pass the ultrasound endoscope through your mouth, esophagus and stomach into the duodenum. The instrument does not interfere with your ability to breathe. The actual examination generally takes less than 60 minutes. Many do not recall the procedure. Most patients consider it only slightly uncomfortable, and many fall asleep during the procedure.
An EUS examination of the lower gastrointestinal tract can often be performed safely and comfortably without medications, but you'll receive a sedative if the examination will be prolonged or if the doctor will examine a significant distance into the colon. You will start by lying on your left side with your back toward the doctor. Most EUS examinations of the rectum generally take less than 45 minutes. You should know that if a needle biopsy of a lesion or drainage of a cyst is performed during the EUS, then the procedure will be longer and may take up to two hours.