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Harvard Medical School

Colonoscopy

How It's Done

You will put on a hospital gown, and the doctor's assistant will record your vital signs, including temperature, pulse and blood pressure. A pulse oximeter (to measure the oxygen saturation level of your blood) may be placed on your finger, ear or toe, and electrocardiograph (EKG) recording patches will be placed on your chest to monitor your heartbeat. You will be asked to lie on your side on an examination table, with the lower portion of your body covered by a sheet. As your doctor directs, you may be asked to raise one or both of your knees up to your chest. You will be given medication that will lightly sedate you and help your doctor insert a lubricated, flexible colonoscope into your rectum and, as necessary, pump a small amount of air through the colonoscope to open up your intestinal passage for a clearer view. Your doctor may also take a stool sample or biopsy from inside your bowel.