A colonoscopy is a medical procedure used to examine the entire length of the large intestine, or colon, using a long, flexible tube equipped with a camera. This examination is primarily performed for screening, allowing a physician to visually inspect the internal lining of the colon wall for any abnormalities. Its main purpose is the early detection and removal of precancerous growths called polyps, which helps prevent the development of colorectal cancer. The procedure can also be used to investigate symptoms like unexplained changes in bowel habits, chronic diarrhea, or rectal bleeding.
Understanding the Required Preparation
The preparation phase, often referred to as the “prep,” is the longest and most demanding part of the colonoscopy experience, and its complete adherence is necessary. The goal is to thoroughly cleanse the colon, ensuring the physician has a clear, unobstructed view of the intestinal lining during the examination. Inadequate preparation can obscure vision, potentially leading to missed polyps or the need to reschedule the entire procedure.
Preparation typically begins with a low-residue diet a few days before the procedure, followed by a strict clear liquid diet on the day before the examination. A clear liquid diet includes any fluid you can see through, such as water, clear broth, apple or white grape juice without pulp, and plain gelatin. Beverages like coffee or tea are allowed only without milk, cream, or non-dairy lighteners. You must avoid all solid foods and any liquids that are red, purple, or orange in color, as these dyes can stain the colon lining and be mistaken for blood.
The most active part of the prep involves drinking a prescribed bowel cleansing solution, which acts as a powerful laxative. This solution is often split into two doses: the first taken the evening before, and the second taken early the morning of the procedure. To make the large volume of solution more palatable, many patients find it helpful to chill the liquid or drink it through a straw to bypass the taste buds. The process will result in frequent, watery bowel movements, confirming that the colon is being properly cleaned for the examination.
Arrival and Pre-Procedure Steps
On the day of your colonoscopy, you will arrive at the clinic or hospital, having completed the bowel prep and fasted as instructed. After verifying paperwork, you will be escorted to a preparation area to change into a gown. Once settled, a nurse will place an intravenous (IV) line, typically in your arm or hand, which will be used to administer fluids and the sedation medication.
Before the procedure begins, you will meet the medical team, which generally includes the gastroenterologist who performs the procedure, a nurse, and an anesthesiologist or nurse anesthetist. The anesthesia provider reviews your medical history and discusses the type of sedation, most commonly monitored anesthesia care (MAC) or deep sedation utilizing propofol. This level of sedation ensures you are deeply relaxed and comfortable, or even completely asleep, throughout the examination. The team conducts final safety checks, confirming your identity and the procedure details before the sedation is administered.
The Experience During the Examination
The examination begins once the sedation takes effect, and most patients have no memory of the event. Deep sedation ensures you feel no pain during the 30-to-60-minute procedure. The physician inserts the colonoscope, a flexible tube with a tiny camera, through the rectum and gently guides it through the colon.
To get a clearer view of the colon walls, the doctor will insufflate the bowel with air or carbon dioxide (CO2), which gently expands the space. If the physician finds any polyps, they are removed immediately using tiny tools passed through the scope, a process that is entirely painless due to the lack of pain receptors in the colon lining. Carbon dioxide is often preferred for insufflation because it is absorbed by the body faster than regular air, which can reduce post-procedure bloating. The thoroughness of the examination depends significantly on how well the colon was cleaned during the preparation phase.
Immediate Recovery and Discharge
Immediately following the colonoscopy, you are moved to a recovery area where the nursing staff closely monitors your vital signs as the sedation begins to wear off. The most common sensation upon waking is grogginess, and you may feel bloated or experience mild cramping from the air or CO2 used to inflate the colon during the procedure. To help dissipate this gas and relieve the bloating, nurses will encourage you to pass gas before you are discharged.
The doctor will often speak with you in the recovery area to provide immediate preliminary findings, though you may not remember the conversation due to the lingering effects of the sedative. Any tissue samples or polyps removed are sent to a lab, and the final biopsy results are usually available within one to three weeks. Due to the medications administered, you are strictly prohibited from driving, operating heavy machinery, or signing legal documents for the rest of the day. A responsible adult must drive you home and is highly recommended to stay with you for the first 24 hours until the sedation effects have fully resolved.