Colonoscopy: Indications, Procedure Nursing Assessment by NJE


Colonoscopy: To visualize and assess the lower colon for tumor, cancer, and infection.

PATIENT PREPARATION: Inform the patient that a laxative and cleansing enema may be needed the day before the procedure, with cleansing enemas on the morning of the procedure, depending on the institution’s policy. Instruct the patient that to reduce the risk of aspiration related to nausea and vomiting, solid food and milk or milk products are restricted for at least 6 hr, and clear liquids are restricted for at least 2 hr prior to general anesthesia, regional anesthesia, or sedation/analgesia (monitored anesthesia). The patient may be asked to be NPO after midnight. The American Society of Anesthesiologists has fasting guidelines for risk levels according to patient status.

Patients on beta-blockers before the surgical procedure should be instructed to take their medication as ordered during the perioperative period.

Regarding the patient’s risk for bleeding, the patient should be instructed to avoid taking natural products and medications with known anticoagulants, antiplatelet, or thrombolytic properties or to reduce dosage, as ordered, prior to the procedure. Number of days to withhold medication is dependent on the type of anticoagulant. Note the last time and dose of medication taken.

Patients on beta-blockers before the surgical procedure should be instructed to take their medication as ordered during the perioperative period. Protocols may vary among facilities.

Ensure that this procedure is performed before an upper gastrointestinal (GI) study or barium swallow to avoid interference from retained barium. If a computed tomography (CT) scan is requested, ensure that barium studies were performed more than 4 days before the CT scan.



Normal intestinal mucosa with no abnormalities of structure, function, or mucosal surface in the colon or terminal ileum.


OVERVIEW: (Study type: Endoscopy; related body system: Digestive system.) Colonoscopy, a radiological examination of the colon, follows the instillation of barium (single contrast study) using a rectal tube inserted into the rectum. The patient retains the contrast while a series of images are obtained, recorded, and available for viewing. Visualization can be improved by draining the barium and using air contrast (double-contrast study); some of the barium remains on the surface of the colon wall, allowing for greater detail in the images. A combination of x-ray and fluoroscopic techniques are used to allow inspection of the mucosa of the entire colon, ileocecal valve, and terminal ileum using a flexible fiberoptic colonoscope inserted through the anus and advanced to the terminal ileum. The colonoscope, a multichannel instrument, allows viewing of the GI tract lining, insufflation of air, aspiration of fluid, collection of tissue biopsy samples, and passage of a laser beam for the obliteration of tissue and control of bleeding. Mucosal surfaces of the lower GI tract are examined for ulcerations, polyps, chronic diarrhea, hemorrhagic sites, tumors, and strictures. During the procedure, tissue samples may be obtained for cytology, and some therapeutic procedures may be performed, such as excision of small tumors or polyps, coagulation of bleeding sites, and removal of foreign bodies. CT colonoscopy may be indicated for patients who have diseases rendering them unable to undergo conventional colonoscopy (e.g., bleeding disorders, lung or heart disease) and for patients who are unable to undergo the sedation required for traditional colonoscopy.


• Assess GI function in a patient with a personal or family history of colon cancer, polyps, or ulcerative colitis.

• Confirm diagnosis of colon cancer and inflammatory bowel disease.

• Detect Hirschsprung disease and determine the areas affected by the disease.

• Determine cause of lower GI disorders, especially when barium enema and proctosigmoidoscopy are inconclusive.

• Determine source of rectal bleeding and perform hemostasis by coagulation.

• Evaluate the postsurgical status of colon resection.

• Evaluate stools that show a positive occult blood test, lower GI bleeding, or change in bowel habits.

• Follow up on previously diagnosed and treated colon cancer.

• Investigate iron-deficiency anemia of unknown origin.

• Reduce volvulus and intussusception in children.

• Remove colon polyps.

• Remove foreign bodies and sclerosing strictures by laser.


Contraindication of Colonoscopy

Patients with bleeding disorders or cardiac conditions.

Patients with bowel perforation, acute peritonitis, acute colitis, ischemic bowel necrosis, toxic colitis, recent bowel surgery, advanced pregnancy, severe cardiac or pulmonary disease, recent myocardial infarction, known or suspected pulmonary embolus, and large abdominal aortic or iliac aneurysm.

Patients who have had a colon anastomosis within the past 14 to 21 days, because an anastomosis may break down with gas insufflation.

Factors that may alter the results of the study

• Gas or feces in the GI tract resulting from inadequate cleansing or failure to restrict food intake before the study.

• Retained barium from a previous radiological procedure.

• Severe lower GI bleeding or the presence of feces, barium, blood, or blood clots, which can interfere with visualization.

• Spasm of the colon, which can mimic the radiographic signs of cancer. (Note: The use of IV glucagon minimizes spasms.)

• Inability of the patient to tolerate the introduction of or retention of barium, air, or both in the bowel.

• Metallic objects (e.g., jewelry, body rings) within the examination field, which may inhibit organ visualization and cause unclear images.

Other considerations 

• Bowel preparations that include laxatives or enemas should be avoided in pregnant patients or patients with inflammatory bowel disease unless specifically directed by a healthcare provider (HCP).



Abnormal findings related to

• Benign lesions

• Bleeding sites

• Bowel distention

• Bowel infection or inflammation

• Colitis

• Colon cancer

• Crohn disease

• Diverticula

• Foreign bodies

• Hemorrhoids

• Polyps

• Proctitis

• Tumors 

• Vascular abnormalities.


Teaching the Patient What to Expect

➧ Inform the patient this procedure can assist in assessing the colon for disease.

➧ Explain that prior to the procedure, laboratory testing may be required to determine the possibility of bleeding risk (coagulation testing) or to assess for impaired kidney function (creatinine level and estimated glomerular filtration rate) if use of iodinated contrast medium is anticipated.

➧ Review the procedure with the patient. Address concerns about pain and explain that there may be moments of discomfort or pain experienced when the IV line or catheter is inserted to allow infusion of fluids such as saline, anesthetics, sedatives, medications used in the procedure, or emergency medications; explain that there may be moments of discomfort during the procedure.

➧ Inform the patient that the procedure is performed in a GI laboratory, by an HCP, with support staff, and takes approximately 30 to 60 min.

➧ Baseline vital signs will be recorded and monitored throughout the procedure. Protocols may vary among facilities.

➧ Medications will be administered, as ordered, to reduce discomfort and to promote relaxation and sedation. Positioning for the study is on an examination table in the left lateral decubitus position, draped with the buttocks exposed. Explain that the HCP will initially perform a visual inspection of the perianal area and a digital rectal examination. Tell the patient he or she will be asked to bear down as if having a bowel movement as the fiberoptic tube or colonoscope (scope) is inserted through the rectum.

➧ Explain that the scope is advanced through the sigmoid and the patient’s position is changed to supine to facilitate passage into the transverse colon. Advise the patient that he or she will be asked to take deep breaths to aid in the movement of the scope downward through the ascending colon to the cecum and into the terminal portion of the ileum. Air is insufflated through the tube during passage to distend the GI tract, as needed, which aids in visualization. Biopsies, cultures, or any endoscopic surgery is performed. Foreign bodies or polyps are removed and placed in appropriate specimen containers, labelled, and sent to the laboratory. Images are obtained for future reference. At the end of the procedure, excess air and secretions are aspirated through the scope, and the colonoscope is removed.

Potential Nursing Actions

Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.

➧ Note intake of oral iron preparations within 1 wk before the procedure because these cause black, sticky feces that are difficult to remove with bowel preparation.

Safety Considerations

➧ Anticoagulants, aspirin, and other salicylates should be discontinued by medical direction for the appropriate number of days prior to a procedure where bleeding is a potential complication.


Avoiding Complications

➧ Complications of the procedure may include bleeding and cardiac dysrhythmias. Instruct the patient to immediately report symptoms such as fast heart rate, difficulty breathing, skin rash, itching, chest pain, or abdominal pain. 

Treatment Considerations

➧ After the procedure, monitor vital signs and neurological status every 15 min for 1 hr, then every 2 hr for 4 hr, or as ordered. Monitor the patient for signs of respiratory depression. Take temperature every 4 hr for 24 hr. Monitor intake and output at least every 8 hr. Compare with baseline values. Notify the HCP if the temperature is elevated. Protocols may vary among facilities.

➧ Observe the patient until the effects of the sedation have worn off. Carefully monitor the patient for fatigue and fluid and electrolyte imbalance. Instruct the patient to resume usual diet, fluids, medications, and activity, as directed by the HCP.

➧ Monitor for any rectal bleeding. Instruct the patient to expect slight rectal bleeding for 2 days after removal of polyps or biopsy specimens but that an increasing amount of bleeding or sustained bleeding should be reported to the HCP immediately.

➧ Advise the patient that belching, bloating, or flatulence is the result of air insufflation. 

➧ Encourage the patient to drink several glasses of water to help replace fluids lost during the preparation for the test.

Follow-Up, Evaluation, and Desired Outcomes

➧ Recognizes cancer screening options and understands that decisions regarding the need for and frequency of occult blood testing, colonoscopy, or other cancer screening procedures may be made after consultation between the patient and HCP. The American Cancer Society (ACS) screening recommendations regarding regular screening for colon cancer begins at age 50 yr for individuals with average risk and sooner for those with increased or high risk for developing colon cancer. Its recommendations for frequency of screening are to use one of the following:

Tests That Can Identify Polyps and Cancer

➧ Colonoscopy every 10 yr

➧ CT colonography (virtual colonoscopy) every 5 y.

➧ Flexible sigmoidoscopy every 5 yr

➧ Double-contrast barium enema every 5 yr.

Tests That Primarily Identify Cancer

➧ Fecal immunochemical test (FIT) annually

➧ Fecal occult blood test (guaiac-based) annually

➧ Stool DNA test every 3 yr.

Reference Davis laboratory and Diagnostic test


Please enter your comment!
Please enter your name here