Colonoscopy uses a flexible fiberoptic colonoscope inserted through the rectum to examine the lining of the large intestine. It is indicated for a history of constipation, diarrhea, persistent rectal bleeding, or lower abdominal pain when proctosigmoidoscopy and barium enema results are negative or inconclusive.
You prep the bowel, obtain informed consent, ease anxiety, and keep the patient safe before, during, and after. You also protect the next patient: reprocessing the scope (cleaning, disinfection, sterilization) prevents patient-to-patient infection. Wipe the scope tube with a lint-free cloth soaked in detergent solution, then send it to the sterile reprocessing room for cleaning, leak testing, visual inspection, and sterilization.
Indication
- Screen for colon and rectal cancer. The U.S. Preventive Services Task Force recommends average-risk screening start at age 45 and continue through 75, and colonoscopy remains a preferred screening test.
- Detect and evaluate inflammatory and ulcerative bowel disease
- Locate the source of lower GI bleeding and achieve hemostasis by coagulation
- Determine the cause of lower GI disorders when barium and proctosigmoidoscopy results are inconclusive
- Diagnose colonic strictures and benign or malignant lesions
- Evaluate the colon postoperatively for recurrence of polyps and malignant lesions
- Investigate iron-deficiency anemia of unknown origin
- Remove colon polyps
- Remove foreign objects and sclerose strictures by laser
Contraindication
- Pregnant women near term
- Bleeding disorders
- Recent acute myocardial infarction or abdominal surgery
- Ischemic bowel disease, acute diverticulitis, peritonitis, fulminant granulomatous colitis, perforated viscus, or fulminant ulcerative colitis. For these cases or for screening, virtual colonoscopy may help visualize polyps before they become concerns.
Procedure
- The patient lies on the left side with knees flexed and draped.
- Baseline vital signs are obtained and monitored throughout. With known cardiac disease, run continuous ECG monitoring. Continuous or periodic pulse oximetry is advisable, especially in the high-risk patient at risk for respiratory depression from sedation.
- The patient breathes deeply and slowly through the mouth as the practitioner palpates the anus and rectum and inserts the lubricated colonoscope under direct vision through the anus into the sigmoid colon.
- A small amount of air is insufflated to locate the bowel lumen, then the scope is advanced through the rectum.
- At the descending sigmoid junction, the patient is moved to supine to aid advancement if needed. Past the splenic flexure, the scope advances through the transverse colon, through the hepatic flexure, and into the ascending colon and cecum.
- Abdominal palpation or fluoroscopy may help guide the scope through the large intestine.
- Suction removes blood and secretions that obscure the view.
- Biopsy forceps or a cytology brush is passed through the scope for histologic or cytologic specimens. An electrocautery snare may remove polyps.
- A tissue specimen is placed immediately in a bottle of 10% formalin. Cytology smears go immediately into a Coplin jar of 95% ethyl alcohol. Specimens are sent to the lab immediately.
Interfering Factors
- Insufficient bowel prep or failure to restrict food intake beforehand
- Retained barium from a previous diagnostic procedure
- Inability to tolerate or retain barium, air, or both in the bowel
- Sigmoid colon fixation from inflammatory bowel disease, surgery, or radiation that hinders passage of the scope
- Blood from acute colonic hemorrhage that interferes with visualization
- Colon spasms that mimic the radiographic signs of cancer
Nursing Responsibilities
Before the procedure
- Secure informed consent. Confirm the patient or surrogate has signed.
- Obtain a medical history. Check allergies, bleeding history, medications, and details relevant to the complaint.
- Explain the procedure. Tell the patient colonoscopy examines the lining of the large intestine, who performs it, and where.
- Confirm bowel prep compliance. The bowel must be thoroughly clean to be visible. The patient maintains a clear-liquid diet for 24 to 48 hours before the test, takes nothing by mouth after midnight the night before, and takes a laxative as ordered or 1 gallon of GoLYTELY solution in the evening (drinking the chilled solution at 8 oz [236.6 ml] every 10 minutes until the entire gallon is consumed).
- Establish an IV line. A sedative is given before the procedure, so the patient must arrange a ride home.
- Provide reassurance. The scope is well lubricated, feels cool at first, and may bring an urge to defecate as it advances.
- Explain air insufflation. Air distends the intestinal wall to aid viewing and advancement. Flatus escapes around the instrument, and the patient should not try to hold it.
- Have the patient void. Voiding immediately before the procedure is more comfortable. The patient changes into the gown, robe, and foot coverings.
- Remove metallic objects from the field. Jewelry can alter visualization and blur images.
- Instruct the patient to stay still. Movement creates unreliable results.
During the procedure
- Assist with positioning. Left lateral decubitus with a sheet draped over the body.
- Administer medications as ordered. Pain medication and sedative reduce discomfort and promote relaxation.
- Instruct the patient to bear down. Bearing down as if having a bowel movement helps as the tube enters the rectum.
- Reposition as the scope advances. Move the patient to supine past the sigmoid to allow passage into the transverse colon. Air is insufflated to aid visualization.
- Encourage slow, deep breaths. This eases scope movement through the ascending colon to the cecum and into the terminal ileum.
After the procedure
- Watch for bowel perforation. Report severe abdominal pain, nausea, vomiting, fever, and chills immediately.
- Record vital signs. Monitor vital signs and neurologic status every 15 minutes for 1 hour, then every 2 hours for 4 hours, or as ordered. Check temperature every 4 hours for 24 hours.
- Resume diet and activity as ordered. Once recovered from sedation, the patient returns to usual diet and activity unless told otherwise.
- Provide privacy to rest. Large amounts of flatus may pass after insufflation.
- Monitor for rectal bleeding. After polyp removal, minimal bleeding is expected for 2 days. Report an increasing amount immediately.
- Encourage fluids. Fluids replace what was lost during prep.
Normal Results
- Light-pink-orange mucosa of the large intestine beyond the sigmoid colon, marked by semilunar folds and deep tubular pits
- Visible blood vessels beneath the intestinal mucosa, glistening from mucus secretions
Abnormal Results
- Benign or malignant lesions
- Bowel inflammation and ulceration
- Granulomatous or ulcerative colitis
- Colonic polyps
- Crohn's disease
- Diverticular disease or the site of lower GI bleeding
- Hemorrhoids
- Proctitis
- Tumors
- Vascular abnormalities
Frequently Asked Questions
At what age should average-risk adults start colonoscopy screening? The USPSTF and the American Cancer Society recommend average-risk screening begin at age 45 and continue through 75. Adults 76 to 85 should decide with their provider, and those at higher risk may start earlier.
Why is the bowel prep so important? The colon lining must be clean for the scope to see the mucosa. Retained stool hides polyps and lesions and often forces the test to be repeated, so prep compliance is a core nursing responsibility.
Why does the patient need a ride home? A sedative is given before the procedure, so the patient cannot safely drive afterward and must arrange transportation.
Is some bleeding normal after a colonoscopy? After polyp removal, minimal rectal bleeding for up to two days is expected. Report increasing or heavy bleeding immediately, since it can signal a complication.
What are the most serious complications to watch for? Bowel perforation and hemorrhage. Report severe abdominal pain, nausea, vomiting, fever, and chills right away, and monitor vital signs closely during recovery.
How often is colonoscopy repeated? For average-risk adults with a normal result, colonoscopy is typically repeated every 10 years, though the interval shortens if polyps are found or risk factors are present. The provider sets the schedule based on findings.