VOL: 99, ISSUE: 20, PAGE NO: 29
WHAT IS IT?
- Colonoscopy is an investigation that uses a flexible, fibre-optic endoscope to examine the rectum, colon and terminal ileum. It is usually performed in an outpatient clinic, under light sedation.
- Videoscopes are now used, whereby a camera-imaging tip sends pictures to a high-resolution television screen.
WHY IS IT PERFORMED?
- As a diagnostic tool for patients with symptoms such as lower gastrointestinal bleeding, change in bowel habit or abdominal pain.
- To evaluate or follow up inflammatory bowel disease.
- To screen for polyps or colorectal cancer.
- For interventions such as removal of foreign bodies, polypectomy, stricture dilatation and stenting (for example of a malignancy).
- Contraindications: acute colitis/diverticulitis, severe cardiac and chest complaints, abnormal coagulation, liver cirrhosis, pregnancy.
- Take a full medical history from the patient.
- Explain the procedure and gain informed consent.
- The bowel is cleared before the procedure and the patient should be given full instructions regarding the medication used for this purpose.
- The patient may be on free fluids only or a light diet the day before.
PERFORMING A COLONOSCOPY
- The patient is cannulated.
- Sedation and analgesia, such as intravenous midazolam and pethidine, is given in incremental doses.
- The patient is positioned in the left lateral position.
- The endoscopist performs a digital, rectal examination.
- The endoscope is lubricated and inserted into the anus.
- It is guided along the lumen of the rectum and colon using a variety of methods: torsion, withdrawal, twisting and untwisting.
- Nursing staff assist in moving the patient or applying abdominal pressure to help the endoscope move forward.
- Once the whole colon has been viewed, the endoscope is removed slowly, allowing full visualisation again on withdrawal. Biopsies may be taken during removal.
- Polyps may be identified and removed using a snare and electrocautery.
DURING THE PROCEDURE
- Monitor the patient’s level of consciousness and physiological signs (such as heart rate and oxygen saturation).
- Ensure resuscitation equipment and reversal agents are to hand.
- Observe the patient’s tolerance of the procedure, for example, pain.
- Provide reassurance, commentary and support.
- Watch out for unexpected events such as vomiting, cardiorespiratory depression and vasovagal reactions.
- Document time, dosage and route of all medications.
- Assess and document patient’s status on completing the procedure.
AFTER THE PROCEDURE
- Assess and monitor the patient until he or she has fully recovered.
- Document all care given and any unusual events that occurred.
- Provide written instructions regarding diet, medications, activity restrictions, follow-up and complications.
- Make sure the patient is accompanied home.
- Major complications: colonic perforation, haemorrhage, over-sedation, cardiorespiratory events, septicaemia.
- Minor complications: incomplete procedure due to abdominal discomfort, rectal bleeding.