Overview of colonoscopy in adults

Successful colonoscopy relies on effective bowel preparation to clear the colon of faeces. Poor bowel preparation may result in failure to detect adenomas and colorectal carcinoma—this should be explained to the patient to encourage bowel preparation adherence. The procedure may need to be repeated if bowel preparation is inadequate, which adds to cost and inconvenience of the colonoscopy.

The ideal bowel preparation for colonoscopy is well tolerated, safe and reliably clears the colon of all contents. Bowel preparation generally includes a period of dietary restriction and use of an oral lavage solution. Patients should be given oral and written instructions for the preferred regimen. Elderly or frail patients may need to be admitted to hospital for observation during bowel preparation.

The Australian Commission on Safety and Quality in Healthcare Colonoscopy Clinical Care Standard outlines evidence-based recommendations for high-quality care, including the use of bowel preparation and documentation of the procedure.The Standard specifies that the colonoscopy report should document:

• adequacy of the bowel preparation—poor preparation means pathology may not be visible
• whether caecal intubation was achieved—if the caecum is not seen pathology may be missed
• pathology found
• details of polyps removed, including how they were removed and whether they were retrieved
• adverse events (eg postpolypectomy bleeding)
• withdrawal time (duration between the time at which the caecum was reached and the time at which the instrument was removed from the colon)—this should be at least 6 minutes from caecum. A longer withdrawal time from caecum is associated with an increased adenoma detection rate and a lower incidence of interval colorectal carcinoma (a tumour diagnosed in the period between colonoscopies).

For children requiring a colonoscopy, seek expert advice about preparation requirements (including bowel preparation and fasting).