Studies bowel preparation and colonoscopy safety in people with heart, kidney or liver disease

Patients will receive 1 L of PEG solution between 10 PM and 11 PM the day before and 1 L of PEG solution between 6 AM and 7 AM on the day of colonoscopy. Clear liquids will be allowed after the completion of the last bowel preparation until the start of the procedure. Liquid diet includes soups, fruit juices, rice kanji, or porridge in liquid consistency, and clear liquids such as coconut water and lemon juice.

After the adequacy of bowel preparation is deemed fit, the patients will be taken for colonoscopic examination. A single blinded outcome assessment will be done by the colonoscopist/endoscopist performing the procedure (adequacy of bowel preparation) and the endoscopy nurse (tolerability and compliance).

Colonoscopy will be performed using standard video colonoscopes (Olympus, Tokyo, Japan) between 11:00 AM and 1:00 PM without sedation. The colonoscopist / endoscopist will assess the adequacy of bowel preparation using the Boston Bowel Preparation Scale (BBPS). Excellent, good and poor bowel preparations will be defined by BBPS score of 9, 6 - 9 and < 6, respectively. (12-14) Blood sampling will be done before bowel preparation and after colonoscopy in all patients for measurement of baseline parameters, renal function status (Serum creatinine, serum urea), serum electrolytess (serum sodium, serum potassium, serum phosphate and serum calcium) and haematocrit.

Assessment of safety and tolerability will be performed using clinical examination and symptom questionnaire. Cardiovascular and gastrointestinal (GI) symptoms will be recorded. Cardiovascular symptoms such as dyspnea, palpitations, chest pain, will be recorded and scored using the NYHA classification system for symptom severity. Clinical examination will be carried out post-bowel preparation and post-procedure to assess for signs of fluid overload, i.e. auscultation for crepitations and measurement of JVP. GI symptoms such as nausea, abdominal pain, vomiting, dizziness, bloating, and headache will be recorded and scored on a 4-point scale: 1 = none, 2 = mild, 3 = moderate, and 4 = severe. The compliance of bowel preparation will be defined as "poor" for patients who consume less than 75% of the PEG preparation.