A comparison of two methods of whole gut lavage for colonoscopy

Abstract

Summary Two forms of bowel preparation for colonoscopy were compared—19 patients were given 5 per cent mannitol solution orally while a further 19 were infused with isotonic saline via a nasogastric tube. Both methods proved equally acceptable to the patients and endoscopists. Saline led to a rise in body weight (+0·75±0·35kg) and blood pressure (+7·5±2·8 mmHg) while mannitol caused a significant fall in both body weight (−0·74±0·28 kg) and blood pressure (−3·8±2·9 mmHg). Plasma volume measurements were carried out on 17 patients; 8 receiving saline showed a rise (+0·22±0·08l) while 9 taking mannitol experienced a fall (−0·17±0·08l). Twelve further subjects prepared with a combination 10 per cent mannitol and isotonic saline showed a small fall in plasma volume (−0·08±0·05l). Mannitol proved an acceptable preparation for colonoscopies but a fall in body weight, blood pressure and plasma volume posed a small risk to the elderly subject and in view of the known risks of mannitol during diathermy this form of preparation was not considered a suitable alternative to isotonic saline.