Bowel preparation and the safety of colonoscopic polypectomy.

A fatal colonic explosion has been recorded during colonoscopic polypectomy after oral mannitol bowel preparation. It has been suggested that bacterial degradation of oral mannitol allows the production of hydrogen and methane which are potentially explosive. We have analyzed the gas composition of colonic aspirates in unprepared patients (n = 11), after orthograde saline lavage (n = 11), after oral mannitol alone (n = 11), and when oral mannitol was given with oral antibiotics (n = 11). After oral mannitol bowel preparation 7 patients had potentially explosive gas mixtures compared with 4 in the unprepared group, 1 after orthograde saline lavage, and none when oral antibiotics were used before mannitol. We believe, therefore, that if oral mannitol is used for bowel preparation before colonoscopic polypectomy oral antibiotics should also be administered or insufflation should be with carbon dioxide.