| Abstract: | The lactulose breath test (LBT) andgastroenterocolonic scintigraphy (GECS) can both be usedto measure orocecal transit time (OCTT). The aims ofthis study were (1) to measure OCTT by LBT and GECS and (2) to determine whether lactulose altersorocecal transit. Methods: Eight normal subjectsunderwent simultaneous breath hydrogen testing, GECS,and duodenal manometry while receiving either 10 glactulose or placebo with a radiolabeled solid/liquidtest meal during two studies. There was a goodcorrelation between OCTT by LBT and GECS when performedsimultaneously (r = 0.95; P < 0.001). OCTT by GECSwith lactulose was significantly faster (P = 0.004) than byGECS without lactulose, despite no change in gastricemptying of liquids and slowing of gastric emptying ofsolids (P = 0.02). The postprandial duodenal motility index was greater with lactulose than withplacebo (P = 0.031). This study demonstrates that LBTand GECS (without lactulose) are not equivalent measuresof OCTT. The standard LBT accelerates OCTT and slows gastric emptying. Therefore, lactulose has adirect accelerating effect on small intestinaltransit. |
