DUODENUM AS AN IMMEDIATE BRAKE TO GASTRIC OUTFLOW - A VIDEOFLUOROSCOPIC AND MANOMETRIC ASSESSMENT

Background & Aims: Duodenal infusion of HCl or lipid delays gastric em ptying. The aim of this study was to assess whether this delay was in part caused by mechanical activity of the duodenum. Methods: Synchroni zed videofluoroscopy and manometry was used in 8 volunteers (5 men and 3 women) to examine contractile and flow patterns during duodenal inf usion of 0.9% NaCl, HCl, 5% NaCl, bile, and sodium oleate, each mixed with 20% (wt/vol) barium sulfate. Results: Within 15-30 seconds of inf usion, HCl and 5% NaCl induced frequent large-amplitude contractions g reater than those induced by 0.9% NaCl. Initially, there was rapid dis persion of HCI followed by prolonged, tonic occlusion of the duodenum. The duodenal diameter decreased compared with that observed during 0. 9% NaCl or oleate infusion. In contrast, after infusion of oleate or b ile, duodenal diameter increased and there were fewer, smaller-amplitu de, nonpropagating contractions with prolonged retention of solutions. Barium (20%; wt/vol) did not influence the motility index of any solu tion. Conclusions: HCl and 5% NaCl may restrict gastric outflow by ind ucing tonic occlusion of the duodenum, whereas bile and lipid may dela y clearance by decreasing duodenal tone and contractility. Thus, the d uodenum may serve as an immediate brake to gastric outflow either by d elaying clearance or by offering rapid tonic resistance.