Gastric tone variations during gastric infusion of fiber-supplemented formulas

Despite gastric feeding being a common method of artificial nutritional support, little is known about the effects of enteral nutrition on fundic motor function. The objective of this study was to assess variations of fundic tone and their relation to antroduodenal motility before, during and after nasogastric feeding supplemented or not with fibers.

Double-blinded studies were performed in random order with the three different diets (2100 kJ) in eight volunteers: fiber free (FF), insoluble fiber (IF) or mixed fiber (MF). Fundic tone was recorded by barostat concomitantly with antroduodenal manometry.

Before the infusion, seven spontaneous fundic relaxations occurred during the 24 studies. Concomitantly or less than 2 min before these relaxations, phase III of the migrating motor complex (MMC) with a duodenal onset was recorded. Only the 17 studies without spontaneous fundic relaxation (4 FF, 6 MF, 7 IF) were suitable for the assessment of fundic response to infusion. Disappearance of the volume waves at the beginning and during the whole infusion was observed in 11/17 studies (FF 50%, MF 66% and IF 71%, NS), but a proximal gastric relaxation following the beginning of the infusion occurred in only three individuals, one with the FF and two with IF. When it occurred, fundic relaxation was observed within 2 min and was not different from those observed spontaneously.

Gastric infusion of a polymeric diet, supplemented or not with fiber, did not promote fundic relaxation in most of the cases but often induced a disappearance of gastric volume waves.