Gastric relaxation prior to enteral feeding.

The purpose of this investigation was to determine whether the observed gastric relaxation associated with the intragastric infusion of a liquid meal could be conditioned to the temporarily associated auditory cues to enteral feeding and thus produce decreased intragastric pressures under "sham" feeding conditions. Eight normal volunteers received either enteral feedings or sham feedings followed by enteral feedings on 72 separate trial days. The feedings were administered at a constant rate via a Harvard infusion pump. Intragastric pressure changes were monitored by an open tipped pressure cannula which was attached to the feeding tube. A sham feeding consisted of carrying out all preparatory procedures including activation of the feeding pump which was visually screened from the patient. Without the subjects' knowledge the liquid diet was diverted to another reservoir instead of through the nasogastric tube. This sham type infusion produced a gastric response similar to the response to a normal diet infusion as evidenced by a decrease in intragastric pressure and a suppression of irregular high amplitude contractions that are associated with hunger. This anticipatory response to enteral feeding indicative of prospective relaxation of the stomach may enhance the subsequent accommodation to a volume of diet. Additional studies are needed to investigate the importance of visual and auditory cues on patient tolerance of enteral feedings.