ANTRAL AND DUODENAL MOTOR-RESPONSES TO DUODENAL FEEDING IN PRETERM AND TERM INFANTS

In the fasting state, antral motor activity is similar in preterm and term infants, but the antral responses to feeding have not been compared in preterm and term infants. The purpose of this study was to use low-compliance, continuous perfusion manometry to compare antral and duodenal feeding responses in 13 preterm and nine term infants within the first 14 days of life. Confirming our previous studies, fasting antral motor activity was similar in preterm and term infants, but duodenal activity differed. Individual duodenal cluster activity was of shorter duration in preterm than in term infants (p < 0.01). Motor activity in antrum and duodenum changed in both groups of infants in response to an intraduodenal milk infusion of 4 ml/kg/2 h; however, the nature of the change varied in the two regions. In term infants, the number of antral pressure waves, the duration of antral clusters, and the antral motility index decreased by one third or more during feeding when compared with fasting (all p < 0.05). In contrast to the decrease in antral activity in response to feeding, the duodenal motility index and cluster activity increased significantly during feeding compared with fasting (both p < 0.05). The divergent response of antral and duodenal motor activity in response to feedings was also seen in preterm infants. Antral pressure waves, the duration of antral clusters, and the antral motility index were decreased during feeding (all p < 0.005 or less). Conversely, the preterm duodenal motility index and the duration of cluster activity increased during feeding compared with fasting (p < 0.05 or more). The suppression of antral motor activity in response to feeding is dissimilar to that described in adults fed solids and may be nutrient related. Since these antral responses occurred in response to duodenal feedings, they may have been mediated by hormones or local reflexes that are intact as early as 26 weeks' gestation.