DUODENAL MOTOR-RESPONSES IN PRETERM INFANTS FED FORMULA WITH VARYING CONCENTRATIONS AND RATES OF INFUSION

Feeding intolerance is frequently reflected in preterm infants by dela yed gastric emptying, Gastric emptying is delayed by the physical char acteristics of ingested nutrient as well as the rate of feeding. Becau se gastric emptying is dependent upon duodenal function, the present s tudies were undertaken to assess duodenal motor responses to feeding o f differing nutrient content and rate of feeding. Using a Latin Square design we recorded duodenal motor responses in 14 preterm infants giv en four test feedings in random order over 18 h. Three were given as a 120-min infusion containing no nutrient a 10 cal/oz formula, and a 20 cal/oz formula. The fourth test feeding consisted of a 20 cal/oz form ula given as a bolus over 15 min. Although caloric density was altered , osmotic load and nutrient proportions of the formulas were not. Moto r responses were recorded using a low compliance continuous perfusion manometric system. When infants were fed ''water'' and half-strength f ormula as a slow infusion, they demonstrated little or no duodenal mot or response to feeding. When;these infants were fed full-strength form ula as a slow infusion, they displayed a brisk increase in motor activ ity (p < 0.05), but profound motor quiescence when fed the same volume by bolus over 15 min (p < 0.05). Of the. four test feedings, only ful l-strength formula given as a slow infusion triggered adult-like duode nal motor responses to feeding. We speculate that feedings of full-str ength formula given slowly by infusion will improve feeding tolerance.