Effect of caloric density on gastric emptying in premature infants.

The role of caloric density in the regulation of gastric emptying has been well documented in adults but studied to only a limited extent in young infants. Ten premature infants were each fed 22 ml/kg formula (Similac Special Care), at concentrations of 24, 20, 13, and 6.5 Cal/oz, as well as one feeding of distilled water. The volume of gastric contents was measured at 20-minute intervals by the double-aspiration technique using the marker polyethylene glycol 4000. Analysis of variance demonstrated a significant inhibition of gastric emptying related to increasing caloric density (P less than 0.001) when evaluated over the entire time of measurement. By 20 minutes, significant differences (P less than 0.01) were present between 0 and 6.5, 6.5 and 13, and 13 and 20 Cal/oz. A volume difference between 20 and 24 Cal/oz (P less than 0.05) was present only at 80 minutes. Despite the inhibition of emptying, higher caloric density feedings were associated with emptying of more calories over comparable periods (P less than 0.001). Regulation of gastric emptying by caloric density in premature infants is qualitatively similar to that in adults.