GASTRIC SECRETORY MATURATION OF PRETERM INFANTS

Abstract

To establish normative values for gastric secretory function in preterm infants we studied 34 healthy preterm infants: mean gestational age 30.6 wk (27-35 wk), mean birth wt 1.5 kg (range .82-2.46 kg). Basal acid output (BAO), post-pentagastrin (6 μg/kg, sc) maximal acid output (MAO) and fasting serum gastrin (SG) were measured. Infants were studied weekly a mean of 4.6 times (range 1-8 times). Results are expressed as mean ± SEM. At postnatal age 1 wk BAO was 12±3 μmole/Kg·hr; MAO was 21±4 μmole/Kg·hr (p<.01). Achlorhydria was present in 2 of 21 infants in week 1; both secreted acid by week 2. An increase BAO to 26±5 μmole/Kg·hr at 8 wk was dependent on postnatal age (p<.05). An increase in MAO to 53±7 μmole/Kg·hr at 8 wk was dependent on postnatal age (p<.01) and on postconceptual age (p<.01). Although SG increased with postnatal age from 64±9 pg/ml at 1 wk to 157±30 pg/ml at 8 wk (p<.01), there was no correlation between SG and BAO or MAO. BAO, MAO, and SG did not correlate with weight or sex. These results indicate that in healthy preterm infants 1) a response to pentagastrin is present at 1 wk of age 2) BAO equals normal values for term infants and children 2-4 wk after birth regardless of gestational age 3) BAO, MAO and SG increase over the first 8 wk of life and 4) BAO and SG are not influenced by gestational age. In healthy preterm infants 1) postnatal factors appear to be in part responsible for maturation of acid secretory function and 2) SG is not linked to maturation of gastric secretory function.