Gastric Emptying in Preterm Infants with pH Probe Positive Gastroesophageal Reflux

Abstract 1629 Poster Session III, Monday, 5/3 (poster 80)

BACKGROUND: Gastroesophageal reflux (GER) is a significant problem in premature infants and the relationship between gastric emptying and GER is unclear. The ¹³C-octanoic acid breath test is a novel, safe and practical investigation that allows accurate determination of gastric emptying. The aim of this study was to evaluate gastric emptying using the ¹³C-octanoic acid breath test in a population of preterm infants undergoing 24 hour pH probe, the current gold standard investigation for GER.

METHODS: Thirty-one preterm infants (24-35 weeks gestational age) were studied at a mean age of 30 days. Twenty-four hour pH monitoring was performed on each infant. Each infant then underwent assessment of gastric emptying using the ¹³C-octanoic acid breath test. To perform the breath test infants were given their normal milk or formula feed containing 1 uL/ml ¹³C labeled-octanoic acid. Octanoic acid is rapidly absorbed in the duodenum and metabolised to ¹³CO₂ which was measured in the breath. The time course of recovery of ¹³CO₂ allows calculation of gastric half emptying time (t1/2) and gastric emptying coefficient (GEC). Infants were divided into 2 groups based on pH probe results; "probe positive" infants were those with a reflux index (% time pH <4) of greater than 10%.

RESULTS: Nineteen infants were probe positive (mean reflux index 25%, range 11-55%). Probe negative infants had a mean reflux index of 5% (range 2-9%). Gastric emptying parameters were similar for infants with GER (probe positive) and those without (probe negative) (see table). There were no differences in feed type, volume or caloric strength between the 2 groups and no infants were on prokinetic medication at the time of being studied.

Table 1 No caption available

CONCLUSION: A large proportion of premature infants demonstrate abnormally high degrees of oesophageal acidification. Our data do not support a relationship between gastric emptying and acid gastro-oesophageal reflux in premature infants.