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Gastric emptying and gastro-oesophageal reflux in preterm infants
A K Ewer1, G M Durbin, M E Morgan
1Institute of Child Health, University of Birmingham.
Insights
Gastro-oesophageal reflux is common in preterm infants. This study found that gastric emptying time does not determine reflux occurrence in these infants, suggesting other factors are involved.
Area of Science:
- Neonatal Medicine
- Gastroenterology
- Pediatric Physiology
Background:
- Gastro-oesophageal reflux is highly prevalent in preterm infants.
- The specific role of gastric emptying in this reflux has remained largely uninvestigated.
- Understanding reflux determinants is crucial for infant health management.
Purpose of the Study:
- To investigate the relationship between gastric emptying rates and gastro-oesophageal reflux in preterm infants.
- To determine if delayed gastric emptying contributes to reflux episodes.
- To explore potential factors influencing reflux in this vulnerable population.
Main Methods:
- Gastric emptying was measured using real-time ultrasound to assess antral cross-sectional area (ACSA) changes post-feed.
- Lower oesophageal pH was monitored for 24 hours using an antimony pH electrode.
- Half emptying time was calculated and correlated with reflux indices.
Main Results:
- No significant association was found between gastric emptying rates and gastro-oesophageal reflux indices.
- Reflux occurrence was independent of feed volume and type.
- Average half emptying time was 46 minutes (median range 18-105 minutes).
Conclusions:
- Gastric emptying time is not a determinant of asymptomatic gastro-oesophageal reflux in preterm infants.
- Factors such as lower oesophageal sphincter relaxation or oesophageal motility abnormalities are more likely causes.
- Further research should focus on these alternative mechanisms in preterm infant reflux.
Abstract:
Gastro-oesophageal reflux is common in preterm infants, but the role of gastric emptying as a causal factor has not been studied before. Gastric emptying was therefore measured in 19 healthy preterm infants (median gestational age 32 weeks) while concurrently measuring 24 hour lower oesophageal pH, using an antimony pH electrode, positioned manometrically. Real time ultrasonic images of the gastric antrum were obtained, and measurements of antral cross-sectional area (ACSA) were made immediately before a nasogastric feed and then during subsequent gastric emptying until ACSA returned to its pre-feed value. Half emptying time (50% delta ACSA) was calculated as the time taken for the ACSA to fall to half the maximal postprandial increment. Mean (SEM) reflux index for the group was 11.9 (2.0)%; number of reflux episodes per 24 hours: 15.4 (1.7); and number of reflux episodes longer than five minutes 5.5 (0.8). Average half emptying times for an individual infant were: median (range) 46 (18-105) minutes. There was no association between gastric emptying rates and any of the indices of gastro-oesophageal reflux, either during the entire 24 hour period for which the lower oesophageal pH was recorded, or in the postprandial periods after the feeds which were studied ultrasonically. Gastro-oesophageal reflux was also unrelated to feed volume and feed type. Asymptomatic gastro-oesophageal reflux is common in preterm infants, but gastric emptying time is not a determinant of it. Inappropriate relaxation of the lower oesophageal sphincter or abnormal oesophageal motility offer more plausible explanations.