ABSTRACTS: Oral Presentation Abstracts
Introduction: Combined manometry and impedance greatly enhances the capabilities for evaluation of mechanisms of gastroesophageal reflux (GER) and the physiological response to GER in terms of mechanisms of esophageal volume clearance. Furthermore this capability allows assessment of factors that may alter patterns of GER, such as positioning and gastric emptying rate. The aim of our study was to explore the interrelationships between GER, the rate of gastric emptying and body position.
Methods: 10 preterm infants (4 M: 6 F) ranging in weight from 2210–3180g were studied at a post menstrual age of 35–37weeks. Combined manometry and multi-channel intraluminal impedance (MII) was performed using a novel lower esophageal sphincter (LES) sleeve assembly (OD 2.5mm) incorporating 9cm array of 6 impedance rings. After placement of the assembly infants were gavage fed with EBM via an assembly infusion port and then esophageal manometry and MII was recorded for 4hrs post prandially. Liquid and gas GER was identified using standard MII criteria and the esophageal motor mechanism(s) of GER triggering characterised. Gastric emptying rate was determined with a 13C-Na octanoate breath test. The first five infants enrolled were studied in the right lateral position and the next five infants enrolled studied in the left lateral position.
Results: Eighty nine GER episodes were recorded consisting of 74% liquid, 14% gas and 12% mixed. TLESR was the predominant mechanism of reflux, triggering 83% of all GER episodes. Infants studied in the right vs left lateral position respectively had significantly more TLESRs (median [IQR] 13[12–14] vs 2[1–6], p<0.01) and GER (median [IQR] 14[10–14] vs 2[2–8], p<0.05), but paradoxically shorter gastric half emptying time (mean [SEM] 35min vs 75min, p<0.005) when compared with infants studied in the left lateral position.
Conclusion: Right side positioning is associated with increased triggering of TLESR and GER despite paradoxically accelerating gastric emptying. These data suggest that gastric emptying rate alone may have very little influence on the mechanisms that regulate GER triggering.