Paradoxical impact of body positioning on gastroesophageal reflux and gastric emptying in the premature neonate

Objectives To combine manometry and impedance to characterize the mechanisms of gastroesophageal reflux (GER) and to explore their relation to the rate of gastric emptying (GE) and body position. Study design Ten healthy preterm infants (35 to 37 weeks' postmenstrual age) were studied with the use of a micromanometric/impedance assembly. Episodes of GER were identified by impedance, and the mechanism(s) of GER triggering and GER clearance were characterized. GE was determined with a C13Na-octanoate breath test. Results Gastroesophageal reflux episodes (n = 89) were recorded, consisting of 74% liquid, 14% gas, and 12% mixed. Transient lower esophageal sphincter relaxation (TLESR) was the predominant mechanism of reflux, triggering 83% of GER. Of 92 TLESRs recorded, 27% were not associated with reflux. Infants studied in the right lateral position had significantly (P <.01) more GER, a higher proportion of liquid GER (P <.05). and faster GE (P <.005) when compared with infants studied in the left lateral position. Conclusions In healthy preterm infants, GER is predominantly liquid in nature. Right-side positioning is associated with increased triggering of TLESR and GER despite accelerating GE.