Mechanism of gastroesophageal reflux in premature infants with chronic lung disease

Background/Purpose: The aim of this study was to characterize the motor eve nts responsible for gastroesophageal reflux (GER) and esophageal acid clear ance in a cohort of preterm infants with chronic lung disease (CLD). Methods: Esophageal motility was recorded for 2 to 3 hours postprandially i n 14 preterm infants with mild-moderate or moderate-severe CLD at 33 to 39 weeks postmenstrual age using a sleeve-side hole micromanometric assembly i nto which a pH probe had been installed. Results: Twenty-six acid GER episodes were recorded by pH probe. Of these, 22 (85%) were associated with transient lower esophageal sphincter (LES) re laxation. Transient LES relaxations were significantly longer in duration t han single swallows (13.7 seconds v 4.6 seconds, P < .001) and had lower na dir pressures (1.1 mm Hg v 2.5 mm Hg, P < .001). During periods of esophage al acidification (pH below 4), peristaltic esophageal body pressure wave se quences cleared acid refluxate more effectively than nonperistaltic pressur e wave sequences. Conclusions: In preterm infants with CLD, transient LES relaxations are the predominant mechanism underlying GER, and esophageal clearance mechanisms are fully functional, which is similar to that seen in healthy preterm infa nts. J Pediatr Surg 34:1795-1798. Copyright (C) 1999 by W.B. Saunders Compa ny.