title: Mechanism of gastroesophageal reflux in premature infants with chronic lung disease.
abstract: OBJECTIVE
  The aim of this study was to characterize the motor events responsible for gastroesophageal reflux (GER) and esophageal acid clearance in a cohort of preterm infants with chronic lung disease (CLD).
  
  
  METHODS
  Esophageal motility was recorded for 2 to 3 hours postprandially in 14 preterm infants with mild-moderate or moderate-severe CLD at 33 to 39 weeks postmenstrual age using a sleeve-side hole micromanometric assembly into 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) relaxation. Transient LES relaxations were significantly longer in duration than single swallows (13.7 seconds v 4.6 seconds, P < .001) and had lower nadir pressures (1.1 mm Hg v 2.5 mm Hg, P < .001). During periods of esophageal acidification (pH below 4), peristaltic esophageal body pressure wave sequences cleared acid refluxate more effectively than nonperistaltic pressure 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 infants.
authors.affiliation: Department of Biomedical Engineering, Women's and Children's Hospital, North Adelaide, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Omari
authors.forename: C
authors.initials: C
authors.lastname: Barnett
authors.forename: A
authors.initials: A
authors.lastname: Snel
authors.forename: G
authors.initials: G
authors.lastname: Davidson
authors.forename: R
authors.initials: R
authors.lastname: Haslam
authors.forename: M
authors.initials: M
authors.lastname: Bakewell
authors.forename: J
authors.initials: J
authors.lastname: Dent
mesh_terms: D002908:Chronic Disease; D003679:Deglutition / Q000502:physiology; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000503:physiopathology*; D008171:Lung Diseases / Q000503:physiopathology*; D008297:Male; D008365:Manometry; D011312:Pressure