title: Esophageal impedance baselines in infants before and after placebo and proton pump inhibitor therapy.
abstract: BACKGROUND
  Esophageal impedance monitoring records changes in conductivity. During esophageal rest, impedance baseline values may represent mucosal integrity. The aim of this study was to assess the influence of acid suppression on impedance baselines in a placebo-controlled setting.
  
  
  METHODS
  Impedance recordings from 40 infants (0-6 months) enrolled in randomized placebo-controlled trials of proton pump inhibitor (PPI) were retrospectively analyzed. Infants underwent 24 h pH-impedance monitoring prior to and after 2 weeks of double blind therapy with placebo or a PPI. Typical clinical signs of gastro-esophageal reflux (GER) were recorded and I-GERQ-R questionnaire was completed.
  
  
  RESULTS
  Median (IQR) impedance baseline increased on PPI treatment (from 1217 (826-1514) to 1903 (1560-2194) Ω, P < 0.001) but not with placebo (from 1445 (1033-1791) to 1650 (1292-1983) Ω, P = 0.13). Baselines before treatment inversely correlate with the number of GER, acid GER, weakly acid GER, acid exposure, and symptoms. The change in baseline on treatment inversely correlates with acid exposure and acid GER. Patients with initial low baselines have no improved symptomatic response to treatment.
  
  
  CONCLUSIONS
  Impedance baselines are influenced by GER and increase significantly more with PPI therapy than with placebo. Clinical impact of this observation remains undefined as targeting therapy at infants with low baselines does not improve symptomatic response to treatment.
authors.affiliation: Department of Pediatric Gastroenterology and Nutrition, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands. c.m.loots@amc.nl
authors.forename: C M
authors.initials: CM
authors.lastname: Loots
authors.forename: R
authors.initials: R
authors.lastname: Wijnakker
authors.forename: M P
authors.initials: MP
authors.lastname: van Wijk
authors.forename: G
authors.initials: G
authors.lastname: Davidson
authors.forename: M A
authors.initials: MA
authors.lastname: Benninga
authors.forename: T I
authors.initials: TI
authors.lastname: Omari
mesh_terms: D004311:Double-Blind Method; D017097:Electric Impedance; D050782:Esophageal pH Monitoring; D004947:Esophagus / Q000187:drug effects*; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000188:drug therapy; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D054328:Proton Pump Inhibitors / Q000009:adverse effects*; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies
chemical_list: D054328:Proton Pump Inhibitors