title: Esophageal Acid Clearance During Random Swallowing Is Faster in Patients with Barrett's Esophagus Than in Healthy Controls.
abstract: OBJECTIVE
  Impaired esophageal acid clearance may be a contributing factor in the pathogenesis of Barrett's esophagus. However, few studies have measured acid clearance as such in these patients. In this explorative, cross-sectional study, we aimed to compare esophageal acid clearance and swallowing rate in patients with Barrett's esophagus to that in healthy controls.
  
  
  METHODS
  A total of 26 patients with histology-confirmed Barrett's esophagus and 12 healthy controls underwent (1) upper endoscopy, (2) an acid clearance test using a pH-impedance probe under controlled conditions including controlled and random swallowing, and (3) an ambulatory pH-impedance measurement.
  
  
  RESULTS
  Compared with controls and when swallowing randomly, patients cleared acid 46% faster (P= 0.008). Furthermore, patients swallowed 60% more frequently (mean swallows/minute: 1.90 ± 0.74 vs 1.19 ± 0.58;P= 0.005), and acid clearance time decreased with greater random swallowing rate (P< 0.001). Swallowing rate increased with lower distal esophageal baseline impedance (P= 0.014). Ambulatory acid exposure was greater in patients (P= 0.033), but clearance times assessed from the ambulatory pH-measurement and acid clearance test were not correlated (allP> 0.3).
  
  
  CONCLUSIONS
  More frequent swallowing and thus faster acid clearance in Barrett's esophagus may constitute a protective reflex due to impaired mucosal integrity and possibly acid hypersensitivity. Despite these reinforced mechanisms, acid clearance ability seems to be overthrown by repeated, retrograde acid reflux, thus resulting in increased esophageal acid exposure and consequently mucosal changes.
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.|Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.|Department of Medicine, Vendsyssel Hospital, Hjørring, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Lottrup
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.|Department of Medicine, Vendsyssel Hospital, Hjørring, Denmark.
authors.forename: Anne L
authors.initials: AL
authors.lastname: Krarup
authors.affiliation: GIOME, Department of Surgery, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, Hong Kong SAR.
authors.forename: Hans
authors.initials: H
authors.lastname: Gregersen
authors.affiliation: Department of Surgery, Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Per
authors.initials: P
authors.lastname: Ejstrud
authors.affiliation: Mech-Sense, Department of Gastroenterology and Hepatology, Aalborg University Hospital, Aalborg, Denmark.|Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.|Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: Asbjørn M
authors.initials: AM
authors.lastname: Drewes
keywords: Acid clearance; Barrett esophagus; Deglutition; Esophageal pH monitoring; Gastroesophageal reflux