title: Wireless oesophageal pH monitoring: feasibility, safety and normal values in healthy subjects.
abstract: OBJECTIVE
  A new wireless technique for oesophageal pH monitoring has recently been introduced (Bravo). To implement this technique in clinical practice, values of normal oesophageal acid exposure need to be defined in a large age- and gender-matched healthy population. The aims of this study were to investigate the feasibility and safety of the wireless technique and to establish normal values for oesophageal acid exposure.
  
  
  METHODS
  Fifty-seven asymptomatic subjects underwent upper gastrointestinal endoscopy with transoral placement of a radio-transmitting capsule 6 cm above the squamocolumnar junction. Oesophageal acid exposure was monitored via a portable receiver during 48 h.
  
  
  RESULTS
  Seven men were excluded from the study: capsule dysfunction in 1 and oesophagitis in 6. Fifty subjects (25 M, 25 F, median age 42 years) were included in the study. The radio-transmitting capsule was successfully attached to the oesophageal mucosa in all cases and there were no complications. During pH monitoring 2 capsules were prematurely detached after 32 and 36 h, respectively. The median percentage time with oesophageal pH of less than 4 was 0.7% on day 1 and 1.0% on day 2 (p = 0.033) and the 95th percentile for the 48-h recordings was 4.4%.
  
  
  CONCLUSIONS
  Ambulatory pH monitoring using the Bravo system is feasible and appears to be safe. This is the first study to establish normal values for oesophageal acid exposure in a large age- and gender-matched healthy population and offers a basis for the use of the wireless technique in clinical practice.
authors.affiliation: Department of Surgery, Lund University Hospital, Sweden. jorgen.wenner@kir.lu.se
authors.forename: Jörgen
authors.initials: J
authors.lastname: Wenner
authors.forename: Folke
authors.initials: F
authors.lastname: Johnsson
authors.forename: Jan
authors.initials: J
authors.lastname: Johansson
authors.forename: Stefan
authors.initials: S
authors.lastname: Oberg
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004945:Esophagoscopy / Q000379:methods*; D004947:Esophagus / Q000502:physiology*; D005240:Feasibility Studies; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D012016:Reference Values; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors