title: Subcardial 24-h wireless pH monitoring in gastroesophageal reflux disease patients with and without hiatal hernia compared with healthy subjects.
abstract: OBJECTIVE
  After meals, highly acidic gastric juice is present in the subcardial region, the so-called acid pocket. Patients with gastroesophageal reflux disease (GERD) have a higher frequency of acidic reflux. Our aim was to investigate the possible differences in subcardial pH in GERD over 24 h and the role of hiatal hernia (HH), using a wireless capsule.
  
  
  METHODS
  A total of 14 healthy volunteers (4 men, 24-60 years), 10 GERD patients without HH (4 men, 25-68 years), and 11 GERD patients with HH >or=3 cm (2 men, 46-74 years) underwent 24-h wireless pH monitoring 2 cm below the squamocolumnar junction. All patients had increased 24-h acid reflux. A standardized lunch was given to all study subjects.
  
  
  RESULTS
  No capsule detached during the 24-h recording. Median 24-h pH was similar in healthy subjects, and in patients without and with HH, median: 1.4 (interquartile range: 1.2 -1.9), 1.5 (1.3 -1.7), and 1.4 (1.3 -1.7), respectively. Similar results were seen in the supine period. Median pH after the standardized meal was often highly acidic, 2.7 (1.5 - 3.2), 1.9 (1.6 - 2.3), and 2.5 (1.6 - 3.2), respectively. The first minute with a median pH <2 occurred 14 min (4 - 49), 14 min (6 - 25), and 20 min (4 - 43), respectively, P=NS, after the end of the meal. Similar data were observed on pooling all meals together.
  
  
  CONCLUSIONS
  Subcardial pH is confirmed to be highly acidic early after meals, but it is similar over 24 h in healthy subjects and GERD patients independent of the presence of HH.
authors.affiliation: Cattedra di Gastroenterologia, Dipartimento di Scienze Mediche, Università degli Studi of Milan, Milan, Italy.
authors.forename: Ausilia
authors.initials: A
authors.lastname: Grigolon
authors.forename: Paolo
authors.initials: P
authors.lastname: Cantú
authors.forename: Ivana
authors.initials: I
authors.lastname: Bravi
authors.forename: Chiara
authors.initials: C
authors.lastname: Caparello
authors.forename: Roberto
authors.initials: R
authors.lastname: Penagini
mesh_terms: D000328:Adult; D000368:Aged; D053704:Capsule Endoscopy; D016022:Case-Control Studies; D017097:Electric Impedance; D050782:Esophageal pH Monitoring / Q000295:instrumentation*; D005260:Female; D005500:Follow-Up Studies; D005745:Gastric Acidity Determination; D005764:Gastroesophageal Reflux / Q000150:complications / Q000175:diagnosis*; D006551:Hernia, Hiatal / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D019518:Postprandial Period; D012016:Reference Values; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D016683:Supine Position; D013997:Time Factors