title: Biliary reflux and non-acid reflux are two distinct phenomena: a comparison between 24-hour multichannel intraesophageal impedance and bilirubin monitoring.
abstract: OBJECTIVE
  Duodenogastroesophageal reflux (DGER) can greatly increase microscopic and macroscopic esophageal mucosal damage caused by acid. The aim of this study was simultaneously to assess the chemical composition of DGER by detecting bilirubin in the refluxate by means of Bilitec and describe its pH and physical properties by impedance monitoring, in order to prove that non-acid reflux and biliary reflux are two distinct phenomena.
  
  
  METHODS
  Twenty patients with gastroesophageal reflux disease (GERD) with symptoms refractory to conventional proton-pump inhibitor (PPI) therapy or with atypical GERD symptoms were included in the study. All patients underwent upper gastrointestinal endoscopy and simultaneous Bilitec and intraeosophageal impedance (IIM) and pH monitoring. In the majority of patients (16/20), the tests were performed while assuming a standard PPI dose.
  
  
  RESULTS
  Pathological bilirubin exposure, as defined by intraesophageal bilirubin absorbance above 0.14 for more than 3.9% of the time, was present in 9 cases, 6 of them with normal values of non-acid reflux, as detected by IIM. A pathological non-acid reflux, as defined by an IIM showing a percentage time with non-acid reflux greater than 1.4%, was observed in 5 patients, 2 of whom had no pathological biliary reflux, as detected by Bilitec. No correlation was found between the two indices, as expressed by an r-value of -0.12 (p>0.05).
  
  
  CONCLUSIONS
  Our study confirms that biliary reflux and non-acid reflux as detected by Bilitec and by IIM, respectively, are two distinct phenomena that require different techniques in order to be assessed in humans.
authors: Division of Gastroenterology, L. Sacco University Hospital, Milan, Italy. cn.fapac@tin.it
authors: Fabio
authors: F
authors: Pace
authors: Ornella
authors: O
authors: Sangaletti
authors: Stefano
authors: S
authors: Pallotta
authors: Paola
authors: P
authors: Molteni
authors: Gabriele Bianchi
authors: GB
authors: Porro
mesh_terms: D000328:Adult; D000368:Aged; D001655:Bile Reflux / Q000175:diagnosis / Q000378:metabolism; D001663:Bilirubin / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis; D003937:Diagnosis, Differential; D004383:Duodenogastric Reflux / Q000175:diagnosis* / Q000378:metabolism; D017097:Electric Impedance; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000379:methods; D011446:Prospective Studies; D013053:Spectrophotometry; D013997:Time Factors
chemical_list: D015415:Biomarkers; D001663:Bilirubin