title: Manually calculated oesophageal bolus clearance time increases in parallel with reflux severity at impedance-pH monitoring.
abstract: BACKGROUND
  Oesophageal clearance has been scarcely studied.
  
  
  OBJECTIVE
  Oesophageal clearance in endoscopy-negative heartburn was assessed to detect differences in bolus clearance time among patients sub-grouped according to impedance-pH findings.
  
  
  METHODS
  In 118 consecutive endoscopy-negative heartburn patients impedance-pH monitoring was performed off-therapy. Acid exposure time, number of refluxes, baseline impedance, post-reflux swallow-induced peristaltic wave index and both automated and manual bolus clearance time were calculated. Patients were sub-grouped into pH/impedance positive (abnormal acid exposure and/or number of refluxes) and pH/impedance negative (normal acid exposure and number of refluxes), the former further subdivided on the basis of abnormal/normal acid exposure time (pH+/-) and abnormal/normal number of refluxes (impedance+/-).
  
  
  RESULTS
  Poor correlation (r=0.35) between automated and manual bolus clearance time was found. Manual bolus clearance time progressively decreased from pH+/impedance+ (42.6s), pH+/impedance- (27.1s), pH-/impedance+ (17.8s) to pH-/impedance- (10.8s). There was an inverse correlation between manual bolus clearance time and both baseline impedance and post-reflux swallow-induced peristaltic wave index, and a direct correlation between manual bolus clearance and acid exposure time. A manual bolus clearance time value of 14.8s had an accuracy of 93% to differentiate pH/impedance positive from pH/impedance negative patients.
  
  
  CONCLUSIONS
  When manually measured, bolus clearance time reflects reflux severity, confirming the pathophysiological relevance of oesophageal clearance in reflux disease.
authors.affiliation: Division of Gastroenterology, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy. Electronic address: nick.debortoli@gmail.com.
authors.forename: Nicola
authors.initials: N
authors.lastname: de Bortoli
authors.affiliation: Division of Gastroenterology, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
authors.forename: Irene
authors.initials: I
authors.lastname: Martinucci
authors.affiliation: Division of Gastroenterology, Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy.
authors.forename: Edoardo V
authors.initials: EV
authors.lastname: Savarino
authors.affiliation: Digestive Pathophysiology Unit, Baggiovara Hospital, Modena, Italy.
authors.forename: Marzio
authors.initials: M
authors.lastname: Frazzoni
authors.affiliation: Gastroenterology Unit, University Hospital of Bern, Switzerland.
authors.forename: Radu
authors.initials: R
authors.lastname: Tutuian
authors.affiliation: Division of Surgery, Department of Surgery, Second University of Naples, Naples, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Tolone
authors.affiliation: Obesity Research Center, Department of Clinical and Experimental Medicine, University of Pisa, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Piaggi
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Genoa, Genoa, Italy.
authors.forename: Manuele
authors.initials: M
authors.lastname: Furnari
authors.affiliation: Division of Gastroenterology, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Russo
authors.affiliation: Division of Gastroenterology, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Bertani
authors.affiliation: Gastroenterology Unit, University Hospital of Bern, Switzerland.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Macchia
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, University of Genoa, Genoa, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Savarino
authors.affiliation: Division of Gastroenterology, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
authors.forename: Santino
authors.initials: S
authors.lastname: Marchi
mesh_terms: D000328:Adult; D000368:Aged; D003679:Deglutition; D017097:Electric Impedance; D004724:Endoscopy; D050782:Esophageal pH Monitoring; D004947:Esophagus / Q000503:physiopathology*; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006356:Heartburn / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
keywords: Bolus clearance time; GERD; PSPW index; pH-impedance monitoring