Manually calculated oesophageal bolus clearance time increases in parallel with reflux severity at impedance-pH monitoring

Nicola de Bortoli, Irene Martinucci, Edoardo V. Savarino, Marzio Frazzoni, Radu Tutuian, Salvatore Tolone, Paolo Piaggi, Manuele Furnari, Salvatore Russo, Lorenzo Bertani, Lorenzo Macchia, Vincenzo Savarino, Santino Marchi

Research output: Contribution to journalArticlepeer-review


Background: Oesophageal clearance has been scarcely studied. Aims: 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+ (42.6 s), pH+/impedance- (27.1 s), pH-/impedance+ (17.8 s) to pH-/impedance- (10.8 s). 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 14.8 s 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.

Original languageEnglish
Pages (from-to)1027-1032
Number of pages6
JournalDigestive and Liver Disease
Issue number12
Publication statusPublished - Dec 1 2015


  • Bolus clearance time
  • GERD
  • PH-impedance monitoring
  • PSPW index

ASJC Scopus subject areas

  • Medicine(all)
  • Hepatology
  • Gastroenterology


Dive into the research topics of 'Manually calculated oesophageal bolus clearance time increases in parallel with reflux severity at impedance-pH monitoring'. Together they form a unique fingerprint.

Cite this