title: Reproducibility of axial force and manometric recordings in the oesophagus during wet and dry swallows.
abstract: BACKGROUND
  Manometry is the golden standard to diagnose oesophageal motility disorders but it gives an indirect picture of the peristalsis by measuring radial force only. A novel probe design using electrical impedance recordings enabled axial force and manometry to be recorded simultaneously. Using this method the aims were to study the amplitude and duration of peristaltic contractions, to test the correlation between axial force and manometry, and the reproducibility of the method.
  
  
  METHODS
  Ten healthy men were included twice. The probe was positioned 5 cm proximal to the lower oesophageal sphincter after which five dry swallows and five wet swallows were done. This was repeated with 0, 2, 4 and 6 mL of water in a bag mounted distal to the axial force recording site.
  
  
  RESULTS
  Duration and amplitude of contractions were measured by axial force and manometry. Both increased with the bag volume (P < 0.05), with force measurements having approximately twice the dynamic range than manometry (P < 0.05). Contraction duration and amplitude showed good reproducibility for both axial force and manometry (interclass correlation coefficients >0.6). The best association between axial force and manometry was found during wet swallows with an empty bag (r = 0.72, P < 0.001), otherwise these measurements were not associated.
  
  
  CONCLUSIONS
  The system provided a more complete description of primary oesophageal peristalsis. Axial force and manometry were both reproducible but force measurements had increased dynamic range. As manometry and axial force generally are not associated, they each provide different information, and in combination they may be useful to better characterize oesophageal motor function.
authors.affiliation: Mech-Sense, Department of Gastroenterology & Science and Innovation Center, Aalborg Hospital, Aalborg, Denmark.
authors.forename: F H
authors.initials: FH
authors.lastname: Gravesen
authors.forename: H
authors.initials: H
authors.lastname: Gregersen
authors.forename: L
authors.initials: L
authors.lastname: Arendt-Nielsen
authors.forename: A M
authors.initials: AM
authors.lastname: Drewes
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D003679:Deglutition / Q000502:physiology*; D004867:Equipment Design; D004947:Esophagus / Q000502:physiology*; D006801:Humans; D008297:Male; D008365:Manometry / Q000295:instrumentation* / Q000379:methods; D008875:Middle Aged; D010528:Peristalsis / Q000502:physiology*