title: Parameters for quantifying bolus retention with high-resolution impedance manometry.
abstract: BACKGROUND
  This study aimed to develop a methodology for quantifying esophageal bolus retention using a high-resolution esophageal impedance topography (EIT) technique.
  
  
  METHODS
  The ability of impedance to quantify bolus retention was validated by comparison with concurrent fluoroscopic imaging (barium bolus) in 10 healthy subjects. High-resolution impedance manometry (HRIM) studies without fluoroscopy were performed in another 15 healthy subjects to define normal values using saline. HRIM data from each subject were analyzed using a MATLAB program customized for calculating the esophageal impedance integral (EII) prior to the contraction wave front as EII1 and after the contraction as EII2, and presented as a ratio of EII2/EII1, which was compared to the percent of barium areas retained in the esophagus on fluoroscopy determined by a blinded reviewer.
  
  
  RESULTS
  In 93% (37/40) of barium swallows, the results from the EIT method were in agreement with fluoroscopy results with one of three patterns: (1) 25 normal bolus transit, (2) eight bolus stasis, and (3) four retrograde escape or reflux. Three swallows (8%) had slight retention identified by EIT, but no retention detected by fluoroscopy. The correlation between percent of bolus retained in the esophagus detected by fluoroscopy and percent of bolus retention (EII2/EII1) after swallows with EIT method was r = 0.96 (p < 0.001) in supine and r = 0.69 (p < 0.001) in upright position.
  
  
  CONCLUSIONS
  The EII ratio (EII2/EII1) is a surrogate for the fraction of retained bolus after a swallow and this metric may be useful in better defining esophageal function.
authors.affiliation: Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Lin
authors.forename: F
authors.initials: F
authors.lastname: Nicodème
authors.forename: C-Y
authors.initials: CY
authors.lastname: Lin
authors.forename: B
authors.initials: B
authors.lastname: Mogni
authors.forename: L
authors.initials: L
authors.lastname: Friesen
authors.forename: P J
authors.initials: PJ
authors.lastname: Kahrilas
authors.forename: J E
authors.initials: JE
authors.lastname: Pandolfino
mesh_terms: D000328:Adult; D003679:Deglutition / Q000502:physiology*; D017097:Electric Impedance; D004947:Esophagus / Q000503:physiopathology*; D005260:Female; D005471:Fluoroscopy; D005764:Gastroesophageal Reflux / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D010528:Peristalsis / Q000502:physiology; D055815:Young Adult
keywords: bolus retention; esophageal emptying; esophagus; fluoroscopy; impedance; manometry
references.citation: Am J Gastroenterol. 2011 Feb;106(2):349-56
references.pmid: 20924368
references.citation: Am J Gastroenterol. 2011 Oct;106(10):1854-6; author reply 1856-7
references.pmid: 21979209
references.citation: Am J Physiol Gastrointest Liver Physiol. 2005 May;288(5):G1000-6
references.pmid: 15826930
references.citation: Am J Gastroenterol. 2009 Nov;104(11):2721-8
references.pmid: 19690527
references.citation: Am J Gastroenterol. 2004 Jun;99(6):1011-9
references.pmid: 15180718
references.citation: Clin Gastroenterol Hepatol. 2003 May;1(3):174-82
references.pmid: 15017488
references.citation: Am J Physiol Gastrointest Liver Physiol. 2001 Mar;280(3):G457-62
references.pmid: 11171628
references.citation: Dis Esophagus. 2012 Sep-Oct;25(7):600-7
references.pmid: 22243520
references.citation: Neurogastroenterol Motil. 2010 Dec;22(12):1292-7, e336-7
references.pmid: 20718946
references.citation: Gut. 2004 Jul;53(7):1024-31
references.pmid: 15194656
references.citation: Neurogastroenterol Motil. 2012 Nov;24(11):e549-56
references.pmid: 22963535
references.citation: Am J Gastroenterol. 1999 Feb;94(2):306-17
references.pmid: 10022621
references.citation: Gut. 2003 Jun;52(6):784-90
references.pmid: 12740331