title: Bowel preparation affects the amplitude and spatiotemporal organization of colonic propagating sequences.
abstract: BACKGROUND
  Colonic manometry is performed using either colonoscopically assisted catheter placement, after bowel preparation, or nasocolonic intubation of the unprepared bowel. There has been little systematic evaluation of the effects of bowel cleansing upon colonic propagating pressure wave sequences.
  
  
  METHODS
  Eight healthy volunteers underwent nasocolonic placement of a water-perfused silicone catheter which recorded pressures at 16 recording sites each spaced 7.5 cm apart in the unprepared colon for 24 h. These measures were compared with those obtained in another eight healthy volunteers in whom the catheter was placed to the caecum at colonoscopy in the prepared colon.
  
  
  RESULTS
  The colonic motor responses to meals and morning waking, and the normal nocturnal suppression did not differ between the two groups, nor were the overall frequency, regional dependence nor extent of propagating sequences (PS) influenced by bowel preparation. Bowel preparation did result in a significant increase in the frequency of high amplitude PS (22 +/- 7 vs 8 +/- 4 HAPS/24 h; P = 0.003). Additionally, a number of the measures of spatiotemporal organization among consecutive PS (linkage among sequences and predefecatory stereotypical patterning) were significantly altered by bowel preparation.
  
  
  CONCLUSIONS
  The overall frequency of PSs, the colonic responses to physiological stimuli such a meal and morning waking and nocturnal suppression, are not influenced by prior bowel preparation. However, investigators wishing to study HAPS frequency, or the more complex spatiotemporal relationships among consecutive PSs, should control for bowel preparation when making comparisons among study groups.
authors.affiliation: Department of Gastroenterology, The St George Hospital, University of New South Wales, Kogarah, NSW 2217, Australia. p.dinning@unsw.edu.au
authors.forename: P G
authors.initials: PG
authors.lastname: Dinning
authors.forename: N
authors.initials: N
authors.lastname: Zarate
authors.forename: M M
authors.initials: MM
authors.lastname: Szczesniak
authors.forename: S D
authors.initials: SD
authors.lastname: Mohammed
authors.forename: S L
authors.initials: SL
authors.lastname: Preston
authors.forename: P D
authors.initials: PD
authors.lastname: Fairclough
authors.forename: P J
authors.initials: PJ
authors.lastname: Lunniss
authors.forename: I J
authors.initials: IJ
authors.lastname: Cook
authors.forename: S M
authors.initials: SM
authors.lastname: Scott
mesh_terms: D000328:Adult; D002404:Catheterization; D002432:Cecum / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D003106:Colon / Q000502:physiology*; D003113:Colonoscopy; D003627:Data Interpretation, Statistical; D003672:Defecation / Q000502:physiology; D004435:Eating / Q000502:physiology; D005769:Gastrointestinal Motility / Q000502:physiology; D006801:Humans; D008297:Male; D008365:Manometry / Q000379:methods*; D011312:Pressure; D055815:Young Adult