title: Intrasubject variability of gastric emptying in the critically ill using a stable isotope breath test.
abstract: OBJECTIVE
  Isotope breath tests are increasingly used to evaluate the effects of prokinetic drugs on gastric emptying. The aim was to assess intrasubject variability in gastric emptying, when using an isotope breath test in the critically ill.
  
  
  METHODS
  A retrospective analysis of data was undertaken in 12 patients who had gastric emptying measurements on consecutive days using a (13)C-octanoic acid breath test. The gastric emptying coefficient--GEC (a global index for the gastric emptying rate), and the t(50) (calculated time for 50% of meal to empty) were calculated, together with the coefficient of variability for these parameters. Data are mean (SD).
  
  
  RESULTS
  Neither GEC (day 1: 3.3 (0.8) vs. day 2: 3.1 (0.6); P = 0.31) nor t(50) (day 1: 127 (43) min vs. day 2: 141 (48) min; P = 0.46) were significantly different between the two days. Intrasubject variability was less for GEC (15.6%) than for t(50) (31.8%).
  
  
  CONCLUSIONS
  There is only modest intrasubject variability in GEC measurements using the (13)C-octanoic acid breath test in critically ill patients. As such, it may be an acceptable measurement tool to assess the effects of prokinetic drugs in this group.
authors.affiliation: Intensive Care Unit, Royal Adelaide Hospital, Adelaide, Australia. adam.deane@adelaide.edu.au
authors.forename: Adam M
authors.initials: AM
authors.lastname: Deane
authors.forename: Antony V
authors.initials: AV
authors.lastname: Zaknic
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Summers
authors.forename: Marianne J
authors.initials: MJ
authors.lastname: Chapman
authors.forename: Kylie
authors.initials: K
authors.lastname: Lange
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ritz
authors.forename: Geoff
authors.initials: G
authors.lastname: Davidson
authors.forename: Michael
authors.initials: M
authors.lastname: Horowitz
authors.forename: Robert J L
authors.initials: RJ
authors.lastname: Fraser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001944:Breath Tests; D002210:Caprylates / Q000032:analysis*; D002247:Carbon Isotopes / Q000032:analysis; D015331:Cohort Studies; D016638:Critical Illness; D004750:Enteral Nutrition; D005260:Female; D005746:Gastric Emptying; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D002210:Caprylates; D002247:Carbon Isotopes