O0117 REPRODUCIBILITY OF THE 13 C OCTANOIC ACID BREATH TEST FOR THE MEASUREMENT OF GASTRIC EMPTYING OF SOLIDS IN CHILDREN

Abstract

Introduction: The “gold standard” for measuring gastric emptying is scintigraphy. The 13 C octanoic acid breath test is an interesting alternative to measure the gastric emptying of solids, as it is non radioactive. The 13 C octanoic acid breath test using mass spectrometry has been validated against scintigraphy in adults (Ghoos, Gastroenterology 1993;104:1640–7) and has a physiological day-to-day variability in adults (mean coefficient of variation: 26.71 % for gastric half emptying time, 44.93 % for gastric lag phase, 10.82 for gastric emptying coefficient )(Ghoos, Gastroenterology 1993;104:1640–7) as well as in premature infants (mean coefficient of variation: 23.9 % for gastric half emptying time, 12.2 % for gastric emptying coefficient) (Barnett, JPGN 1999; 29: 26–30). There are no data in the literature concerning the use of Non Dispersive InfraRed Spectrometry (NDIRS) in the evaluation of gastric emptying of solids with octanoic acid in children. This study was performed to assess the reproducibility of the 13 C octanoic acid breath test for gastric emptying of solids in children using NDIRS. Methods: Gastric emptying for solids was tested in 19 healthy children (6 girls, 13 boys). After an overnight fasting, a solid test meal consisting of a pancake with a caloric content of 230 kcal, and labelled with 50 microliter 13 C octanoic acid, was given. Breath samples were taken before feeding and at 15 minutes interval after feeding for 4 hours. Samples were analyzed using NDIRS (Wagner Analysen Technik, Worpswede, Germany), and 13 C recovery was used to calculate values for gastric half emptying time (t1/2), time of peak 13 C exhalation or gastric lag phase (tlag) and gastric emptying coefficient (GEC). The 13 C octanoic acid breath test was then repeated 2 or more times 2 to 7 days apart (2 patients 4 times, 7 patients 3 times, 10 patients 2 times). Intra-individual variability and reproducibility of the parameters t1/2, tlag and GEC were expressed as coefficient of variation (CV). Results: The median age was 12.83 years (range 6.75 –17.08), the median CV of t1/2 was 12.9 % (range 2.5 – 29.6) for a t1/2 with a range between 89 and 220 minutes, the median CV of tlag was 12.4 % (range 0.8 – 27.8) for a tlag with a range between 61 and 163 minutes, the median CV of GEC was 10.9 % (range 3.4 – 30.2) for a GEC with a range between 1.82 and 4.20. The CV’s of t1/2, tlag and GEC were independent of the values of t1/2, tlag and GEC. Conclusion: The 13 C octanoic acid breath test using NDIRS is an easy and non-radioactive procedure with very good reproducibility for measuring the gastric emptying of solids in children.