Validation of the 13C-octanoic acid breath test for measurement of equine gastric emptying rate of solids using radioscintigraphy.
BACKGROUND
Disordered gastric motility may be a significant factor in the pathogenesis of many equine conditions. Although tests for liquid phase emptying rate have been validated in the horse, there are no effective tests for solid phase emptying measurement that can be performed routinely in the field.


OBJECTIVE
The objective of this study was the assessment of a novel stable isotope technique, the 13C-octane acid breath test (13C-OABT), for the measurement of gastric emptying of solid ingesta, by direct comparison with the optimum method of gastric scintigraphy.


METHODS
To facilitate dual measurement of gastric emptying, a test meal was used containing baked egg yolk labelled with both 13C-octanoic acid and 99mtechnetium sulphur colloid. Simultaneous, serial lateral gastric scintigraphs and expiratory breath samples were obtained in 12 healthy horses after voluntary ingestion of the test meal. Analysis of breath 13CO2:12CO2 ratio was performed by continuous flow isotope ratio mass spectrometry. Power regression was used to determine the gastric emptying coefficient, the gastric half-emptying time (t 1/2) and duration of the lag phase (tlag).


RESULTS
Significant correlations (P < 0.001) were found between the 2 techniques for measurement of both t 1/2 and tlag. In addition, scintigraphic left t 1/2 was correlated significantly to breath test gastric emptying coefficient (P < 0.001).


CONCLUSIONS
It was concluded that the 13C-octanoic acid breath test is a reliable diagnostic procedure to measure gastric emptying rate of solids in the horse.


CONCLUSIONS
Being safe, noninvasive and easy to perform, this test has potential value as both sensitive diagnostic modality and humane research tool for motility studies.
Sutton
D G M
DG
Institute of Comparative Medicine, University of Glasgow Veterinary School, Bearsden Road, Glasgow G61 1QH, UK.
Bahr
A
A
Preston
T
T
Christley
R M
RM
Love
S
S
Roussel
A J
AJ
D000818:Animals; D001944:Breath Tests / Q000379:methods*; D002210:Caprylates / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D005260:Female; D005746:Gastric Emptying / Q000502:physiology; D006734:Horse Diseases / Q000175:diagnosis; D006736:Horses / Q000502:physiology*; D008297:Male; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D013270:Stomach / Q000000981:diagnostic imaging* / Q000502:physiology; D013671:Technetium Tc 99m Sulfur Colloid; D013997:Time Factors
D002210:Caprylates; D002247:Carbon Isotopes; D002245:Carbon Dioxide; D013671:Technetium Tc 99m Sulfur Colloid; C031492:octanoic acid