Objective—To evaluate the correlation between halftime
of liquid-phase gastric emptying (T50), determined
with nuclear scintigraphy using technetium
Tc 99m pentetate, and absorption variables of orally
Animals—6 mature horses.
Procedure—Technetium Tc 99m pentetate (10 mCi)
and acetaminophen (20 mg/kg of body weight) were
administered simultaneously in 200 ml of water. Serial
left and right lateral images of the stomach region
were obtained with a gamma camera, and T50 determined
separately for counts obtained from the left
side, the right side and the geometric mean. Power
exponential curves were used for estimation of T50
and modified R2 values for estimation of goodness of
fit of the data. Serial serum samples were taken, and
acetaminophen concentration was determined, using
fluorescence polarization immunoassay. Maximum
serum concentration (Cmax), time to reach maximum
serum concentration (Tmax), area under the curve for
240 minutes and the absorption constant (Ka) were
determined, using a parameter estimation program.
Correlations were calculated, using the Spearman
rank correlation coefficient.
Results—Correlations between T50 and Tmax and
between T50 and Ka were significant.
Conclusions and Clinical Relevance—Tmax and Ka
are valuable variables in the assessment of liquidphase
gastric emptying using acetaminophen absorption.
Acetaminophen absorption may be a valuable
alternative to nuclear scintigraphy in the determination
of gastric emptying rates in equine patients with
normally functioning small intestine. (Am J Vet Res