Comparison of nuclear scintigraphy and acetaminophen absorption as a means of studying gastric emptying in horses.
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 administered acetaminophen.


METHODS
6 mature horses.


METHODS
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
Tmax and Ka are valuable variables in the assessment of liquid-phase 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.
Lohmann
K L
KL
Department of Large Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station 77843, USA.
Roussel
A J
AJ
Cohen
N D
ND
Boothe
D M
DM
Rakestraw
P C
PC
Walker
M A
MA
D000082:Acetaminophen / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D019540:Area Under Curve; D004386:Duodenum / Q000378:metabolism; D005260:Female; D016231:Fluorescence Polarization Immunoassay / Q000662:veterinary; D015902:Gamma Cameras / Q000662:veterinary; D005746:Gastric Emptying / Q000502:physiology*; D006207:Half-Life; D006734:Horse Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006736:Horses; D007091:Image Processing, Computer-Assisted; D007408:Intestinal Absorption; D008297:Male; D011877:Radionuclide Imaging; D018709:Statistics, Nonparametric; D013272:Stomach Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000662:veterinary*; D016284:Technetium Tc 99m Pentetate / Q000008:administration & dosage
D018712:Analgesics, Non-Narcotic; D000082:Acetaminophen; D016284:Technetium Tc 99m Pentetate