A Review of Methods for Assessment of the Rate of Gastric Emptying in the Dog and Cat: 1898–2002

Abstract

Gastric emptying is the process by which food is delivered to the small intestine at a rate and in a form that optimizes intestinal absorption of nutrients. The rate of gastric emptying is subject to alteration by physiological, pharmacological, and pathological conditions. Gastric emptying of solids is of greater clinical significance because disordered gastric emptying rarely is detectable in the liquid phase. Imaging techniques have the disadvantage of requiring restraint of the animal and access to expensive equipment. Radiographic methods require administration of test meals that are not similar to food. Scintigraphy is the gold standard method for assessment of gastric emptying but requires administration of a radioisotope. Magnetic resonance imaging has not yet been applied for assessment of gastric emptying in small animals. Ultrasonography is a potentially useful, but subjective, method for assessment of gastric emptying in dogs. Gastric tracer methods require insertion of gastric or intestinal cannulae and are rarely applied outside of the research laboratory. The paracetamol absorption test has been applied for assessment of liquid phase gastric emptying in the dog, but requires IV cannulation. The gastric emptying breath test is a noninvasive method for assessment of gastric emptying that has been applied in dogs and cats. This method can be carried out away from the veterinary hospital, but the effects of physiological and pathological abnormalities on the test are not known. Advances in technology will facilitate the development of reliable methods for assessment of gastric emptying in small animals.Key words: Barium-impregnated polyethylene spheres; Breath test; Radiography; Scintigraphy; Ultrasonography.T he important role of the stomach in the digestion of food has been recognized for many centuries. The term ''pylorus'' dates from before the 5th century and is derived from the Greek, meaning ''keeper of the gate,'' an indication that early physicians had some understanding of the physiological function of gastric emptying. The rate of gastric emptying was assessed noninvasively for the 1st time in 1898, when the Harvard physiologist, W.B. Cannon, used X-rays to trace the outline of a radiopaque meal passing through the stomach of a cat (Fig 1).1 Over the next 6 years, Cannon used this method to characterize the functional significance of fundic and antral contractions and demonstrated the effect of emotion and food on the rate of gastric emptying.1,2 Together, these studies formed the cornerstones of the study of gastric motility, and Cannon's findings continue to influence our understanding of gastric emptying to this day. Indeed, over 100 years later, the radiographic tracing of gastric emptying remains the most commonly applied method for assessment of gastric motility in veterinary medicine. 3More recently, the dog has been used as an animal model for the study of human gastric emptying in many physiological and pharmacological studies, and gastric emptying is now more clearly understood in...

Toxicology of Avermectins and Milbemycins (Macrocylic Lactones) and the Role of P-Glycoprotein in Dogs and Cats

“…Rather, several factors must be considered. Liquid or paste formulations of MLs are anticipated to empty from the stomach rather quickly compared to solid formulations, 66 although mixing with recently ingested food may slow the emptying of nonsolid formulations. 67 Also, inducing emesis will not only delay the administration of activated charcoal, which is likely to be of greater benefit in reducing absorption of MLs than emesis, but will also make it more likely that subsequently administered activated charcoal will be vomited.…”

Assessment of the Variation Associated with Repeated Measurement of Gastrointestinal Transit Times and Assessment of the Effect of Oral Ranitidine on Gastrointestinal Transit Times Using a Wireless Motility Capsule System in Dogs

“…Although several techniques for assessing canine gastric emptying time (GET) have been reported, each of these has limitations [1]. Nuclear scintigraphy is currently considered to be the gold standard method for assessing GET in both humans [2] and dogs [1].…”

“…Nuclear scintigraphy is currently considered to be the gold standard method for assessing GET in both humans [2] and dogs [1]. The radiopharmaceutical agents used for nuclear scintigraphy mix readily with the test meal, allowing this technique to provide a representative assessment of solid-phase gastric emptying.…”

Phenylalanine flux and gastric emptying are not affected by replacement of casein with whey protein in the diet of adult cats consuming frequent small meals

“…Estimation of gastric emptying from appearance of an oral [ 13 C]Phe dose in plasma is analogous to the acetaminophen absorption test for evaluating liquid-phase gastric emptying [ 24 ]. Acetaminophen is poorly absorbed from the stomach and rapidly absorbed in the proximal duodenum so an oral dose appears in plasma according to the rate of delivery from stomach to small intestine [ 25 ].…”

“…Gastric emptying measurements are usually performed after a test meal representing 50 to 100% of the daily nutrient intake while we offered only 1/24 of the daily intake with the gastric emptying tracer. The large meal size in gastric emptying studies is used as part of a standardized protocol to allow clinical detection of pathological or pharmacological abnormalities in individuals [ 24 ]. Our objective, on the other hand, was to compare amino acid supply from casein- and whey-based diets and, in order to measure amino acid flux, we maintained a non-isotopic steady-state of amino acid concentrations by feeding frequent small meals throughout the day.…”