[Gastric emptying of different liquid test meals measured by ultrasonography]

The rate of gastric emptying of different liquid solutions was measured in 80 voluntary normal young male subjects (mean age 19.9 +/- 1.6 years) by direct real-time ultrasonic imaging. Multiple US scans were repeated at regular intervals (15-30 minutes) until complete gastric emptying was established, after ingestion of 500 cc of 8 different liquid test meals: isotonic saline, 50% glucose, 5% glucose, 40 g of proteins, 20 g of protein, 40 g of fat, 20 g of fat and mixed (carbohydrates, proteins and fat). Eight groups of ten subjects were studied, each one with a different test meal. Three types of gastric emptying were identified: slow (177 +/- 12 minutes) in subjects receiving 50% glucose, 40 and 20 grs of proteins and mixed test meals; intermediate (83 +/- 9 minutes) with 5% glucose, 40 and 20 g of fat; rapid (40 +/- 6 minutes) with isotonic saline. The mixed diet had the slowest emptying time (210 +/- 6 min). Our results are in accordance with published data regarding gastric motor physiology and demonstrates the usefulness of ultrasound in the study of gastric emptying of fluids.