Background and objective: The aim of this preliminary study performed on volunteers was to assess whether a standardized ultrasonographic measurement of the gastric antral cross-sectional area in a single section of the stomach could discriminate between gastric contents after 12 h fasting (fasting stomach) and gastric contents 2 h after ingestion of nonclear liquids or a solid meal.
Methods: In this crossover study, ultrasonographic measurements of the antral area were performed in the morning in healthy volunteers in three situations in randomized order: after 12 h fasting, 2 h after a solid meal of 300 kcal and 2 h after ingestion of 200 ml of nonclear liquids. These measurements were performed by a physician blinded to the volunteers' status, according to a standardized method, using the abdominal aorta and the left lobe of the liver as internal landmarks. Antral areas were compared among the three sessions, and performance of the test was assessed by plotting receiver operating characteristic curves and calculating the area under the receiver operating characteristic curves for the diagnosis of fasting gastric contents.
Results: Twenty-two volunteers were included, and 65 measures were performed. Antral area was significantly smaller in fasting than in postprandial sessions. The receiver operating characteristic curves showed an excellent performance of ultrasonographic measurement of antral area for discriminating gastric contents in fasting session from gastric contents in nonfasting sessions.
Conclusion: Results of this preliminary study should be corroborated in further trials. However, one can suppose that ultrasonographic measurement of the antral cross-section area could be of interest for the diagnosis of preoperative gastric vacuity.