Background: This prospective observational study aimed to assess the feasibility and performance of the ultrasonographic measurement of antral cross-sectional area (CSA) for the preoperative assessment of gastric contents and volume in adult patients and for the diagnosis of risk stomach (defined by the presence of solid particles and/or gastric fluid volume >0.8 ml/kg). Methods: A preoperative ultrasonographic measurement of the antral CSA was performed for each patient by a physician (L.B.) blinded to the history of the patient. Immediately after tracheal intubation, an 18-French multiorifice Salem tube was inserted and gastric contents were aspirated in five different patient positions; during this time, the patient's epigastrium was massaged and the tube was moved backward and forward in the stomach. The relationship between the antral area and the volume of aspirated gastric contents was analyzed, as was the performance of ultrasonographic measurement of antral area for the diagnosis of risk stomach. Results: The measurement of antral CSA was performed on 180 of 183 patients. A significant positive relationship between antral CSA and aspirated fluid volume was found. The cutoff value of antral CSA of 340 mm(2) for the diagnosis of risk stomach was associated with a sensitivity of 91% and a specificity of 71%. The area under the receiver operating characteristic curve for the diagnosis of risk stomach was 90%. Conclusions: The ultrasonographic measurement of antral CSA could be an important help for the anesthesiologist in minimizing the risk of pulmonary aspiration of gastric contents due to general anesthesia.

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. 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. 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. 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.

Background. This prospective observational study sought to assess the rate of full and empty stomach in elective and emergency patients and to determine the factors associated with full stomach. Methods. Non-premedicated patients were consecutively included between May 2014 and October 2014. Ultrasound examination of the gastric antrum was performed by an operator blinded to the history of the patient. It included measurement of the antral cross-sectional area, performed in the supine position with the head of the bed elevated to 45°, and qualitative assessment of the gastric antrum, performed in both semirecumbent and right lateral decubitus positions. Full stomach was defined by the appearance of any gastric content in both positions (Grade 2). Empty stomach was defined either by empty antrum in both positions (Grade 0) or by empty antrum in the semirecumbent position only (Grade 1) with measured antral area 340 mm² defined intermediate stomach. Logistic regression analyses were performed for the identification of factors associated with full stomach. Results. Four hundred and forty patients were analysed. The prevalence of full stomach was 5% (95% confidence interval: 2–9) in elective patients and 56% (95% confidence interval: 50–62) in emergency patients (P<0.0001). Obesity, diabetes mellitus, emergency surgery, and preoperative consumption of opiates were independent factors predictive of full stomach. Conclusions. The results suggest that preoperative ultrasound assessment of gastric content should be performed in all emergency patients, and in elective patients with identified predictive factors for full stomach.

Summary: Background: Though pulmonary aspiration of gastric contents occurs mainly in the setting of emergency surgery, it may also occur in children scheduled for elective surgery without any obvious clinical risk factor. Increased gastric content volume is one the predisposing factors for pulmonary aspiration that could affect such children and may be identified using ultrasound examination of the gastric antrum.Aims: We aimed to assess the prevalence of “at‐risk stomach” defined by ultrasound visualization of any solid content in the antrum and/or by calculated gastric fluid volume > 1.25 mL/kg, in children scheduled for elective surgery.Methods: Children scheduled for elective surgery were consecutively included into this prospective cohort study. Preoperative ultrasound examination of the antrum was performed in both the supine and the right lateral decubitus positions. Gastric fluid content was assessed using a 0‐2 qualitative grading scale. The antral cross‐sectional area was also measured in both the supine and the right lateral decubitus positions, allowing the calculation of the gastric fluid volume according to a formula previously described.Results: We analyzed 200 elective children. Median duration of fasting was 4 hours for liquids and >13 hours for solids. None of the children included in this study had evidence of solid content. Six (3%) children had a Grade 2 antrum (fluid content seen in both the supine and the right lateral decubitus positions). Two children had a gastric fluid volume >1.25 mL/kg. The prevalence of “at‐risk stomach” was 1% (95% confidence interval: 0.2%‐3.9%).Conclusion: According to our results, only 1% of elective children had potentially increased risk for pulmonary aspiration. Further studies should be performed in order to define the target population of elective children for which ultrasound assessment of gastric content should be performed prior to general anesthesia.