[Contribution of ultrasonography for the preoperative assessment of gastric contents].

The assessment of the risk of pulmonary aspiration of gastric contents may be difficult in the preoperative period, apart from typical circumstances. The development of ultrasonography in anesthesia and critical care has led to consider ultrasonic imaging of gastric contents for preoperative risk assessment of "full" stomach in clinical practice. Ultrasonography of the body of the stomach allows direct visualization of the gastric contents. However, the stomach is often difficult to identify, particularly when it is empty. Moreover, quantitative assessment of gastric volume is delicate, and no standardized method of ultrasonography of the body of the stomach for preoperative assessment of gastric contents was described. On the contrary, ultrasonography of the antral cross-sectional area, which was initially described for the assessment of gastric emptying as an alternative method to repeated measurements of the variations of antropyloric volume after ingestion of a test meal, is easy to perform and is highly reproducible through using the aorta and the left lobe of the liver as internal landmarks. Qualitative assessment of the gastric antrum allows easily diagnosis of a "full" stomach. The measurement of antral area may allow a more accurate estimate of the presence or absence of gastric contents at risk of lung injury in the event of regurgitation and aspiration (gastric volume >0.8 ml/kg and/or with solid particles), defining the "risk" stomach. The use of antral ultrasonography may help the anesthesiologist to assess the risk of pulmonary aspiration according to clinical history of the patient, in order to choose an appropriate strategy minimizing the occurrence of this complication.