Aspiration of gastric content is a rare but serious complication of anesthesia. In this context, preoperative fasting for elective surgery is well defined. In an emergency situation, international guidelines recommend rapid sequence of anesthesia to reduce the risk of aspiration. In semi emergency situation, there is no consensus about the anesthetic procedure even if a preoperative fasting has been observed due to uncertainty of gastric emptying related to stress or painful condition. The choice of anesthesia induction technique depends mainly on the anesthetist. Ultrasonography is a non invasive bedside tool that can provide reliable quantitative information about the volume of gastric content.

Inclusion Criteria:

• undergoing a non-elective surgery
• having a preoperative fasting period of six hours

Exclusion Criteria:

• patients with digestive diseases (gastroesophageal reflux disease, hiatal hernia, active peptic ulcer, upper gastrointestinal bleeding, vagal denervation, pyloric stenosis, extrinsic digestive compression, occlusive syndrome), neurologic diseases (spinal cord injury over T10, amylose, Shy-Drager syndrome)
• patients with full stomach (preoperative fasting under 6 hours),
• pregnant women (over 15 weeks of amenorrhea)
• patients who received premedication.