During surgery, there is a risk that food or liquid in the stomach might be forced back up the throat where it could enter the lungs (aspirate) and result in serious complications or even death. This is why people going for surgery are required not to eat before their surgery. However, in emergency situations it is often not possible to know whether a patient has recently eaten or not. Anesthesiologists have recently developed an ultrasound test to determine if there is content in a patient's stomach and how much. This test involves an ultrasound examination of the abdomen and taking some measurements on the ultrasound screen.

The purpose of this study is to determine how accurate these measurements are. In other words, how good are we at detecting an empty stomach from one that has liquids, or solids in it. You are being asked to participate in this study because we require non-pregnant volunteers in order to answer the aforementioned study question.

Inclusion Criteria:

• Healthy volunteers aged 18 to 85 years
• Male or female
• American Society of Anesthesia physical status classification I and II
• Height greater than 145 cm
• Ability to understand the study protocol and provide informed consent

Exclusion Criteria:

• Subjects predisposed to have an increased residual gastric volume at baseline (eg. Diabetes or any known dysmotility)
• History of major upper gastrointestinal disease (including hiatus hernia or prior gastroduodenal surgery)