Ultrasound Assessment of Gastric Emptying After a Standardized High Calorie Liquid Meal in Adults: a Prospective Observational Double-blind Study

Perioperative fasting is an essential patient safety measure to reduce the risk of pulmonary aspiration of gastric contents, a rare but potentially catastrophic complication of anesthetic and airway management. Anesthesiologists' concern about aspiration and the increasing awareness towards the negative impact of prolonged restriction of oral intake have shaped the current fasting guidelines. However, due to the perceived safety of prolonged fasting and practical considerations, adoption of the fasting guidelines is suboptimal.

Gastric ultrasound is a quick, non-invasive method to evaluate gastric contents and aspiration risk. Gastric ultrasound can accurately discriminate between solid particles and fluid content, and mathematical models can reliably predict the volume of the gastric contents from the gastric antral area (GAA).

This project aims to use gastric ultrasound to provide new data that can support management strategies in perioperative patients, that ensure both a low aspiration risk and an adequate nutritional support.

The investigators will test the hypothesis that commercially available liquid meals can be safely used preoperatively. A pilot crossover, study on healthy volunteers will be conducted to determine the gastric emptying time of high-calorie drinks, as compared to clear fluid.