Gastric Emptying in Healthy Volunteers and GLP-1 Agonist Users

Gastric Emptying Assessed by Gastric Ultrasound (US) in Healthy Volunteers and Semaglutide Users: Cohort Study

This observational study aims to determine the gastric emptying kinetics assessed by ultrasound in healthy volunteers after a standard breakfast and the state of the stomach after a clear liquid diet for 18 /24 hours in patients on GLP-1 agonist. The main questions it seeks to answer are:

• Is the kinetic after a standard breakfast that includes ( avocado and eggs: high fat) as fast as a standard meal that does not involve this food?
• Is a clear liquid diet of 18 to 24 hours enough to be an empty-stomach, assessed by Ultrasound in patients on GLP1 agonist?

Participants will be asked to do:

-A baseline Gastric US will be performed for healthy volunteers, and then they will have a standardized breakfast. An hourly or bihourly assessment will be done by the US.

GLP-1 analogues enhance insulin secretion from β-cells, reduce glucagon secretion, have an appetite-suppressing effect, and delay gastric emptying. This last effect may make standard preoperative fasting inadequate, compromising airway safety during elective surgery and increasing aspiration risk.

The main goal is to gather evidence to determine the optimal fasting period and dietary regimen to ensure safe outpatient surgery without increasing the risk of aspiration.Ultrasound gastric content assessment is a highly accessible, bedside, cost-free, and low-risk tool for anesthesiologists. The increased use of these drugs in surgical patients and the lack of international consensus on their discontinuation and fasting protocols before surgery necessitate further study. Our hypothesis is that GLP-1 analogue users (for weight loss or diabetes) have significantly slower gastric emptying, but a 24-hour liquid regimen may be sufficient to ensure an empty stomach and safe elective surgery.

Inclusion Criteria:

• 18 years old or older
• Healthy volunteers or semaglutide users

Exclusion Criteria:

• Bariatric surgery
• Hiatal hernia
• Impairment to give consent