This project investigates the risk of pulmonary aspiration during anesthesia in patients undergoing treatment with GLP-1 agonists, a class of medications that prolong gastric emptying and are commonly used for obesity and diabetes management. Pulmonary aspiration remains a significant cause of morbidity and mortality in anesthesia-related complications, and patients with delayed gastric emptying are at higher risk. Recent reports suggest that patients taking GLP-1 agonists may be at increased risk for aspiration, even when adhering to standard perioperative fasting guidelines (6 hours for solids, 2 hours for liquids).
The American Society of Anesthesiologists (ASA) has issued a warning about the potential risk of aspiration in patients on GLP-1 agonist therapy, recommending pausing the medication before surgery. However, this recommendation has been criticized for being too broad, given the lack of comprehensive data on the exact impact of GLP-1 agonists on gastric emptying and aspiration risk. Since many patients treated with GLP-1 agonists are already at higher risk of aspiration due to comorbidities like obesity and diabetes, understanding how this therapy further affects gastric function is crucial. There are also indications of a "tachyphylaxis" effect, where patients develop tolerance to the drug's impact over time, but its effect on gastric emptying and perioperative aspiration risk is not well understood.
Study Rationale and Objectives
The primary aim of this study is to assess whether patients undergoing GLP-1 agonist therapy have a higher likelihood of a full stomach after the recommended fasting intervals. Additionally, the study aims to evaluate the time taken for gastric emptying in these patients, focusing on the clearance of 500 ml of water.
Study Design
The project is a national, single-center, prospective observational study that will include approximately 50 patients who are starting GLP-1 agonist therapy. Patients will serve as their own control group by undergoing gastric ultrasound before beginning treatment and then again 6-8 weeks after therapy initiation. If therapy is continued, a follow-up ultrasound will occur around 5 months later.
The ultrasound examinations will measure both the gastric content (solid, liquid, or empty) and the cross-sectional area (CSA) of the gastric antrum to estimate gastric volume. These measurements will provide insight into whether patients on GLP-1 agonists have prolonged gastric emptying, contributing to the risk of aspiration during surgery.
Study Population and Procedures
The study population will consist of patients prescribed GLP-1 agonists for obesity, diabetes, or lifestyle reasons. Inclusion criteria include adults beginning a new GLP-1 therapy regimen, while exclusion criteria rule out patients with known gastrointestinal disorders, previous GI surgery, pregnancy, and those at high risk for hypoglycemia due to other medications like sulfonylureas or insulin.
Recruitment will occur through collaboration with the Adipositas und StoffwechselZentrum Hirslanden Zurich, where GLP-1 agonists are regularly prescribed. Patients will be contacted by phone to provide initial study information, and written informed consent will be obtained before the baseline examination. A demographic and medical history will also be collected at the initial visit.
