This prospective observational study will evaluate the association between the time interval since the last dose of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and residual gastric contents before elective surgery. Adult patients receiving GLP-1 RAs and scheduled for elective non-cardiac surgery under general anesthesia will undergo preoperative point-of-care gastric ultrasound. The study will assess whether longer GLP-1 RA cessation intervals are associated with lower ultrasound-estimated gastric volume and a lower frequency of high-risk gastric contents. Body mass index will also be evaluated as a potential modifier of this association.

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are increasingly used for the treatment of type 2 diabetes and obesity. These agents can delay gastric emptying, raising concerns about residual gastric contents and potential aspiration risk during anesthesia. Current perioperative recommendations regarding GLP-1 RA discontinuation are largely consensus-based, and the physiological relationship between cessation interval and residual gastric content remains insufficiently defined.

This single-center prospective observational cohort study will enroll adult patients who are receiving GLP-1 RAs and are scheduled for elective non-cardiac surgery requiring general anesthesia. GLP-1 RA management will follow usual clinical care; the study team will not assign, modify, or instruct the timing of drug discontinuation. The primary exposure will be the number of days since the last GLP-1 RA dose, analyzed both as a continuous variable and according to prespecified cessation-interval categories.

Immediately before induction of anesthesia, participants will undergo standardized point-of-care gastric ultrasound. Qualitative gastric content will be assessed using the Perlas grading system, and quantitative gastric volume will be estimated from the antral cross-sectional area measured in the right lateral decubitus position. The primary outcome will be estimated gastric volume normalized to body weight. Secondary outcomes will include antral cross-sectional area, Perlas grade, and the presence of high-risk gastric contents.

Multivariable regression models will be used to evaluate the association between GLP-1 RA cessation interval and gastric ultrasound findings after adjustment for clinically relevant covariates, including age, sex, body mass index, diabetes status, preoperative fasting duration, and gastrointestinal symptom score. Body mass index will be evaluated as a prespecified effect modifier.

Inclusion Criteria:

• Adults aged 18 years or older.
• Patients receiving a glucagon-like peptide-1 receptor agonist.
• Patients scheduled for elective non-cardiac surgery requiring general anesthesia.
• Patients able to provide written informed consent.

Exclusion Criteria:

• Emergency surgery.
• History of prior gastric surgery.
• Known gastroparesis or severe gastroesophageal reflux disease.
• Declined or unable to provide written informed consent.

Adult patients receiving glucagon-like peptide-1 receptor agonists who are scheduled for elective non-cardiac surgery requiring general anesthesia at a tertiary academic hospital. Participants will be screened consecutively by the perioperative anesthesia team and enrolled if eligibility criteria are met.