Time-dependent Association Between Cessation of Glucagon-like Peptide-1 Receptor Agonists and Residual Gastric Contents Assessed by Point-of-care Gastric Ultrasound: a Prospective Observational Study

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.