GLP-1 RA Cessation and Gastric Ultrasound Findings

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.

• GLP-1 RA Cessation Interval (Other), also known as Time Since Last GLP-1 RA Dose, GLP-1 RA Discontinuation Interval: Observed exposure defined as the number of days between the participant's last glucagon-like peptide-1 receptor agonist dose and elective surgery. Participants were categorized according to time since last dose: 3 days or less, 4 to 7 days, and 8 days or more. No GLP-1 receptor agonist was assigned, administered, continued, or discontinued by the study protocol; medication management followed usual clinical care.

Primary outcomes

• Estimated Gastric Volume Normalized to Body Weight [Immediately before induction of anesthesia on the day of surgery]: Estimated gastric volume normalized to body weight, expressed as mL/kg, calculated from the antral cross-sectional area measured by preoperative point-of-care gastric ultrasound in the right lateral decubitus position.

Secondary outcomes

• Antral Cross-Sectional Area [Immediately before induction of anesthesia on the day of surgery]: Antral cross-sectional area measured by preoperative point-of-care gastric ultrasound in the right lateral decubitus position and expressed in cm2.
• Perlas Gastric Ultrasound Grade [Immediately before induction of anesthesia on the day of surgery]: Qualitative gastric content will be assessed using the Perlas Gastric Ultrasound Grading System, which ranges from Grade 0 to Grade 2. Grade 0 indicates an empty stomach, Grade 1 indicates fluid visible only in the right lateral decubitus position, and Grade 2 indicates fluid visible in both the supine and right lateral decubitus positions. Higher grades indicate greater residual gastric content.
• Gastrointestinal Symptom Score [Within 24 hours before surgery]: Preoperative gastrointestinal symptoms will be assessed using a Gastrointestinal Symptom Numeric Rating Scale for nausea, vomiting, bloating, early satiety, and abdominal discomfort. Each symptom is rated from 0 to 10, where 0 indicates no symptom and 10 indicates the worst imaginable symptom. The total score ranges from 0 to 50, with higher scores indicating more severe gastrointestinal symptoms.

Sex: All, ages: 19 Years to 65 Years

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.

• Cheol Lee, M.D.,Ph.D, Study director, Wonkwang University Hosptial