Assessment of preoperative gastric content with ultrasound in patients taking GLP-1 receptor agonists: an observational, multicenter, cross-sectional study

Background Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) delay gastric emptying, and there have been incidents of pulmonary aspiration in patients who had followed standard preoperative fasting instructions while on GLP-1 RA therapy. As the use of GLP-1 RAs is rising, we aim to compare the preoperative gastric contents of elective surgical patients taking GLP-1 RAs with those not taking these medications. Secondary objectives were to study the association of the indication, dose, time since last dose, and hours of fasting with gastric content. Methods This cross-sectional, multi-center study included elective surgery patients taking weekly GLP-1 RA medications for all indications, and those not taking them. All patients underwent standardized bedside gastric ultrasound preoperatively. Statistical analysis included χ2 or Fisher’s exact testing, Mann-Whitney U testing, and a multivariable logistic regression of full stomach on GLP-1 RA users, controlling for potential confounders where data were available. Results A total of 354 patients were enrolled from August 29, 2023, to January 31, 2025. A total of 307 patients were analyzed, 151 in the GLP-1 RA group, and 156 in the non-GLP-1 RA group. The occurrence of a full stomach was not significantly different between groups (13.9% vs 10.3%, p=0.38). Adjusted regression analysis also did not show a significant difference in fullness between groups (p=0.61). Patients in the GLP-1 RA group had a significantly longer solid fasting time than the non-GLP-1 RA group (median (Q1, Q3): 18.5 (13.5, 25.45) vs 15.98 (14.27, 17.55) hours; p=0.002). Treatment indication, time since last dose, and duration were not significantly associated with the occurrence of full stomach. Conclusions This study found no difference in the occurrence of full stomach in elective surgical patients taking GLP-1 RAs compared with the non-GLP-1 RA group. A longer solid fasting time in the GLP-1 RA group may have contributed to this finding. Our results also indicate that longer fasting times alone may not eliminate the risk of full stomach in patients taking GLP-1 RAs. Trial registration number NCT06003985.