PURPOSE: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) delay gastric emptying, potentially increasing aspiration risk during anesthesia or sedation. Guidelines for withholding these agents before procedures remain inconsistent. This study prospectively evaluated whether prolonged fasting or time since the last GLP-1 RA dose more effectively predicts reduced solid gastric content and other indicators of aspiration risk.
METHODS: This prospective observational study enrolled 134 adults (74 GLP-1 RA users, 60 controls) from an internal medicine clinic, fasting 8-16 h. Point-of-care ultrasound (POCUS) was used to assess gastric antral content, cross-sectional area, and gastric volume (GV). Analyses included subgroup comparisons and multivariable regression adjusting for fasting duration, GLP-1 dose, and timing.
RESULTS: Solid gastric content was similar between GLP-1 users (4/74, 5.4%) and controls (3/60, 5.0%) (p = 0.563). Mean fasting duration was 13.0 ± 2.4 h. Among GLP-1 users, those with solids had shorter fasting times than those without (10.88 ± 0.75 vs. 13.14 ± 2.40 h; Welch's t-test p = 0.022, permutation p = 0.0684). Longer fasting trended toward lower odds of solids (OR = 0.61, p = 0.075). Fasting duration demonstrated a stronger inverse association with GV (β = - 2.26 mL/h) than time since last GLP-1 dose, which was not significant.
CONCLUSIONS: Fasting duration, rather than time since last GLP-1 dose, was more closely associated with reduced gastric content and volume. These findings support individualized fasting strategies and POCUS-based assessment over routine medication withholding for perioperative safety.
