Glucagon Like Peptide-1 Receptor Agonist Use Not Related With Gastric Volume After Preoperative Fasting: A Prospective Observational Study

INTRODUCTION: Glucagon-like peptide-1 receptor agonist (GLP-1 RA) use has increased, with approximately 12% of US adults having used these agents. Glucagon-like peptide-1 receptor agonist decelerate gastric emptying, raising concern for perioperative aspiration. Therefore, the goal of this study was to evaluate whether perioperative gastric volumes varied between participants receiving and not receiving GLP-1 RA. MATERIALS AND METHODS: Between 2023 and 2025, volunteer participants were enrolled in this observational prospective study if scheduled for surgery, over 18 years of age, and were free of any exclusion criteria. For those in the group of interest, participants were also on injectable, pure GLP-1 RA therapy. An investigator performed a gastric ultrasound and the cross-sectional area (CSA) of the antrum was determined. Gastric volume was then calculated using the formula: gastric volume = 27.0 + 14.6 x CSA-1.28 x age. The primary outcome was gastric volume in the right lateral decubitus position; the secondary outcome was weight-adjusted gastric volume. RESULTS: Of the 117 included participants, 60 were in the GLP-1 RA group and 57 were in the control group. Participants in the GLP-1 RA group had a median [IQR] 189 days [80; 366] duration of GLP-1 RA use and received their last GLP-1 RA dose a median [IQR] 9 days [7.5; 13] before surgery. Participants in the GLP-1 RA group had a higher median age (P = 0.01), were more likely to have an American Society of Anesthesiologists (ASA) physical status level of III-IV relative to I-II (P = 0.03), and were more likely to have a diabetes diagnosis (P < 0.01), compared to participants in the control group. Therefore, these variables were included as covariates in generalized additive models. Solid contents were observed in 13 participants, with similar distributions between groups (P = 1.00); their data was not included in the generalized additive models. The GLP-1 RA (n = 53) and control (n = 51) groups did not significantly differ in gastric volumes (-2.65, 97.5% CI -26.48 to 21.18, P = 0.81) or weight-adjusted gastric volumes (-0.03, 97.5% CI -0.26 to 0.20, P = 0.79). Younger age and higher ASA physical status levels were associated with greater gastric volume. The findings replicated in the propensity score weighting sensitivity model. CONCLUSIONS: There was a lack of significant differences in gastric volume between participants who were and were not taking GLP-1 RA medications, with most participants in the GLP-1 group having discontinued medications for at least 1 week.