Authors: Pai S-L et al.
Anesthesia & Analgesia, 142(4):640–649, April 2026
This study evaluated residual gastric contents (RGC) using point-of-care gastric ultrasound in patients taking glucagon-like peptide-1 receptor agonists (GLP-1 RAs), with the goal of identifying factors associated with increased aspiration risk before anesthesia.
GLP-1 RAs are increasingly used for diabetes and weight loss and are known to delay gastric emptying. This raises concern for residual gastric contents despite standard fasting, creating uncertainty in perioperative management.
In this multicenter observational study, 316 adult patients on GLP-1 RAs underwent preoperative gastric ultrasound. High RGC was defined as either solid contents or more than 1.5 mL/kg of clear fluid. The results are clinically significant: 35.8% of patients had high residual gastric contents despite fasting.
Several key factors were associated with increased RGC. Patients who withheld their GLP-1 RA for a shorter duration were more likely to have high gastric contents. Specifically, withholding the medication for ≤7.5 days was associated with increased risk. Similarly, shorter fasting duration from solid food was associated with higher RGC, with a cutoff of ≤21.3 hours.
Interestingly, most traditional risk factors did not differ between groups. There were no significant differences based on indication for GLP-1 use, duration of therapy, or comorbidities. However, recent opioid use was more common in patients with high RGC, suggesting a potential additive effect on delayed gastric emptying.
These findings highlight a major issue: standard fasting guidelines may not be sufficient for patients on GLP-1 RAs. Even with prolonged fasting (median up to 15–20 hours), a substantial proportion of patients still had significant gastric contents.
The study supports the growing role of gastric ultrasound as a valuable bedside tool for risk stratification. Given the variability in gastric emptying in this population, individualized assessment may be more appropriate than relying solely on time-based fasting guidelines.
Limitations include the observational design and inability to directly link ultrasound findings to aspiration events. However, the high prevalence of residual contents is concerning enough to influence clinical practice.
Key Points
- Over one-third of patients on GLP-1 RAs had high residual gastric contents despite fasting
- Withholding GLP-1 RA for ≤7.5 days increases risk of delayed gastric emptying
- Fasting ≤21.3 hours from solid food is associated with higher gastric content
- Traditional risk factors were not predictive, except recent opioid use
- Gastric ultrasound is a valuable tool for perioperative risk assessment
What You Should Know
This is one of the most important perioperative topics right now. Standard fasting rules do not reliably apply to patients on GLP-1 medications. Even after long fasting periods, a significant number of patients still have full stomachs. If you are not thinking about aspiration risk differently in these patients, you should be. Gastric ultrasound is quickly becoming the tie-breaker when the history is unclear or concerning. Expect evolving guidelines—but for now, caution and individualized assessment are the safest approach.
We want to thank Anesthesia & Analgesia for allowing us to summarize and share this important work with the anesthesia community.