Ultrasound Shows Many GLP-1 Drug Users Still Have Food in Their Stomachs Before Surgery

Nearly half of patients on GLP-1 receptor agonists had significant residual gastric contents before anesthesia, raising concerns about aspiration risk during surgery.

Pai, Sher-Lu et al.·Anesthesia and analgesia·2025·Moderate EvidenceProspective Cohort
RPEP-12919Prospective CohortModerate Evidence2025RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Prospective Cohort
Evidence
Moderate Evidence
Sample
N=316
Participants
N=316 adults on GLP-1 receptor agonists scheduled for anesthesia at 3 US hospitals, June 2023 to August 2024. Median age 60.9, 52.8% female.

What This Study Found

A substantial proportion of patients on GLP-1 receptor agonists had high residual gastric contents before anesthesia despite standard fasting, suggesting current preoperative fasting guidelines may be inadequate for this population.

Key Numbers

  • 316 patients studied; 35.8% had high residual gastric contents
  • Weekly injection withholding: 8 days (low RGC) vs 6 days (high RGC), p=0.003
  • Cutoff: 7.5 days of withholding weekly injections
  • Solid food fasting: 20 hours (low RGC) vs 15 hours (high RGC), p<0.001
  • Cutoff: 21.3 hours fasting from solids
  • Opioid use: 5.3% (high RGC) vs 1.0% (low RGC), p=0.027

How They Did This

Prospective cohort study across 3 hospitals. Adult patients taking GLP-1 RAs and scheduled for anesthesia underwent preoperative gastric ultrasound to assess residual gastric contents (RGC). Preoperative factors associated with high RGC were evaluated.

Why This Research Matters

With millions now taking GLP-1 drugs for diabetes and weight loss, the surgical safety implications are enormous. Delayed gastric emptying increases the risk of pulmonary aspiration during anesthesia — a potentially life-threatening complication.

The Bigger Picture

As GLP-1 receptor agonists become one of the most prescribed drug classes worldwide, this study underscores the urgent need for anesthesiology guidelines to adapt. The findings have implications for the millions of patients on semaglutide, liraglutide, and similar drugs who may need surgery.

What This Study Doesn't Tell Us

Sample size and specific prevalence numbers not provided in abstract; ultrasound assessment is operator-dependent; did not directly measure aspiration events, only risk indicators; may not account for all GLP-1 RA types and doses.

Questions This Raises

  • ?Should patients stop GLP-1 drugs days or weeks before surgery to allow gastric motility to normalize?
  • ?Are certain GLP-1 receptor agonists (weekly vs. daily formulations) associated with greater gastric retention?
  • ?What is the optimal fasting duration for GLP-1 RA users before anesthesia?

Trust & Context

Key Stat:
3 hospital sites Multi-center study assessing gastric contents in GLP-1 RA patients before anesthesia
Evidence Grade:
Prospective multi-center cohort study providing moderate clinical evidence. Directly relevant to patient safety but would benefit from larger randomized studies.
Study Age:
Published in 2025 with data from 2023 onward, reflecting the current era of widespread GLP-1 RA use.
Original Title:
Assessment of Gastric Content Using Gastric Ultrasound in Patients on Glucagon-Like Peptide-1 Receptor Agonists Before Anesthesia.
Published In:
Anesthesia and analgesia (2025)
Database ID:
RPEP-12919

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-ControlFollows or compares groups over time
This study
Cross-Sectional / Observational
Case Report / Animal Study

Enrolls participants and follows them forward in time.

What do these levels mean? →

Frequently Asked Questions

Should I stop my GLP-1 medication before surgery?

This study suggests GLP-1 drugs can delay stomach emptying significantly. Many anesthesiology societies now recommend holding GLP-1 medications before surgery, but you should consult your doctor for specific guidance based on your medication and procedure.

What happens if your stomach isn't empty during surgery?

If there is food or liquid in your stomach during anesthesia, it can come back up and enter your lungs (aspiration), which can cause serious breathing problems or pneumonia. That's why fasting before surgery is important.

Read More on RethinkPeptides

Cite This Study

RPEP-12919·https://rethinkpeptides.com/research/RPEP-12919

APA

Pai, Sher-Lu; Nimma, Sindhuja R; Beam, W Brian; VanderWielen, Beth A; Kalagara, Hari K; Bettini, Layne M; Yu, Soojie; Sharpe, Emily E; Harbell, Monica W. (2025). Assessment of Gastric Content Using Gastric Ultrasound in Patients on Glucagon-Like Peptide-1 Receptor Agonists Before Anesthesia.. Anesthesia and analgesia. https://doi.org/10.1213/ANE.0000000000007764

MLA

Pai, Sher-Lu, et al. "Assessment of Gastric Content Using Gastric Ultrasound in Patients on Glucagon-Like Peptide-1 Receptor Agonists Before Anesthesia.." Anesthesia and analgesia, 2025. https://doi.org/10.1213/ANE.0000000000007764

RethinkPeptides

RethinkPeptides Research Database. "Assessment of Gastric Content Using Gastric Ultrasound in Pa..." RPEP-12919. Retrieved from https://rethinkpeptides.com/research/pai-2025-assessment-of-gastric-content

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.