Semaglutide User Aspirated During Anesthesia Despite Extended Fasting and Residue-Free Diet | Research

The takeaway

A patient on semaglutide experienced dangerous aspiration during anesthesia induction despite following a 24-hour residue-free diet and 12-hour fast, because the drug's delayed gastric emptying effect persisted even after 6 days off the medication.

Aspiration despite 6 days off semaglutide
Even after stopping semaglutide for nearly a full week and following a strict fasting protocol, the patient's stomach still contained enough food to cause dangerous aspiration during anesthesia — demonstrating how long GLP-1 drugs can delay gastric emptying.

What the researchers found

Despite discontinuing semaglutide six days before surgery, adhering to a 24-hour residue-free diet, and completing a 12-hour fast — exceeding standard preoperative fasting guidelines — the patient experienced large-volume regurgitation during anesthesia induction requiring urgent airway management. Postoperative chest CT confirmed aspiration-related inflammatory changes in the lungs.

A critical contributing factor was the patient's failure to disclose semaglutide use during preoperative evaluation because she didn't consider it a medication. A planned preoperative gastric ultrasound was also omitted due to a protocol breach, which would have revealed retained gastric contents.

Why it matters

With tens of millions of people now using semaglutide and similar GLP-1 drugs, the risk of perioperative aspiration is a growing patient safety concern. This case shows that even measures stricter than current guidelines — including a residue-free diet and extended fasting — may not prevent the risk. It has direct implications for anesthesiologists, surgeons, and patients regarding preoperative protocols for GLP-1 users.

How the study worked

This is a single case report describing the clinical course of a 61-year-old female with obesity and COPD who experienced perioperative aspiration during elective coronary angiography. The report details the preoperative preparation, the aspiration event, imaging findings, and recovery, along with analysis of contributing factors.

What this study cannot tell us

As a single case report, this cannot establish how common aspiration events are in semaglutide users despite extended fasting. Individual factors — the patient's obesity, COPD, and the specific procedure — may have contributed to the severity. The omission of preoperative gastric ultrasound (a protocol breach) means it's unknown whether this safety measure would have prevented the complication. The exact residual gastric volume was not quantified.

How to read the evidence

This is a single case report, the lowest level of clinical evidence. However, case reports of serious adverse events like perioperative aspiration are critical safety signals that drive guideline updates and protocol changes in anesthesiology and surgery.

When this study was published

Published in 2025, this is a very recent case report directly relevant to current clinical practice as GLP-1 receptor agonist use continues to grow rapidly worldwide.

The bigger picture

This case contributes to an emerging body of safety reports about GLP-1 receptor agonists and perioperative risk. Several anesthesiology societies have issued updated guidelines recommending extended discontinuation of GLP-1 drugs before surgery, but the optimal timing remains unclear. The fact that aspiration occurred despite 6 days off the drug suggests that semaglutide's long half-life (approximately 7 days) means gastric emptying effects may persist for weeks, challenging current recommendations.

Questions still open

How long after stopping semaglutide does gastric emptying return to normal, and should preoperative discontinuation be extended beyond current guideline recommendations?
Should bedside gastric ultrasound be mandatory before all procedures requiring anesthesia in patients with any GLP-1 drug exposure?
How can preoperative screening be improved to catch undisclosed GLP-1 drug use, given that patients may not consider these medications relevant to surgery?

Common questions

Why does semaglutide increase the risk of aspiration during surgery?

Semaglutide works partly by slowing how fast food moves through the stomach (delayed gastric emptying), which helps people feel full longer and eat less. But before surgery, an empty stomach is critical — if stomach contents come back up during anesthesia when protective reflexes are suppressed, they can enter the lungs and cause serious damage. Because semaglutide's effects last long after the injection, the stomach may not fully empty even with extended fasting.

Should I stop semaglutide before surgery?

Most anesthesiology guidelines now recommend stopping GLP-1 drugs before procedures requiring anesthesia, but the optimal timing is still being debated. This case shows that even 6 days may not be enough for weekly semaglutide. Always tell your surgical team about any GLP-1 medication use — including if you've recently stopped — and ask about preoperative gastric ultrasound to check if your stomach has emptied properly.

Read the original research

Perioperative bronchoaspiration in a semaglutide user on a residue-free diet: a case report and insights from a complication.

Perioperative medicine (London, England), 14(1), 115

View on PubMed ↗Publisher’s paper ↗

Citation

Barbosa Santos, Leonardo; Muniz da Silva, Leopoldo; Silveira, Saullo Q; Nersessian, Rafael S F; Matheus, Giulia D; Mizubuti, Glenio B; Edson Vieira, Joaquim. (2025). Perioperative bronchoaspiration in a semaglutide user on a residue-free diet: a case report and insights from a complication.. Perioperative medicine (London, England), 14(1), 115. https://doi.org/10.1186/s13741-025-00603-y