HSS Studies Highlight Challenges in Stomach Assessment Before Surgery as GLP-1 and Cannabis Use Increase

NEW YORK--(BUSINESS WIRE)--As the use of GLP-1 medications and cannabis becomes more common, anesthesiologists are facing new questions about how best to assess whether a patient's stomach is empty before surgery. Two studies from Hospital for Special Surgery (HSS), presented at the 2026 European Society of Regional Anaesthesia and Pain Therapy (ESRA) Congress, suggest current approaches to evaluating aspiration risk may not always provide clear answers.

What follows are highlights from these studies:

Association of GLP-1 Receptor Agonist Medication Duration of Use and Withholding Time with Predicted Probability of Preoperative Full Stomach

GLP-1 receptor agonists, including medications commonly prescribed for diabetes and weight management, can delay gastric emptying, raising concerns that patients may still have food or liquid in their stomach at the time of surgery. This can increase the risk of aspiration, a potentially serious complication during anesthesia.

In a multicenter study, researchers examined whether GLP-1 receptor agonist use and medication withholding times were associated with the likelihood of a full stomach before surgery. While patients taking GLP-1 medications had slightly higher rates of a predicted full stomach than those not taking the medications, the difference was smaller than expected. Researchers noted that prolonged fasting before surgery may have contributed to the findings, though fasting alone did not eliminate the risk, as some full-stomach patients in the GLP-1 group had fasted for more than 23 hours.

“As concerns have grown about delayed gastric emptying in patients taking GLP-1 medications, many clinicians have looked to longer fasting times as a potential strategy to reduce risk,” said Oliver Panzer, MD, anesthesiologist at HSS and co-author of the study. “Our findings suggest that extended fasting may help reduce the likelihood of a full stomach, but it is unlikely to eliminate the risk entirely. However, because this was an observational study, we cannot conclude that longer fasting times directly caused the lower rates of full stomach observed in some patients. Additional research is needed to better understand the factors that influence gastric emptying and perioperative risk in patients taking GLP-1 medications.”

Interrater Reliability of Preoperative Gastric Ultrasound in Patients Using Cannabis

Gastric ultrasound is increasingly used before surgery to help determine whether a patient's stomach is empty or still contains food or fluid that could increase aspiration risk during anesthesia. Although established guidelines exist for interpreting these ultrasound images, researchers found that assessing stomach contents in patients who use cannabis may be more challenging than expected.

The study's key finding was poor agreement among four experienced point-of-care ultrasound clinicians reviewing gastric ultrasound images, suggesting that existing ultrasound criteria may not always provide clear guidance in patients who use cannabis. One potential challenge is the presence of air in the gastric antrum, which can appear in both empty and full stomachs and may complicate interpretation.

“We found considerable variation among experienced clinicians reviewing the same ultrasound images,” said Stephen Haskins, MD, anesthesiologist at HSS and co-author of the study. “The findings suggest that additional refinement of gastric ultrasound criteria may be needed to improve consistency, reduce uncertainty, and support clearer perioperative decision-making.”

Implications for Preoperative Decision-Making

Together, these studies underscore the growing complexity of preoperative stomach assessment as patient populations and medication-use patterns evolve. The GLP-1 study suggests that longer fasting periods may help reduce the risk of a full stomach before surgery, though fasting alone may not completely eliminate risk. Meanwhile, the cannabis study highlights potential limitations in current gastric ultrasound criteria.

Collectively, the findings suggest that assessing aspiration risk may require a more individualized approach and that additional research is needed to refine the tools and guidelines clinicians use to make perioperative decisions. Researchers hope the studies will help inform future efforts to improve patient safety and anesthesia care.

About HSS

HSS is the world’s leading academic medical center focused on musculoskeletal health. At its core is Hospital for Special Surgery, nationally ranked No. 1 in orthopedics (for the 17th consecutive year), No. 3 in rheumatology by U.S. News & World Report (2026-2027), and the best pediatric orthopedic hospital in NY, NJ and CT by U.S. News & World Report “Best Children’s Hospitals” list (2026-2027). HSS is the worlds most awarded hospital in orthopedics by Newsweek each year since the “World’s Best Specialized Hospitals” survey was introduced in 2020. Founded in 1863, the Hospital has the lowest readmission rate in the nation, and among the lowest infection and complication rates. HSS was the first in New York State to receive Magnet Recognition for Excellence in Nursing Service from the American Nurses Credentialing Center six consecutive times. An affiliate of Weill Cornell Medical College, HSS has a main campus in New York City and facilities in New Jersey, Connecticut and in the Long Island and Westchester County regions of New York State, as well as in Florida. In addition to patient care, HSS leads the field in research, innovation and education. The HSS Research Institute comprises 20 laboratories and 300 staff members focused on leading the advancement of musculoskeletal health through prevention of degeneration, tissue repair and tissue regeneration. In addition, more than 200 HSS clinical investigators are working to improve patient outcomes through better ways to prevent, diagnose, and treat orthopedic, rheumatic and musculoskeletal diseases. The HSS Education Institute is a trusted leader in advancing musculoskeletal knowledge and research for physicians, nurses, allied health professionals, academic trainees, and consumers in more than 165 countries. The institution is collaborating with medical centers and other organizations to advance the quality and value of musculoskeletal care and to make world-class HSS care more widely accessible nationally and internationally. www.hss.edu.