Safety concerns for patients undergoing anaesthesia who use glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have been revealed in a study by researchers from the University of Texas Health Science Center at Houston. The study was led by first author Dr Sudipta Sen, associate professor, and senior author and Professor Omonele Nwokolo, both from the Department of Anesthesiology, Critical Care and Pain Medicine at McGovern Medical School at UTHealth Houston.
"Our findings were quite surprising. More than half of the patients on a GLP-1 RA had significant gastric contents on gastric ultrasound before an elective procedure, despite adhering to preoperative fasting," explained Sen. "This incidence was significantly higher compared to patients not on a GLP-1 RA, showing a strong link between GLP-1 RA drugs and potential aspiration risk under anaesthesia."
The study was prompted by internal quality reviews led by Nwokolo and associate professor in the department, Dr Srikanth Sridhar, after anecdotal cases of aspiration under anaesthesia were reported by staff for patients taking this class of medications for weight loss, despite adequate fasting before the procedure. Aspiration is a potentially dangerous condition where stomach contents enter the lungs.
Sen and study co-authors, associate professor Dr Nadia Hernandez, and assistant professor Dr Christina Goehl, who are subspecialised anaesthesiologists with expertise in point-of-care ultrasound that allows bedside assessment of stomach contents. One mechanism of GLP-1 RA medications central to weight loss and glycaemic control is slowing of the emptying of gastric contents from the stomach. This increase in residual gastric volumes is identified as a "full stomach" on gastric ultrasound.
This study, designed by assistant professor Dr Paul Potnuru, examined more than 120 patients scheduled for elective procedures between June and July 2023. Findings revealed that 56% of patients using GLP-1 RAs exhibited increased residual gastric content, compared to 19% of those who did not take the medication. The study further indicated a 30.5% prevalence of increased residual gastric content with the use of GLP-1 RAs.
With the increasing use of GLP-1 RA medications and their expanding indications for treating various conditions, Sen said conventional fasting times for this patient subset may need to be re-examined.
"Patients must ensure they disclose their use of this medication to their surgeons and anaesthesiologists," Sen added. "This information is crucial for us to provide appropriate recommendations, such as adjusting drug administration before elective procedures, recommending extended fasting, or rescheduling an elective procedure if necessary."
In June 2023, the American Society of Anesthesiologists’ TaskForce released new guidance for screening GLP-1 RA use before surgery and informing patients of the risk of adverse outcomes. Recommendations included the consideration of pausing GLP-1 RAs prior to elective surgery.
"Our study fills a significant gap in the current understanding and management of patients on GLP-1 RAs undergoing surgery," said Nwokolo. "The lack of data had previously led societies to rely on expert opinion for guidance. Our evidence paves the way for informed guidelines and further research to mitigate anaesthesia-related risks in this patient population."
The study's outcomes prompt a re-evaluation of preoperative protocols in this subset of patients, underscoring the significance of patients openly communicating their GLP-1 RA use before surgery.
The findings were reported the study, ‘Glucagon-Like Peptide-1 Receptor Agonist Use and Residual Gastric Content Before Anesthesia’, published in JAMA Surgery. To access this paper, please click here (login maybe required)