Effect of Glucagon-like Peptide-1 Receptor Agonists (GLP-1 RA) on Gastric Emptying

The Effect of Glucagon-like Peptide-1 Receptor Agonists (GLP-1 RA) on Gastric Emptying Before Elective Surgery

This study aims to assess the effect of using Glucagon-like peptide-1 receptor agonists (GLP-1) receptor agonists on gastric emptying on surgical patients and whether specific guidelines need to be established for these patients. GLP-1 receptor agonists are mainly used for the treatment and mitigation of obesity and metabolic syndromes. One of their mechanisms of action is by delaying gastric emptying, hence increasing satiety. However, patients need to abstain from eating for a set amount of time before surgery to reduce the risk of aspiration. Hence patients who use GLP-1 receptor agonists may need more time to abstain eating (nil-per-os). In this study we aim to assess how much time is sufficient before surgery in these specific population of patients.

Diabetes is a global health issue. It is the leading cause of death and disability worldwide. More than 1.31 billion people are projected to have diabetes in the world by 2050. Similarly in the United States total prevalence of diabetes is projected to be around 21% of the US population by 2050. Glucagon-like peptide-1 receptor agonists (GLP-1 RA), alternatively referred to as incretin mimetics, or GLP-1 analogs, constitute a category of drugs utilized for the management of type 2 diabetes mellitus and also for obesity. Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are hormones known as incretin hormones. GIP hormones play a role in stimulating the release of insulin after consuming glucose, which is referred to as the incretin effect. However, in people with type 2 diabetes, this process can be diminished or absent. Pharmacological levels of GLP-1 can help restore insulin secretion in individuals with type 2 diabetes. The advantages of using this approach for treating type 2 diabetes include the slowing down of stomach emptying and the suppression of glucagon production from pancreatic alpha cells when blood sugar levels are high. Additionally, GLP-1 RAs have the potential to reduce the death of pancreatic beta cells (the cells responsible for producing insulin) while also encouraging their growth.

Recent literature have raised concerns about the potential of GLP-1 RA-induced delayed gastric emptying to heighten the risk of regurgitation and inhalation of stomach contents during instances of general anesthesia and profound sedation. The term "high-risk stomach" refers to gastric volume carrying a heightened pulmonary aspiration risk, typically defined as liquid content exceeding 1.5 ml/kg or the presence of solid matter, as commonly described in literature. Gastric ultrasound has been used as an important tool for assessing the gastric content and volume. Measurement of the antral cross-sectional area by ultrasound with subsequent calculation of gastric volume can determine the low risk or high-risk stomach accordingly (8.

In June 2023, the ASA (American Society of Anesthesiologists) released a consensus-based guideline regarding the preoperative management of patients using GLP-1 RA. The recommendation advised taking these medications either on the day before or on the day of the procedure. Patients on a weekly regimen were advised to suspend the drug for the entire week. Although there are general fasting recommendations for the general population, no fasting recommendations were provided for patients on GLP-1 RA due to insufficient supporting evidence.

This research aims to increase our understanding about the effect of use of GLP-1 RAs on gastrointestinal motility and gastric emptying. The results of this study may provide insight regarding acceptable timing of NPO (Non per oral) before surgical procedures to reduce the risk of aspiration and other related complications.

The following information will be obtained from the patients in their visit:

1. Patient's identifying information
2. Patient's age
3. Patient's gender
4. Patient's weight
5. Time of last eating or drinking
6. Consumed food in the last eating or drinking
7. Duration of fasting
8. Patient's procedure/surgery
9. Medical history, including Previous gastric resection or bypass, Previous fundoplication, Gastric band in situ, Large hiatus hernia, Pregnancy, GERD
10. Any relevant surgical history, history of substance use, and list of current medications
11. Name of GLP-1 receptor agonist drug and its brand name
12. Dose of the medication
13. Dosing interval of the medication
14. Route of administration of the medication
15. Duration of use of the medication since the first dose
16. Last time of drug administration
17. Reason for continuing GLP-1 receptor Agonist drug, including diabetes, weight loss, etc

Gastric Ultrasound Finding reporting items:

1. Whether the stomach is empty or not
2. Whether the stomach has liquid content or not
3. The right lateral antral cross-sectional area (CSA)
4. Calculated gastric volume
5. Whether the stomach has solid food

Inclusion Criteria:

• Adult patients who are receiving Glucagon-like peptide-1 Receptor Agonist medication and scheduled for any elective surgery or procedure under anesthesia.
• The patient has provided informed consent for the study

Exclusion Criteria:

• Pregnant patients
• Patients with abnormal gastric anatomy like previous gastric resection or bypass( gastric band in situ, previous fundoplication, hiatus hernia
• Inability to consent
• Emergency surgery
• Cognitive impairment (due to the mixed reasons of potential misunderstanding of the aim of the study and inability to provide informed consent, potential inability to provide detailed fasting regimen before the surgery, potential for impaired use of GLP-1 agonists before the surgery)
• Terminal illness (due to the effect of chronic illness on the physiologic functions of gastrointestinal tract and gastric emptying)