Preoperative Metoclopramide to Enhance Gastric Emptying in Patients on Glucagon-Like Peptide-1 Receptor Agonists for Weight Loss: A Randomised Controlled Trial With Ultrasound Assessment

The increasing use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) for weight loss has created a new challenge for anaesthesiologists: delayed gastric emptying in patients who appear to be fasted, which may increase their risk of pulmonary aspiration under anaesthesia. While consensus statements recommend assessing aspiration risk and implementing mitigation strategies, there is limited clinical trial evidence to support these practices.

This is a multicentre, prospective, single-blinded, randomised controlled trial designed to assess whether preoperative oral metoclopramide can reduce residual gastric content (RGC) in patients taking GLP-1 RAs prior to elective surgery. Eighty adult patients who are taking GLP-1 RAs for weight loss will be enrolled and randomly assigned in a 1:1 ratio to either standard care or standard care plus metoclopramide. Standard care is defined as continuation of GLP-1 RA medications as per current perioperative guidance. The intervention group will receive four doses of oral metoclopramide 10 mg: three doses the day before surgery and one dose on the morning of surgery.

The primary outcome for this randomised controlled trial will be the presence of residual gastric content (RGC) [yes/no] on gastric ultrasound examination in fasting patients taking GLP-1 agonists, scheduled for elective surgery. Our primary outcome will be a binary outcome, and we will define the presence of RGC as one or more of the following present on gastric ultrasound examination: 1. Presence of solid; 2. Presence thick fluid; and 3. > 1.5ml/kg of clear fluid.

Based on a recent published prospective cross-sectional study, the prevalence of increased RGC in patients taking GLP-1 agonist was 56% and the authors found that the absolute effect on RGC in patients taking GLP-1 agonists was 30% (i.e., increasing the chance of gastric contents by 30%) (11). Therefore, we propose that in the intervention group to reduce the prevalence of RGC to 25% to be clinically meaningful. Assuming Type 1 error = 0.05 and Type 2 error = 0.1 (80% power to detect this difference), then n= 36 patients will be required in each group. To accommodate for 10% participants who may withdraw from the study, we will aim to recruit n= 40 participants to each study arm, i.e. n=80 in total. Sample size calculation was verified using an online calculator (https://www.sealedenvelope.com/power/binary-superiority/)

Statistical analysis will be conducted on an intention-to-treat basis using appropriate tests for binary and continuous variables.