Residual gastric content and peri-operative semaglutide use assessed by gastric ultrasound

We read with interest the study by Nersessian et al., which explores the relationship between peri-operative semaglutide use and increased residual gastric content as assessed by gastric ultrasound [1]. This prospective study contributes to the emerging literature on GLP-1 receptor agonists (GLP-1 RAs) and delayed gastric emptying, raising important considerations for peri-operative management [2]. However, these findings prompt a need for greater specificity within clinical guidelines, particularly regarding the differing needs of patients using GLP-1 RAs for weight loss and to those prescribed these drugs for type 2 diabetes.

Although it is relevant that data are now available on volume of pre-operative gastric contents in patients using GLP-1 RA for weight loss, there are several methodological limitations that hinder the applicability. The study employs a small sample size without formal power calculations, using convenience sampling that undermines the statistical robustness of the findings. In addition, only a small number of baseline variables is presented, making it difficult to assess the validity of comparing the study groups. Factors such as dose of semaglutide, duration of use and the presence of gastrointestinal symptoms are missing. All can significantly influence the risk of increased pre-operative residual gastric contents [3]. Moreover, although BMI is reported, it remains unclear whether the semaglutide group represents patients with formerly higher BMIs, reduced following semaglutide treatment, being compared with a possibly healthier control group with distinct gastric function. Finally, the authors propose using gastric ultrasound as a pre-operative tool to evaluate gastric content. While valuable, the variability inherent in this subjective technique, which is also highlighted by the authors, limits its broad application.

Nersessian et al. suggest extending the pre-operative discontinuation period of GLP-1 RAs from 1 to 2–3 weeks. This recommendation, however, is not substantiated by their results, nor by the current literature. There is limited evidence supporting the efficacy of discontinuation in reducing volume of gastric content, which calls into question the proposed cessation periods for peri-operative settings. In addition, recent studies have suggested that GLP-1 RA use does not necessarily correlate with a clinically significant aspiration risk [4]. Furthermore, GLP1 RAs with even longer half-lives than semaglutide are expected, which will be challenging to discontinue promptly and may not prevent delayed gastric emptying effectively even if cessation is attempted.

In addition, prolonged discontinuation in patients with type 2 diabetes, who rely on GLP-1 RAs for glycaemic control, could risk peri-operative hyperglycaemia, which itself may contribute to delayed gastric emptying [5], further complicating peri-operative management and potentially increasing the risk of postoperative wound infection [6]. In contrast, patients on GLP-1 RAs solely for weight loss may tolerate a longer discontinuation without the same risks, supporting a more targeted approach within guidelines that consider the primary indication for GLP-1 RA use.

In conclusion, while the study by Nersessian et al. underscores the need for cautious use of GLP-1 RAs peri-operatively, it is important to distinguish between GLP-1 RA use for weight loss and for glycaemic control in future guidelines. While a longer cessation period may be feasible for patients using these drugs for weight loss, patients with type 2 diabetes require careful consideration of the potential for hyperglycaemia. In addition, the effectiveness of different cessation periods of GLP1 RAs on gastric emptying has not been studied adequately. The evidence required to support withholding GLP-1 RAs are trials comparing pre-operative cessation vs. continuation of GLP-1 RAs. Such research should evaluate the volume of residual gastric content and quality of glycaemic control in patients with and without type 2 diabetes.