Obesity may present challenges during gastric ultrasound

We read with interest the article by Nersessian et al., which speculates on the relationship between residual gastric content and peri-operative semaglutide use [1].

As noted by the authors, one mechanism of action of GLP-1 receptor agonists is the delay in gastric emptying. Patients using GLP-1 receptor agonists face a risk of aspiration during the peri-operative period [2]. Nersessian et al. stated that exclusion criteria were patients with a BMI > 40 kg.m^-2 and ASA physical status of 3 and above. However, the data in table 1 show that the upper range limit of BMI is 46.4 kg.m^-2 in the semaglutide group and 40.1 kg.m^-2 in the control group. This may complicate the results. As per the ASA criteria, patients with a BMI > 40 kg.m^-2 are classified as being morbidly obese and are rated as ASA physical status 3 [3].

Using gastric ultrasound to assess gastric emptying is potentially challenging in patients with morbid obesity, for example, it can lead to significantly different baseline and average gastric volume measurements, which may create technical difficulties for the ultrasonographer [4]. The potential for an unbalanced distribution of morbidly obese patients among the study cohort groups may have impacted the study results.

Based on the above, it may be more suitable to state the number of patients with morbid obesity. It would be more appropriate to report the number and distribution of these patients in groups to demonstrate a statistically insignificant difference.