Obesity may present challenges but does not preclude gastric ultrasound

Abstract

We thank Yarımoglu et al. [1] for their valuable comments regarding our recently published work [2]. As noted in our methods, we had initially not included patients with BMI > 40 kg.m^-2 and ASA physical status score ≥ 3 [2]. However, and as rightfully pointed out by Yarımoglu et al. [1], the data in table 1 indicate that the upper range limit of BMI was 46.4 kg.m^-2 in the semaglutide group and 40.1 kg.m^-2 in the non-semaglutide group [2]. Upon reviewing our data, we identified four patients with morbid obesity (BMI 40.7, 42.4, 45.1 and 46.4 kg.m^-2) in the semaglutide group and one (BMI 40.1 kg.m^-2) in the non-semaglutide group [2]. While we apologise for this oversight, on further review of our data, neither of these patients had increased residual gastric content upon point-of-care gastric ultrasound assessment.

As per our institutional protocol, all patients (regardless of BMI) who had used semaglutide within 10 days of their elective surgical procedure underwent pre-operative bedside gastric ultrasound to mitigate the risk of bronchoaspiration which explains the inclusion of patients with morbid obesity in our dataset. In the non-semaglutide group, patients were recruited from a convenience sample of those presenting for elective procedures under anaesthesia, according to the institutional elective surgical scheduling. Given logistical constraints, it was impractical to perform gastric ultrasound in all patients during the data collection period.

Importantly, despite our unintentional inclusion (in both groups) of five patients with BMI > 40 kg.m^-2, the conclusions of our study remain unchanged [2]. Even with the original analysis using propensity score, no statistical difference in residual gastric content was observed related to obesity, which aligns with existing published data [3]. Our findings suggest that semaglutide use and patient age (but not BMI) were the key determinants of increased residual gastric content in our studied population. It is important to note that our studied groups were not initially matched for age, weight, BMI or sex, as the convenience sampling of non-semaglutide users remains a recognised limitation [2].

Finally, our primary reason for excluding patients with BMI > 40 kg.m^-2 was the potential technical challenges in performing gastric ultrasound in this patient population, which could lead to inconclusive results. Nevertheless, several studies have shown the feasibility and validity of point-of-care gastric ultrasound to assess residual gastric content in patients with BMI > 40 kg.m^-2 [4, 5]. It is important to note that all bedside gastric ultrasound assessments in our study were performed by trained/experienced professionals, thereby significantly reducing, albeit not eliminating, the potential for interpretation bias.