Preoperative assessment of gastric contents and volume using bedside ultrasound in adult patients: A prospective, observational, correlation study.

Background and Aims: Pulmonary aspiration of gastric contents is a serious complication of anaesthesia. The aim of this study was to determine, with the help of ultrasound, the gastric volume and content in fasted patients presenting for elective surgeries and correlate the results with fasting times and co-morbidities of the patients.

Methods: The study was conducted in 100 adult patients presenting for elective surgery. A preoperative bedside gastric ultrasound scan was done in supine and right lateral position. Gastric contents were noted, and gastric volume was calculated at the level of the gastric antrum. Gastric volume was estimated by measuring antral cross-sectional area (CSA) and using a mathematical model. Gastric volume in the right lateral decubitus (RLD) position was taken as the final reading. Analysis of variance and Student's t -test were done for statistical significance and P < 0.05 was considered statistically significant.

Results: Six out of 100 patients had solid gastric contents and 16 had >1.5 ml/kg clear liquids, although they had been fasting between 10 and 15 hours. Patients suffering from diabetes and chronic kidney disease had statistically significant increase in CSA in both supine and RLD. We also found increase in estimated gastric volume as the BMI of the patients increased.

Conclusion: Our study showed that fasting for more than 6-10 hours does not guarantee an empty stomach. Those with co-morbidities like diabetes mellitus, obesity and chronic kidney disease (CKD) appear more prone to have unsafe gastric contents.