Ultrasound has become quite popular in regional anesthesia, as well as to guide cannulation of central veins and peripheral veins and arteries. Ultrasound can also be used to measure preoperative gastric content. Gastric fluid volume is estimated based on a measurement of the cross-sectional area (CSA) of the antrum. Most studies have been performed in individuals who are not obese. Drs. Peter Van de Putte, Department of Anesthesiology, AZ Monica, campus Deurne, Deurne, Belgium, and Anahi Perlas, Department of Anesthesia and Pain Management, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada, and Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada, examined whether gastric antrum measurements could be performed in obese individuals (BMI ≥35 kg/m2) who fasted overnight before elective surgery. The results of their analysis are published in this month’s issue of Anesthesia & Analgesia in the article titled “Gastric Sonography in the Severely Obese Surgical Patient: A Feasibility Study.”
Sixty patients whose BMI ranged from 35 to 69 kg/m2 were enrolled in this study. Gastric ultrasonography in the right lateral decubitus position could be performed in 95% of subjects and in 90% of subjects in the supine position. The antrum was not visible in 1 subject in either position. A 3-point grading system (antral grades 0-2) has previously been developed (reference 1; and reference 2) to discriminate between low and high gastric volumes. The authors were able to calculate antral grade in 88% of patients. Of those patients, only 3 had an antral grade 2, defined as visible fluid in both supine and the right lateral decubitus positions. No patient had thick fluid or solid gastric content.
Drs. Lionel Bouvet, Inserm, LabTau, Lyon, France; Université de Lyon, Lyon, France; and Department of Anesthesia and Intensive Care, Édouard Herriot Hospital, Hospices Civils de Lyon, Lyon, France, and Dominique Chassard, Université de Lyon, Lyon, France, and Department of Anesthesia and Intensive Care, Femme Mère Enfant Hospital, Hospices Civils de Lyon, Bron, France, note in their accompanying editorial titled “Ultrasound Assessment of Gastric Content in the Obese Patient: One More Step for Patient Safety,” that this work “contributes to the validation of the preoperative ultrasonographic assessment of gastric contents status in clinical practice. Furthermore, it opens up opportunities for additional clinical research to improve the understanding in order to ultimately reduce the incidence of pulmonary aspiration of gastric contents.”