This article in our series on point-of-care ultrasound (US) for the regional anesthesiologist and pain management specialist describes the emerging role of gastric ultrasonography. Although gastric US is a relatively new point-of-care US application in the perioperative setting, its relevance for the regional anesthesiologist and pain specialist is significant as our clinical practice often involves providing deep sedation without a secured airway. Given that pulmonary aspiration is a well-known cause of perioperative morbidity and mortality, the ability to evaluate for NPO (nil per os) status and risk stratify patients scheduled for anesthesia is a powerful skill set. Gastric US can provide valuable insight into the nature and volume of gastric content before performing a block with sedation or inducing anesthesia for an urgent or emergent procedure where NPO status is unknown. Patients with comorbidities that delay gastric emptying, such as diabetic gastroparesis, neuromuscular disorders, morbid obesity, and advanced hepatic or renal disease, may potentially benefit from additional assessment via gastric US before an elective procedure. Although gastric US should not replace strict adherence to current fasting guidelines or be used routinely in situations when clinical risk is clearly high or low, it can be a useful tool to guide clinical decision making when there is uncertainty about gastric contents.
In this review, we will cover the relevant scanning technique and the desired views for gastric US. We provide a methodology for interpretation of findings and for guiding medical management for adult patients. We also summarize the current literature on specific patient populations including obstetrics, pediatrics, and severely obese subjects.