“Pseudo-Spleen Sign” on Gastric Ultrasound in the Supine Position: A Case Report of a Patient With Delayed Gastric Emptying

Gastric ultrasound (GUS) plays a key role in identifying delayed gastric emptying and preventing pulmonary aspiration. Conventional GUS estimates gastric volume by measuring the cross-sectional area (CSA) of the antrum in the right lateral decubitus (RLD) position, which is often impractical in respiratory-unstable patients. We report an adult patient in whom GUS in the supine position successfully identified a distended gastric fundus filled with enteral nutrition (EN). In this patient, GUS in the RLD position was not feasible due to a respiratory condition. However, a daily supine abdominal ultrasound using the left upper quadrant (LUQ) view revealed a distended gastric fundus with EN. This finding suggested delayed gastric emptying; thus, we reduced the continuous EN infusion rate. This adjustment, in combination with prokinetic agents and continued clinical monitoring, may have contributed to preventing reflux and aspiration. The ultrasound appearance of the fundus resembled a spleen, and we termed it "pseudo-spleen sign." This supine GUS approach with this novel finding may offer a practical adjunct to conventional GUS that requires the RLD position.