Gastrointestinal point-of-care ultrasound for enteral nutrition management in critically ill adults: a scoping review

Abstract

Background Gastrointestinal point-of-care ultrasound has been investigated as a non-invasive, bedside adjunct for gastrointestinal assessment and enteral-feeding decision-making in critical care; however, existing protocols and their outcome reporting remain fragmented. This scoping review mapped the existing evidence landscape on the use of gastrointestinal point-of-care ultrasound in the management of enteral nutrition in critically ill adults. Methods Comprehensive searches in 10 databases (PubMed, EMBASE, Web of Science, Cochrane, CINAHL, Scopus, China National Knowledge Infrastructure, Wanfang, VIP, China Biological Medicine Literature Database) identified 5,123 records. Studies focusing on ultrasound-assessed gastrointestinal function to guide enteral nutrition, or to predict enteral nutrition intolerance and clinical prognosis, were screened, summarized, and descriptively analyzed. Results 49 unique studies were identified, including 36 interventional and 13 observational studies. Geographically, the synthesized evidence was heavily concentrated in China. Ultrasound indicators for gastrointestinal function included the gastric antrum (gastric residual volume, motility index, cross-sectional area), colon (colon diameter and peristaltic frequency), small intestine (small intestine diameter, wall thickness, peristalsis), and superior mesenteric artery hemodynamics. Observational studies showed Area Under the Curve point estimates frequently around or above 0.70, with substantial heterogeneity and no independent external validation reported for enteral nutrition intolerance and mortality. Among interventional studies, time to achieve feeding goals and intensive care unit length of stay were the most frequently evaluated outcomes (27/36), whereas in-hospital mortality was evaluated in only 8 of 36 studies; outcome reporting was heterogeneous and is presented descriptively. Conclusion The synthesized literature suggests the potential utility of gastrointestinal point-of-care ultrasound as an objective, non-invasive bedside tool for gastrointestinal assessment and feeding protocol modulation. However, because no formal critical appraisal or pooled comparative or diagnostic analysis was performed, this review cannot establish clinical effectiveness, universal thresholds, or patient-important benefit. Future research priorities include consensus definitions and acquisition standards, effect estimates with confidence intervals and patient-important outcomes, inter-operator reliability and training evaluation, and external validation across diverse health systems.