[Assessment and guidance of gastrointestinal function and enteral nutrition in critically ill patients using bedside ultrasound: a scoping review].

OBJECTIVE

To systematically map and synthesize the current evidence on the application of bedside ultrasound in the assessment of gastrointestinal function and the guidance of enteral nutrition in critically ill patients, and to explore its clinical value and future perspectives.

METHODS

PubMed, Web of Science, Embase, Scopus, China National Knowledge Infrastructure (CNKI), Wanfang Database, VIP Database, Chinese Medical Journals Database, and Chinese Biomedical Literature Database were searched from inception to September 4, 2025 for studies on bedside gastrointestinal ultrasound. After removing duplicate literature using EndNote X9 software and the Rayyan online literature screening platform, the articles were independently screened and cross-checked by two researchers. The following data were independently extracted by two researchers: years, country, study type, study population and sample size, grouping criteria and inter-group comparison factors, assessment protocol, ultrasound scanning protocol and results, and outcome indicators. The Newcastle-Ottawa Scale (NOS) was used to evaluate the methodological quality of included case-control studies and cohort studies, and the Cochrane Risk of Bias tool (RoB 2) was used to evaluate the methodological quality of randomized controlled trials. Through comprehensive analysis of the included literature, the application characteristics and clinical significance of bedside ultrasound in gastrointestinal dysfunction assessment and enteral nutrition implementation in critically ill patients were analyzed. Descriptive grouping and visual methods were used to conduct a variability analysis of the included studies. The studies were categorized according to study design and ultrasound assessment methods.

RESULTS

A total of 2 023 records were retrieved, and 36 studies were finally included after deduplication and screening. Included studies were published between 2019 and 2025, and comprised 19 randomized controlled trials, 15 case-control studies, and 2 cohort studies. The quality of case-control studies and cohort studies was evaluated as relatively high overall, while bias risks in randomization process and outcome reporting were found in some randomized controlled trials, with overall moderate quality and generally acceptable risk of bias. The main ultrasound assessment protocols were identified as gastric antral cross-sectional area (CSA), gastric antral motility index (MI), superior mesenteric artery (SMA) blood flow parameters, Acute Gastrointestinal Injury Ultrasound Score (AGIUS), Gastrointestinal and Urinary Tract Sonography (GUTS) score, and combined protocols. By comprehensive analysis of included studies, gastric antral CSA was found to accurately reflect gastric emptying and feeding tolerance, and high feasibility was demonstrated in predicting feeding intolerance and feeding achievement rate; gastric antral motility could be quantified by gastric antral MI, but its clinical application was limited by complex operation and fluid management. Intestinal structure and function could be objectively evaluated by AGIUS and GUTS scores, and high sensitivity and specificity in predicting 28-day mortality were demonstrated by AGIUS score≥2. Gastrointestinal structure, motility, and perfusion status could be comprehensively reflected by the gastric antral CSA combined with intestinal ultrasound protocol, and the diagnostic accuracy of acute gastrointestinal injury (AGI) and the success rate of enteral nutrition were improved.

CONCLUSIONS

As a noninvasive and repeatable assessment tool, bedside ultrasound provides valuable support for gastrointestinal monitoring and nutritional management in critically ill patients. However, the current body of evidence still has issues such as inconsistency in parameter selection, lack of standardization in measurement methods, and variability in operational procedures. Future multicenter, large-scale studies are warranted to establish unified assessment frameworks and enable precise and dynamic gastrointestinal management.