Point-of-Care Ultrasound in the Assessment of Gastric Residual Volume: A Protocol of Scoping Review (Preprint)

BACKGROUND Pulmonary aspiration of gastric contents is a serious clinical complication, especially in patients receiving enteral nutrition or undergoing anesthesia. Gastric residual volume (GRV) is a commonly used surrogate marker to identify delayed gastric emptying and enteral nutrition intolerance, which may increase aspiration risk. Traditional GRV measurement methods are invasive and lack standardization. Point-of-care ultrasound (PoCUS) has emerged as a promising, non-invasive, and bedside alternative. Despite its growing clinical use, there is no consolidated guidance on PoCUS procedures for GRV assessment in adult patients. OBJECTIVE This scoping review aims to map and synthesize the available evidence on procedural techniques, interpretation criteria, and decision-making applications related to PoCUS for GRV assessment. METHODS This scoping review will follow the JBI Collaboration methodology and will be reported in accordance with PRISMA-ScR guidelines. The PCC mnemonic (Population, Concept, Context) guided the formulation of the research question. Systematic searches will be performed in MEDLINE, CINAHL, Embase, Scopus, Cochrane, and LILACS, along with grey literature sources. Eligible studies will include primary studies, reviews, and clinical guidelines focused on PoCUS for GRV assessment in adults (≥18 years). Two independent reviewers will conduct screening and data extraction. The synthesis will be structured using the I-AIM framework (Indication, Acquisition, Interpretation, Medical decision-making). Results will be summarized narratively, in tables, and through visual representations such as flowcharts and conceptual diagrams. RESULTS A descriptive synthesis will be structured using the I-AIM framework (Indication, Acquisition, Interpretation, and decision-making). Quantitative data will be presented in tables, while qualitative findings will be analyzed thematically. Narrative, tabular, and visual formats—including diagrams, flowcharts, and summary figures—will be used to highlight variations, patterns, and gaps in practice. CONCLUSIONS This review will identify and categorize the procedures, technical parameters, and clinical applications of PoCUS for GRV assessment in adult patients. By mapping existing evidence, the findings will contribute to future research, educational curricula, and the development of clinical guidelines for nurses. Additionally, the review will highlight methodological gaps and practice variations that may impact the safe and effective use of PoCUS in diverse healthcare settings. CLINICALTRIAL This protocol has been registered in the Open Science Framework (OSF): https://osf.io/cq8s3