外傷における超音波検査（FAST）の診断的および予後的価値：出血の層別化と外傷重症度分類における

Uncontrolled hemorrhage is the leading preventable cause of early death after trauma. The Focused Assessment with Sonography in Trauma (FAST) examination is widely used to detect free intraperitoneal fluid, but its prognostic value for hemorrhage grading and trauma severity classification requires synthesis. A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. PubMed, Embase, Scopus, and Cochrane databases were searched through March 2025 for human studies assessing the diagnostic accuracy and prognostic utility of FAST in blunt or penetrating trauma. Studies were selected based on the population (or patient/problem), intervention, comparison (or control), and outcome (PICO) framework, excluding case reports, editorials, conference abstracts, animal studies, and those without extractable outcomes. Risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) and the Quality Assessment of Diagnostic Accuracy Studies, Version 2 (QUADAS-2) tool. Seven studies, including approximately 7,310 patients, met the inclusion criteria. FAST demonstrated high specificity up to 97% for detecting clinically significant hemoperitoneum. Positive findings were associated with increased transfusion requirements, greater need for surgery or embolization, higher intensive care unit (ICU) admissions, elevated injury severity, and higher short-term mortality. Semi-quantitative interpretations, such as the number and distribution of positive zones, enhanced hemorrhage stratification. Combining FAST with physiological parameters in validated trauma scoring systems improved the prediction of massive transfusion and operative urgency. Despite operator dependence and limited sensitivity for small or retroperitoneal bleeds, standardized protocols and serial assessments can strengthen its role in early trauma decision-making.