Background and AimThis study investigates the effectiveness of bedside ultrasonography in predicting blood transfusion requirements in patients with upper gastrointestinal bleeding (UGIB). It focuses on evaluating the inferior vena cava (IVC) diameter, IVC collapsibility index (CI), and stroke volume (SV) as ultrasonographic measures.MethodsA hundred adult patients enrolled in this prospective clinical study. The patients were divided into two groups (group 1: only saline administered group, group 2: saline and blood administered group). IVC diameter, IVC CI, and SV were measured at the time of admission and after treatment.ResultsAt the initial admission, group 1 exhibited an IVC CI of 20.4% and an SV of 65.0 mL, whereas group 2 displayed an IVC CI of 26.6% and an SV of 58.0 mL. Upon analyzing the relationship between the Glasgow–Blatchford score (GBS) and SV, we identified a significant negative correlation (r = −0.7350; P < 0.001). Similarly, a weak negative correlation was observed between the Rockall score (RS) and SV (r = −0.4718; P < 0.001). It is worth noting that patients with UGIB require blood transfusion if their SV falls below 62.5 mL, with an area under the curve (AUC) of 89.1% and a 95% confidence interval (CI) ranging from 82.8% to 95.4%.ConclusionIVC CI and SV can be used as parameters to predict the need for blood transfusion in the ED in patients with UGIB.