The relationship between central venous pressure, caval–aortic index and inferior vena cava diameter in sepsis

Background Rapid bedside assessment of intravascular volume status is critical during early sepsis management in the emergency department (ED) yet commonly used static parameters such as central venous pressure (CVP) and isolated inferior vena cava (IVC) measurements have limited reliability for predicting fluid responsiveness. Objectives This study aimed to evaluate the diagnostic performance of the IVC–to–aorta diameter ratio (IVC/Ao) and its dynamic change (ΔIVC/Ao) using bedside ultrasonographic measurements in septic patients. Methods In this prospective observational study, adult patients presenting to the ED with Sepsis‐3–defined sepsis were included. Manometric CVP, ultrasonographic IVC diameter, and aortic diameter were measured at baseline and 3 hours after standardized fluid resuscitation. Fluid responsiveness was defined as a ≥10% increase in mean arterial pressure. Correlation analyses and receiver operating characteristic curve analyses were performed. Results Sixty patients were included in the analysis. Baseline CVP, IVC diameter, and aortic diameter did not differ significantly between fluid responders and non‐responders. ΔIVC/Ao was significantly higher in responders ( p = 0.026). ΔIVC/Ao showed the highest discriminative performance among the evaluated parameters (the area under the curve = 0.679) with a specificity of 83%, whereas CVP and isolated ultrasonographic parameters demonstrated limited predictive ability. Conclusion Dynamic bedside ultrasonographic assessment integrating venous and arterial dimensional changes may provide clinically relevant information beyond static indices. Although ΔIVC/Ao should not be used as a standalone parameter, it may serve as a useful adjunct within multimodal hemodynamic reassessment in septic patients in the ED.