Evaluation of the Caval-Aortic Index During Early Fluid Resuscitation in Patients With Acute Pancreatitis.

BACKGROUND Early fluid resuscitation is a cornerstone of acute pancreatitis management; however, bedside assessment of the early hemodynamic response remains challenging. We prospectively evaluated serial ultrasonographic parameters and peripheral venous pressure (PVP) during initial fluid resuscitation in patients with acute pancreatitis. MATERIAL AND METHODS Patients with confirmed acute pancreatitis underwent serial measurements of inferior vena cava (IVC) diameter, aortic diameter, caval-aortic (IVC/Ao) index, PVP, and mean arterial pressure (MAP) before and 2 hours after fluid resuscitation. Early hemodynamic response was defined as an increase of at least 10% in MAP from baseline. Correlation and receiver operating characteristic (ROC) analyses with DeLong's test were performed. RESULTS Sixty patients were included. After fluid resuscitation, IVC diameter, IVC/Ao index, PVP, and MAP significantly increased, whereas aortic diameter remained unchanged. Changes in IVC diameter (ΔIVC) were positively correlated with changes in MAP (ΔMAP); changes in aortic diameter (ΔAorta) showed a significant inverse correlation. The ΔIVC/Ao index showed a similar positive trend, but this correlation was not statistically significant. ΔAorta demonstrated the highest discriminatory performance for identifying MAP-defined early hemodynamic response (area under the curve, 0.680; 95% confidence interval, 0.535-0.824), although pairwise ROC analysis revealed no significant superiority over the other ultrasonographic parameters. CONCLUSIONS Serial ultrasonographic assessment may provide clinically relevant information during early fluid resuscitation in acute pancreatitis. No ultrasonographic parameter demonstrated clear superiority. ΔAorta showed the numerically highest, although modest, discriminatory performance in this cohort. These findings should be considered hypothesis-generating and warrant further investigation before any comparative advantage of arterial ultrasonographic assessment can be inferred.