Background: Dynamic preload indices have shown better predictive value thanstatic indices. One of these dynamic indices is (manually calculated pulse pressurevariation). In this study, we tested the predictive value of stroke volume variationderived from pulse contour analysis measured by Vigileo /Flo-Trac system incomparison to pulse pressure variation.Methods: Twenty five patients with acute circulatory failure under completevolume control passive ventilation were given 500 ml Hes- steril. Trans-thoracicDoppler echocardiography was used to measure cardiac output before and afterfluid bolus and to divide patients into responders and non responders. Patients whohad an increase in cardiac index ≥ 15% were considered responders.Results: Baseline stroke volume variation ≥ 8.15% was able to predict fluidresponders with a sensitivity 100% and specificity 81.8%. Baseline pulse pressurevariation ≥ 10.2% predicted responders with a sensitivity 92.9% and specificity90.9%. No significant difference was detected between both groups regarding otherhemodynamic variables.Conclusion : Stroke volume variation is able to predict fluid responders with agood sensitivity and specificity.