Values of SVV indices and CO variations. Values of SVV estimated by PiCCO before the rapid infusion and values of maximum variation of cardiac output (Δ PCCO) obtained during the second time window. The dashed horizontal line marks the threshold, which separates the responsive (R) from nonresponsive (NR) maneuvers. The dashed black vertical line marks the threshold commonly used in the literature (9.5%) for SVV index in order to predict the outcome . The green line marks the threshold obtained in the present work.