The purpose of this study is to observe the variation of Hemodynamics、lactic acid、base excess、peripheral vascular resistance and DO2 through FloTrac™/Vigileo™ system after rapid infusion mannitol in neurosurgery.The hemodynamic changes after mannitol infusion are shown in Figure 1. HR (Fig. 1A) and systolic BP (Figure 1B) significantly increased between 0 min and 10 min (P = 0.041) and between -10 min and 10 min (P = 0.073), respectively; these two variables decreased steadily and returned to the baseline. Diastolic BP (Fig. 1B) showed no significant change after mannitol infusion (P = 0.102). CVP (Fig. 1C) significantly increased between -20 min and 0 min (P < 0.001) and constantly decreased after 0 min, which remained below the baseline between 30 min and 60 min. CI (Fig. 1D) and SVI (Fig. 1E) showed a significant persistent increase between -20 min to 0 min (P < 0.001) and between -20 min and 10 min (P < 0.001), respectively. SVV exhibited a dipper-type change shown as a significant decrease between -20 min and 0 min and a significant increase between 0 min and 60 min (P < 0.001), which returned to the baseline after 20 min.