In addition to the pragmatism of this therapeutic approach, the optimal tools with which to evaluate attainment of physiological goals have also been subject to debate. Although ScvO 2 is a valuable parameter when it is abnormal, it may be in the normal range even in severely septic patients [73] . The hemodynamic presentation, of which there are many, depends on comorbidities and stage of sepsis [83] . In addition to ScvO 2 , central venous pressure may also provide useful information. A low central venous pressure indicates hypovolemia, and a high central nervous pressure with a low ScvO 2 indicates myocardial suppression or mismatch of supply and demand. In any clinical situation, the findings must be interpreted alongside other clinical data. Other indicators may help, and systolic volume and pulse pressure variation of 10% or above also provide valuable information regarding blood volume [84] . Relatively liberal use of packed red cells to improve ScvO 2 may be offset by its potential harm [46, 47] but in the setting of severe sepsis and septic shock the theoretical risks appear balanced by the benefits in terms of tissue oxygenation [85] . Although use of central venous pressure and ScvO 2 to evaluate attainment of physiologic goals can be debated [73] , it is clear that defining reasonable goals to treat sepsis is important whatever the local organization and the available means to achieve those objectives are [86] .