Severe Sepsis and Septic Shock

To the Editor: We would like to address two potentially confusing issues concerning venous oxygen saturation (Svo(2)) as presented in Table 1 of the review by Angus and van der Poll (Aug. 29 issue).(1) First, Table 1 suggests that Svo(2) is raised in sepsis, severe sepsis, and septic shock. Depending on the timing of patient presentation and the type of sepsis and septic shock, Svo(2) may indeed be elevated as a result of microcirculatory shunting or mitochondrial dysfunction. However, in septic shock, Svo(2) can be depressed, reflecting an increase in the extraction of oxygen due