Should We Abandon Measuring SvO2 or ScvO2 in Patients with Sepsis?
The mixed venous oxygen saturation (SvO2) has been used to assess the adequacy of oxygen delivery (DO2) to oxygen consumption (VO2). Since central venous catheters (CVCs) are now more often inserted than pulmonary artery catheters (PAC) in critically ill patients, central venous oxygen saturation (ScvO2) has been proposed as a substitute for SvO2. In 2001, Rivers et al. proposed a step-by-step strategy called early goal-directed therapy (EGDT) that aimed at normalizing the ScvO2 within the first 6 h of resuscitation of patients with severe sepsis or septic shock . A single-center randomized controlled trial (RCT) showed that application of EGDT significantly decreased mortality in comparison with a control group, in which ScvO2 was not used . Following the publication by Rivers et al. , EGDT was endorsed by the Surviving Sepsis Campaign (SSC) in 2004 . More recently, three multicenter RCTs (ProCESS , ARISE  and ProMISe ) compared EGDT (using ScvO2) to standard care (with no use of ScvO2). In none of these trials did EGDT show any benefit in terms of outcome, as confirmed by a meta-analysis . Differences between the trials (design/study population/management of the control group/general management of patients with sepsis) may have contributed to the divergent results of these trials . Nevertheless, the SSC experts removed ScvO2 (and SvO2) from the recommendations of the most recent version of the SSC guidelines . While targeting specific predefined values in all patients may be questioned, it is probably unwise to neglect the potential interest of measuring SvO2/ScvO2 in patients with sepsis. In this chapter, we discuss why there is still a place for the measurement of SvO2 or ScvO2 in patients with sepsis.