Prognostic value of central venous oxygen saturation and blood lactate levels measured simultaneously in the same patients with severe systemic inflammatory response syndrome and severe sepsis

Background: Blood lactate levels and central venous oxygen saturation (ScvO₂) are known to be useful indicators of global tissue hypoxia. However, it is unclear whether ScvO₂ correlates with lactate levels when measured simultaneously and whether changes in ScvO₂ or lactate levels in serial measurements have prognostic value. We investigated the correlation between ScvO₂ and lactate levels measured simultaneously and their association with clinical outcomes. Methods: We performed a prospective observational study of patients with severe systemic inflammatory response syndrome (SIRS) and severe sepsis who were admitted to the medical intensive care unit. ScvO₂ and lactate levels were measured simultaneously at the time of study enrollment, every 6 h for 24 h, and then every 24 h until the goal was reached. Results: Twenty-five patients were enrolled in the study; 13 have died and 12 have survived. There was no correlation between lactate levels and ScvO₂. Neither lactate levels nor ScvO₂ at the time of admission differed between nonsurvivors and survivors. Normalization of lactate levels within 48 h was significantly associated with survival. Conclusions: In patients with severe SIRS and severe sepsis, simultaneously measured ScvO₂ and lactate levels showed no correlation, and normalization of lactate levels within 48 h was a predictive factor for survival.