In general a monitor cannot influence outcome without an associated treatment protocol to guide treatment. We will therefore study the clinical efficacy of repeated blood lactate measurements in combination with a predefined treatment protocol (aimed at resolving tissue hypoxia) during the first hours of intensive care treatment. This pragmatic approach and also the early timing of the intervention are supported by the study of Rivers et al., in which optimizing the balance between oxygen delivery and demand early in the treatment of patients with severe sepsis and septic shock resulted in a 16% absolute mortality reduction.