Blood lactate levels have long been related to tissue hypoxia, a severe condition in critically ill patients associated with the development of organ system failure and subsequent death. Increased blood lactate levels and failure to normalize blood lactate levels during treatment have been associated with increased morbidity and mortality. However, evidence of improved clinical outcome of lactate-directed therapy is limited and difference in the use of blood lactate monitoring in the intensive care unit exists between hospitals. This warrants a study on the efficacy of early blood lactate-directed therapy. In this study the efficacy of 8 hours of early lactate-directed therapy (therapy aimed at resolving tissue hypoxia that is guided by serial blood lactate levels) will be compared with 8 hours of control group therapy (without lactate measurement).