Comparative Study between Blood Lactate Level and Central Venous Oxygen Saturation as a Goal for Resuscitation in Patients with Severe Sepsis and Septic Shock

Abstract

Severe sepsis and septic shock are a leading cause of death in the world. The rate of severe sepsis hospitalizations has doubled during the last decade with estimates indicating that at least 750 000 persons are affected annually in the United States. The Surviving Sepsis Campaign international consensus guidelines recommend protocol-driven treatment that uses quantitative resuscitation for emergency department patients with severe sepsis and septic shock . The optimal goals for quantitative resuscitation of sepsis remain uncertain. It is generally accepted that hemodynamic targets should include some measure of the adequacy of cardiac preload, such as central venous pressure, and perfusion pressure, such as mean arterial pressure. A more controversial issue is the method of determining tissue oxygen delivery. Citing a single-center study, the Surviving Sepsis Campaign guidelines recommend the use of central venous oxygen saturation (ScvO2) or mixed venous oxygen saturation to assess the balance of tissue oxygen delivery and consumption. However, since its publication in 2001 a substantial amount of controversy about this single-center study has been generated in the scientific community. Additionally, recently published practice surveys have indicated that the time, expertise, and specialized equipment required to measure ScvO2 collectively pose a major barrier to the implementation of protocol-driven quantitative resuscitation programs. In contrast, serum lactate potentially represents a more accessible method to assess tissue oxygen delivery. Recently, early normalization of serum lactate in the first 6 hours was associated with an improvement of outcome in severe sepsis and septic shock patients and was proposed to guide treatment. To address the potential utility of serum lactate as a substitute for ScvO2, we conducted our study among patients presenting to the ICU with severe sepsis and septic shock. The results of this observational study conducted over 63 patients divided into survival and non survival groups indicate that there is no difference in survival between achieving the central venous oxygen saturation versus serum lactate endpoints during goal directed therapy of patients with severe sepsis and septic shock in the ICU. Our study indicates that mortality rate among lactate responders is 15/45 (33.3%) and survival rate among lactate non responders is 0%, which demonstrates a statistically significant association between early normalization of lactate level in the first 6 hours and the surviving severe sepsis and septic shock, with (p value <0.001), the analysis of the data also shows mortality rate among ScvO2 responders 20/50(40%) , and survival among ScvO2 non responders is 0%, which demonstrates a statistically significant association between normalization of ScvO2 and the surviving severe sepsis and septic shock, with (p value <0.001). In conclusion, during severe sepsis or septic shock, serum lactate is predictive for mortality and lactate directed therapy in the first 6 hours appeared as efficient as ScvO2 in septic patients.