Initial Low Oxygen Extraction Ratio Is Related to Severe Organ Dysfunction and High In-Hospital Mortality in Severe Sepsis and Septic Shock Patients

Abstract

BackgroundIn severe sepsis and septic shock, global tissue hypoxia is a key development preceding multi-organ failure and death. ObjectiveOur aim was to find whether the initial low oxygen extraction ratio (OER) is related to the severity of organ dysfunction and to predict the in-hospital mortality in severe sepsis or septic shock patients. MethodsThis was a secondary analysis of 169 patients with severe sepsis or septic shock in an emergency department. We calculated OER with 1- central venous oxygen saturation (ScvO2)/arterial oxygen saturation and compared the data according to the level of OER (high > 0.3, 0.2 ≤ normal ≤ 0.3, lower < 0.2). ResultsA total 133 patients were selected for analysis. OER was inversely proportional to ScvO2 (r2 = 0.878; p < 0.001). The sepsis-related organ failure assessment score and in-hospital mortality of each group were 6.2 ± 3.7 and 37.0% for high OER, 5.7 ± 3.0 and 11.8% for normal OER, and 7.7 ± 3.9 and 41.7% for low OER, respectively (p = 0.034; p = 0.003). In patients with initial ScvO2 of >70%, in-hospital mortality of patients with low OER was significantly higher than patients with normal OER. ConclusionsInitial low OER was associated with severe organ dysfunction that resulted in high mortality with severe sepsis and septic shock. When patients had initial ScvO2 of > 70% but abnormally low OER, their in-hospital mortality was higher than in normal OER patients. Therefore, the OER should be considered when attempting to predict the outcome of septic patients using ScvO2 at an early stage of management for sepsis.