Near-infrared spectroscopy during stagnant ischemia estimates central venous oxygen saturation and mixed venous oxygen saturation discrepancy in patients with severe left heart failure and additional sepsis/septic shock

INTRODUCTION: Discrepancies of 5-24% between superior vena cava oxygen saturation (ScvO(2)) and mixed venous oxygen saturation (SvO(2)) have been reported in patients with severe heart failure. Thenar muscle tissue oxygenation (StO(2)) measured with near-infrared spectroscopy (NIRS) during arterial occlusion testing decreases slower in sepsis/septic shock patients (lower StO(2 )deoxygenation rate). The StO(2 )deoxygenation rate is influenced by dobutamine. The aim of this study was to determine the relationship between the StO(2 )deoxygenation rate and the ScvO(2)-SvO(2 )discrepancy in patients with severe left heart failure and additional sepsis/septic shock treated with or without dobutamine. METHODS: Fifty-two patients with severe left heart failure due to primary heart disease with additional severe sepsis/septic shock were included. SvO(2 )and ScvO(2 )were compared to the thenar muscle StO(2 )before and during arterial occlusion. RESULTS: SvO(2 )correlated significantly with ScvO(2 )(Pearson correlation 0.659, P = 0.001), however, Bland Altman analysis showed a clinically important difference between both variables (ScvO(2)-SvO(2 )mean 72 ± 8%, ScvO(2)-SvO(2 )difference 9.4 ± 7.5%). The ScvO(2)-SvO(2 )difference correlated with plasma lactate (Pearson correlation 0.400, P = 0.003) and the StO(2 )deoxygenation rate (Pearson correlation 0.651, P = 0.001). In the group of patients treated with dobutamine, the ScvO(2)-SvO(2 )difference correlated with plasma lactate (Pearson correlation 0.389, P = 0.011) and the StO(2 )deoxygenation rate (Pearson correlation 0.777, P = 0.0001). CONCLUSIONS: In patients with severe heart failure with additional severe sepsis/septic shock the ScvO(2)-SvO(2 )discrepancy presents a clinical problem. In these patients the skeletal muscle StO(2 )deoxygenation rate is inversely proportional to the difference between ScvO(2 )and SvO(2); dobutamine does not influence this relationship. When using ScvO(2 )as a treatment goal, the NIRS measurement may prove to be a useful non-invasive diagnostic test to uncover patients with a normal ScvO(2 )but potentially an abnormally low SvO(2). TRIAL REGISTRATION: NCT00384644 ClinicalTrials.Gov.