Sepsis-induced coagulopathy is associated with impaired tissue oxygen extraction and microvascular reactivity: a prospective observational study

BACKGROUND: Coagulopathy is a key driver of organ dysfunction during sepsis/septic shock, yet its relationship with microcirculatory autoregulation is not fully characterized. This study aimed to evaluate the association between sepsis-induced coagulopathy (SIC) and alterations in tissue oxygenation, oxygen extraction capacity and microvascular reactivity. METHODS: Prospective observational study on 23 adult septic patients. Coagulation status was evaluated with standard laboratory parameters and thromboelastography (TEG). A SIC score ≥ 4 was used to identify the presence of coagulopathy. The peripheral (skeletal muscle) tissue oxygen saturation (StO2) was assessed using thenar near infrared spectroscopy (NIRS). By combining a vascular occlusion test, the desaturation rate during ischemia was assessed as an index of oxygen extraction capacity: this was measured separately for the first (StO2 downslope-1) and last part (StO2 downslope-2) of the desaturation curve, and the difference between the two was calculated (delta-downslope). The reoxygenation rate (StO2 upslope) and the area of the hyperemic phase were calculated to evaluate microvascular reactivity. RESULTS: In patients with SIC, the delta-downslope was higher (1.7 ± 2.5 versus -0.8 ± 3.2, p = 0.049) and the StO2 upslope was reduced (96 ± 74 versus 185 ± 91, p = 0.017), suggesting altered tissue oxygen extraction capacity and microvascular reactivity. Both parameters were able to discriminate the presence of SIC in the receiver operating characteristics curve analysis. Negative correlations were found between StO2 downslope-1 and TEG maximum amplitude (r = -0.470, p = 0.023), and Delta-Downslope and platelet count (r = -0.527, p = 0.01). CONCLUSIONS: SIC is associated with alterations in peripheral tissue oxygen extraction capacity and microvascular reactivity.