Microcirculatory Alteration and Biomarkers: New Approach for Early Assessment of Septic Multi-organ Dysfunction

Inclusion Criteria: Patients ≥18 years of age with severe sepsis and fulfill the following criteria at the admission to ICU: * Peritonitis (abdominal infection) and performed source control (either surgically or interventionally) * 2 or more criteria for systemic inflammatory response syndrome (temperature \>38° or\<36°; heart rate \>90 beats per minute; respiratory rate \>20 breaths per minute or paCO2 \<32 mmHg; white blood cell count \>12,000/mm3, \<4000mm3 or \>10% immature forms) and serum lactate level of 4mmol/l and more or refractory hypotension - mean arterial pressure \<65mmHg or systolic blood pressure \<90mmHg after fluid challenge of 1000ml or more /30min * Absence of any familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule * Written informed consent prior to any study procedures Exclusion Criteria: * Pre-existing renal-replacement therapy in the pre-operative course * Pre-existing shock * Acute coronary syndrome * Active hemorrhage * Trauma * Known allergy to ultrasound contrast media * Anemia with hemoglobin concentration \< 7g/dl * Patients not able to give written informed consent