IL6 and capillary leak syndrome: To account for CLS pathophysiology, we proposed several factors to be included into our scoring system: A marker for edema (i.e., echogenicity measurement by ultrasound), microvascular malperfusion (serum-lactate), underlying inflammation (IL-6), endothelial biomarkers (angiopoietin-2, ICAM-1, syndecan-1) and the disease severity (SOFA-Score) were, therefore, combined to create a novel score (the “CLS-Score”).