EDN1 and Sepsis: Several biomarkers have been related to disease severity and outcome in LRTI and sepsis, including levels of the cardiac hormone atrial-natriuretic peptide (ANP) [13-17], the stress- and volume-dependent antidiuretic hormone (ADH, vasopressin) [21-25], the endothelium derived hormones endothelin-1 (ET-1) [11,18-20] and adrenomedullin (ADM) [8-12], and procalcitonin (PCT) a specific marker of bacterial infections [26-35].