In the recent sepsis-definitions, myocardial depression is included in the definition of severe sepsis, indicated as lowered cardiac index or echocardiographically documented cardiac dysfunction. Myocardial dysfunction occurs in greater than 50% of patients with severe sepsis and septic shock. In this context, B-type natriuretic peptid (BNP) from ventricular myocytes may serve as a surrogate biomarker for the evaluation and quantification of myocardial dysfunction. Biologically active BNP is cleaved into inactive NT-proBNP, which is supposed to be a better marker of myocardial dysfunction and prognosis in patients with severe sepsis and septic shock. However, severity of illness dependent association of myocardial dysfunction, especially left ventricular diastolic function, dosage of norepinephrine, NT-proBNP and biomarker plasma concentrations has not been systematically investigated in postoperative/posttraumatic patients in septic shock or volume-deficiency/hemorrhagic shock. Moreover, data regarding NT-proBNP plasma concentrations and renal function in postoperative/posttraumatic patients are sparse. Therefore, this prospective observational study will enroll n= 200 postoperative/posttraumatic patients to monitor longitudinally NT-proBNP, biomarkers, and cell surface markers on leukocytes to find out whether there is a discriminating pattern of myocardial dysfunction, NT-proBNP and biomarkers in patients with non-septic or septic shock, respectively, and with beneficial or harmful outcome.