Assessment of Peripheral Perfusion in the Critically Ill Patient

Septic patient: Inclusion criteria: * ICU admission with septic shock defined as: * documented infection (suspected or confirmed) AND * systemic mean blood pressure \<65mmHg requiring any dose of vasopressor despite adequate fluid resuscitation (min. 20ml/kg crystalloids) AND * lactate \>2mmol/l * Deferred consent by a relative with following informed consent by patient as documented by signatures (Appendix Informed Consent Form) Exclusion criteria: * Age \<18 or \>80 years * present or suspected myocardial ischemia * acute pulmonary embolism * known liver disease - Child-Pugh -Class B or C * known chronic renal failure * known peripheral artery disease Patient after cardiac surgery: Inclusion criteria: * ICU admission after coronary artery bypass grafting or valve surgery with cardiopulmonary bypass * General consent with admission at the University hospital Exclusion criteria: * Age \<18 or \>80 years * known peripheral artery disease * no or only low dose of vasopressors (\<300µg/h) at ICU admission * present or suspected myocardial ischemia * acute pulmonary embolism * known liver disease - Child-Pugh -Class B or C * known chronic renal failure Healthy volunteers: Inclusion criteria: \- Informed consent as documented by signature (Appendix Informed Consent Form) Exclusion criteria: * Age \<18 or \>80 years * known peripheral artery disease