Determination of the Dissociation Constant (Ka) of Plasma and Whole Blood in Septic Patients

Group 1: Septic patients Inclusion Criteria for Group 1: * Diagnosis of Sepsis * Age \> 18 years * Informed or deferred informed consent Exclusion Criteria for Group 1: * Pregnancy * Bilirubin \> 4 mg/dL * Minor or major thalassemia * Transfusion of more than 4 Units of packed red blood cells and/or 1 L of plasma during the 24 hours prior to enrollment Group 2: Healthy volunteers Inclusion criteria for Group 2: * informed consent * Age \> 18 years Exclusion criteria for Group 2: • Pregnancy Group 3: Non-septic patients Inclusion criteria for Group 3: * Informed consent * Age \>18 years * Planned ICU admission after elective surgery Exclusion criteria for Group 3: * Diagnosis of sepsis * Pregnancy * Bilirubin \>4 mg/dL * Liver cirrhosis * Onco-hematological diseases * Minor or major thalassemia * Transfusion of more than 4 Units of packed red blood cells and/or 1 L of plasma during the 24 hours prior to enrollment