Septic shock is the most severe form of infection. Currently, an early specific biomarker for septic shock is needed. Remember that shock situations are numerous, not only septic (eg hemorrhagic, cardiogenic...), and also accompanied by a severe pro-inflammatory state that it is sometimes difficult to distinguish from a septic state. Procalcitonin (PCT) is the most studied biomarker but still lacks sensitivity (77%) and specificity (79%). The investigators hypothesize that the Vasn could become this potential new biomarker and would allow a better diagnosis and thus the need or not to treat patients with antibiotics. The laboratory studies suggest a link between Vasn and septic shock. The goal of this project is to measure and compare plasma Vasn concentrations in 2 groups of patients = group 1: septic shock versus group 2: non-septic shock. Briefly, shock is defined as low blood pressure requiring vasopressor agents with confirmed infection (group 1) or without suspected infection such as patients admitted in intensive care unit post cardiac surgery with CBP (group 2). The investigators will also assess patient 28-day mortality to identify Vasn as a potential prognostic biomarker.

Inclusion Criteria:

• Adults over 18 years.
• Patients admitted for less than 24 hours in intensive care unit of the CHU Amiens Picardie.
• Group 1: patients with septic shock defined by sepsis with 2 mmol/l Lactates, requiring vasopressors to maintain mean blood pressure at 65 mmHg (despite adequate vascular filling) in the presence of fever (T°>38.3) with a documented or suspected infection
• Group 2: patients with a shock defined by arterial hypotension requiring the use of vasopressors with 2 mmol/l Lactates but without suspected infection and apyrexie (T°<38°). For example: vasoplegia post cardiac surgery with CBP or cardiogenic shock or hemorrhagic shock

Exclusion Criteria:

• Pregnant women
• Group 1 : No evidence of suspected or documented infection
• Group 2 : Presence of fever and/or suspected infection