Hypovolemic shock characterized by:

• Hypotension: systolic blood pressure < 90 mm Hg or a drop of > 40 mm Hg from baseline or mean arterial pressure < 70 mm Hg persisting despite adequate fluid resuscitation.
• Rapid loss of significant amount of blood
• Lactate levels ≥ 2 mmol/L

State of inadequate circulation of blood because of ventricular failure due to acute cardiac conditions, concomitant presence of:

• Hypotension: systolic blood pressure < 90 mm Hg or a drop of > 40 mm Hg from baseline or mean arterial pressure < 70 mm Hg persisting despite adequate fluid resuscitation.
• Need for a continuous infusion of inotropic drugs
• Cardiac Index <2.2 L/min/m2 or use of inotropic drugs (dobutamine/isoprenaline/phosphodiesterase inhibitors or levosimendan)
• Signs of reduced heart function
• Cardiac overload or altered left/right ventricular function

Septic shock is defined as sepsis-induced hypotension, defined as systolic blood pressure < 90 mm Hg or a drop of > 40 mm Hg from baseline or mean arterial pressure < 70 mm Hg persisting despite adequate fluid resuscitation.

Only community medical acquired sepsis with a sepsis onset within 48 hours from hospital admission (i.e. different from nosocomial infection).

Lactate levels ≥ 2mmol/L.

The control group will consist on:

1. 5 healthy blood donors: serving only for the purposes of obtaining reference values for proteomics analysis
2. a cohort of 20 patients hospitalized for sepsis OR cardiac syndromes not developing shock: will be recruited from patients admitted to the hospital during the study period. The clinical status of the patients will be assessed during hospitalization to ascertain shock and AHF development. Shock development will be an exclusion criteria.

The clinical endpoint will be Acute Heart Failure (AHF), assessed by a pool of measures/estimates of cardiac function and filling pressures, based on cardiac output monitoring, inotropic drugs requirements, left and right ventricles assessment using echocardiography.

The molecular biomarkers changes will be evaluated by means of proteomics, transcriptomics and metabolomics analysis of blood samples collected at the ICU admission and within 48hr after admission.

The clinical endpoints will be:

1. The Acute Heart Failure (AHF) assessed by a pool of measures/estimates of cardiac function and filling pressures, based on cardiac output monitoring, inotropic drugs requirements, left and right ventricles assessment using echocardiography. AHF will be at evaluated within 7 days after ICU admission.
2. Mechanical ventilation (MV)-free days or organ support (vasopressor, continuous renal replacement therapy (CRRT), etc.) free-days
3. Survival to ICU
4. Prognosis at discharge from the ICU (objective - dead or alive, morbidities - and subjective)
5. Prognosis at discharge from the hospital (objective - dead or alive, morbidities - and subjective).

The changes in molecular biomarkers will be evaluated by means of proteomics, transcriptomics and metabolomics analysis of blood samples collected within 7 days after ICU admission

Patients discharged after a shock episode have high morbidity and mortality rates, and evidences indicate that physiological condition is restored only after several months. The blood sample will be collected only in patients in healthy conditions, reporting no re-hospitalization associated to shock sequelae during the follow up.