Hydrocortisone and Fludrocortisone for Critical Illness-related Corticosteroid Insufficiency

Inclusion Criteria: * Adult (≥ 18 years); * Hospitalized in an intensive care unit; * SOFA score ≥ 4, for at least 6 consecutive hours; * Informed written consent from patient or from legally authorized next of kin, or emergency deferred consent; * Affiliation to a social security system or to a universal health coverage (Couverture Maladie Universelle, CMU). Exclusion Criteria: * Any suspected or proven acute adrenal insufficiency (As defined in international guidelines; basal cortisol \< 5 μg/dL or peak (60) cortisol \<18 μg/dL) * Expected death or withdrawal of life-sustaining treatments within 48 hours * Known chronic adrenal insufficiency * Concomitant treatment that inhibits cortisol production * Septic shock (Singer Jama 2016) * Active tuberculosis or fungal infection * Active viral hepatitis or active infection with herpes viruses * Hypersensitivity or contraindication to hydrocortisone, fludrocortisone or Synacthène® or any of their excipients ( SmPC) * Patient needing either anti-inflammatory corticosteroids or substitutive hydrocortisone for any reason (Such as those suffering from COVID-19 pneumonia requiring oxygen therapy). * Current treatment by more than 15 mg/d of prednisone (or equivalent) for more than 30 days * Diabetic ketoacidosis or hyperglycemic hyperosmolar syndrome * Pregnant or breastfeeding woman * Moribund patient * Previously enrolled in this study * Participation to another interventional study that focuses on CIRCI and/or corticoid drugs and/or that addresses a similar primary endpoint as Hornbill ( ventilator- and vasopressor-free survival ) * Patient under guardianship or tutorship Note: Included patients for whom acute adrenal insufficiency would be detected in the Synacthen ® test performed as part of the research for the diagnosis of CIRCI will not be randomized since they should be treated by corticosteroids.