Synopsis: Sepsis is a highly lethal condition with mortality ranging from 30-45%. Previous randomized trials on the use of hydrocortisone in patients with septic shock showed conflicting effects on mortality, despite both demonstrating an earlier a reversal of shock. The Adjunctive Corticosteroid Treatment in Critically Ill Patients with Septic Shock (ADRENAL) study was designed to further address this contentious topic. Patients enrolled in the ADRENAL study were adults >18 years old, on mechanical ventilation with strong or confirmed evidence of infection, at least two systemic inflammatory response syndrome (SIRS) criteria, and who were currently being treated with vasoactive medications for at least four hours. Patients were excluded if they were likely to receive treatment with systemic glucocorticoids for another indication, had received Etomidate during the current admission, or if they were deemed likely to die from a pre-existing co-morbid disease within 90 days after randomization. A total of 3658 patients (from 5501 eligible patients screened) were enrolled from 69 medical-surgical ICUS in five countries. A total of 1826 were randomized to the placebo group and 1832 were randomized to the hydrocortisone group. The hydrocortisone group received a continuous infusion of 200mg IV hydrocortisone per day for a maximum of 7 days or until ICU discharge or death, whichever occurred first. The primary outcome was all-cause mortality at 90 days. Secondary outcomes included all-cause mortality at 28 days, time to resolution of shock, recurrent shock, ICU and hospital length of stay, duration of mechanical ventilation, incidence/duration of renal-replacement therapy, incidence of new-onset bacteremia or fungemia and receipt of blood transfusion. At 90 days, there was no difference in mortality between the hydrocortisone group was 27.9% vs. 28.8% for the placebo group (OR 0.85, 95% CI 0.82 to 1.10; P=0.50). Notable differences in secondary outcomes include shorter time to shock resolution in hydrocortisone group (median 3 days vs. 4 days; hazard ratio, 1.32; 95% CI, 1.23 to 1.41; P<0.001), shorter time to ICU discharge in the hydrocortisone group (median, 10 days vs. 12 days; hazard ratio 1.14; 95% CI, 1.06 to 1.23; P<0.001), shorter duration of initial mechanical ventilation (median, 6 days vs. 7 days; hazard ratio, 1.13; 95% CI, 1.05 to 1.22; P<0.001). Fewer patients in the hydrocortisone group received a blood transfusion (37.0% vs. 41.7%; OR 0.82; 95% CI, 0.72 to 0.94; P=0.004). There were no significant differences in recurrent shock episodes, time to hospital discharge, recurrent need for mechanical ventilation, use of renal-replacement therapy or new onset bacteremia/fungemia. In summary, this double-blind, placebo-controlled RCT showed that in patients with septic shock requiring mechanical ventilation and vasopressor use for at least four hours, there was no mortality benefit at 90 days with administration of continuous IV hydrocortisone (200mg/day). However, the hydrocortisone group did demonstrate clinically and statistically significant improvement in a number of secondary outcomes, including faster time to shock resolution, shorter time to ICU discharge, shorter duration of initial mechanical ventilation and fewer blood transfusions, all without an increased incidence of new onset bactermia/fungemia.