Fig. 1. Distribution of patients according to baseline plasma cortisol concentration and response to cortisol-adrenocorticotropic hormone (ACTH) stimulation. Δ cortisol = delta plasma cortisol concentration 30 or 60 min after 250 μg of tetracosactrin infusion; HPAI = hypothalamic-pituitary–adrenal insufficiency; AI = adrenal insufficiency (see definition in Study Protocol—ACTH Stimulation Testing section); HR = hemodynamic responders (see definition in Study Protocol—Norepinephrine Dose Adjustment section).