Early stress-dose steroids are of uncertain efficacy in cardiac arrest. The current authors plan to conduct a pertinent mediation analysis using prospectively collected data from 2 prior randomized clinical trials of in-hospital cardiac arrest. These trials reported positive results on the vasopressin-steroids-epinephrine (VSE) combination. The current analysis is aimed at identifying mediators of the benefit associated with VSE, potentially attributable to its stress-dose steroid subcomponent. Tested mediators will include arterial pressure in the early postresuscitation period (primary), and arterial blood lactate in the early postresuscitation period and renal failure free days (secondary).