Two studies were mentioned:
Hagihara A, et al. Prehospital Epinephrine Use and Survival Among Patients With Out-of-Hospital Cardiac Arrest. JAMA. 2012;307(11):1161-1168
See Ryan's blog for some great commentary.
The PACA Trial: Jacobs et al. Effect of adrenaline on survival in out-of-hospital cardiac arrest: A randomised double-blind placebo-controlled trial. Resuscitation. 2011 Sep;82(9):1138-43.