It’s interesting, when I started we were still giving Bretylium, until the plant burned down and survival rates didn’t drop. I think time down prior to CPR/defibrillation, time down until ALS care and quality of CPR probably play a factor in conjunction to epi administration. I’ve had rhythms return after the fourth or later epi admin but I’m not sure of what rhythm they were in at the time. Survival to 3 months/6 months/1 year post cardiac arrest should really be the bench marks for out of hospital success in cardiac arrest not survival to admission/discharge.
