Here's another interesting piece of animal literature to fight with your IRB about for performing studies on human subjects in your ED. The article itself is a little hard to follow because of the terminology used - eCPR, SNPeCPR, and S-CPR, but, essentially, they have regular CPR, then they have their enhanced CPR which consists of an impedance device and compressive trousers, and then they have enhanced CPR plus sodium nitroprusside. Additionally confounding, on top of different CPR methods, they only gave standard CPR epinephrine, while the other two methods received no epinephrine. Sodium nitroprusside pigs did much better than the other two methods and medications.
So, with n = 8, in pigs, there's only a couple statistical conclusions we can make. Their pigs that received their no-drugs enhanced-CPR did no differently than standard CPR with epinephrine. Then, their pigs that received sodium nitroprusside plus enhanced-CPR do way better than their no-drugs enhanced-CPR. So, sodium nitroprusside is doing something. As far as external validity, 1) it's pigs and 2) it's probably financially and logistically infeasible for our ACLS-equipped paramedics to go through the additional steps of enhanced-CPR. I'd really like to see what would have happened in a blinded, three-arm, nitroprusside vs. epinephrine vs. placebo where each group had the same CPR.
That being said, if you can get your IRB to approve a prospective study in human subjects - more power to you. All the literature shows our current ACLS is mostly useless - and the definition of insanity is doing the same thing over and over again and expecting different results - so I'm all for looking at new agents in cardiac arrest.