The long awaited (you were all waiting for it right?) PARAMEDIC2 trial for epinephrine in “out of hospital cardiac arrest” (OHCA) is finally here from the UK. We all know and love epi. We give it every 2-5 minutes in codes but why are we doing it? How well does it help us in return of spontaneous circulation (ROSC)? Well I think for those of us that run codes on the regular we know all too well. How many times have you seen the heart beating only to hear someone say “It’s probably just from the epi”. We in the ED often see the ROSC but we don’t often get to enjoy the return of neurologic function (RONF). So, does epinephrine help us with ROSC and RONF or should epi make a BREXIT from ACLS? The PARAMEDIC2 trial looks to figure this out.
The Bottom Line
In this large double blinded RCT of 5 ambulance services in the UK, epi DID improve ROSC for the primary outcome of survival at 30 days (3.2% vs 2.4). However, favourable (that’s for you UK) neurologic outcome did not improve (2.2% vs 1.9%).
This was a randomized, double blinded, controlled trial of 5 ambulance services in the UK. One interesting note on this trial is that the process of obtaining written informed consent was deferred until later after resuscitation by either patient or legal representative. I’m not sure this could similarly be done in the US. The included population were adult patients who had sustained an out-of-hospital cardiac arrest for which advanced life support was provided by “trial trained” paramedics. Also, interestingly by “adults” they meant all patients age >16, apparently adult means something different to the brits! They excluded pregnancy, asthma and anaphylaxis. They also note that in one of the ambulance services, traumatic cardiac arrests were excluded. Which brings up an interesting point, this study took all comer cardiac arrest without discrimination; that is, medical and traumatic, shockable and non-shockable, witnessed and unwitnessed. One could make the argument that if you chose the right patient (witnessed arrest with shockable rhythm) you might see a signal of benefit. The results have been consistent with all the other trials thus far. Epi helps ROSC but doesn’t change much for favorable neurologic function. For the primary outcome, survival at 30 days, epi did show a benefit 3.2% vs 2.4% (unadjusted OR of 1.39 with a 95% CI from 1.06 to 1.82). They did multiple hypothesis generating (aka secondary) outcomes. The one of most interest to me is the favorable neurologic outcome at hospital discharge. This was a dismal 2.2% for epi and 1.9% for placebo with an OR that crosses 1 (no benefit). Lastly, some notable times in the trial were: median time from “911” call to arrival at the scene was 6.7 minutes, time between call and drug administration was 21 minutes, time to hospital arrival after ambulance departure was 12 minutes. ROSC at the scene was 36% with epi vs 11% with placebo and transportation of patient to hospital was 51% in epi vs 31% in placebo. What to do, what to do… It’s difficult to say stop using epi because of the ROSC is so high but in the end are we just bringing the heart back but not the brain? That looks to be the case.