Written by Clay Smith
Epinephrine for out-of-hospital cardiac arrest (OHCA) improved overall 30-day survival (3.2%, epi vs 2.4%, placebo) but did not improve survival to discharge with a good neurological outcome. In fact, more patients who received epinephrine and survived had severe neurological impairment than in the placebo group.
Why does this matter?
The literature has been back on forth on epinephrine. Studies suggest it improves return of spontaneous circulation (ROSC), but those who survive long-term are neurologically devastated. This RCT was designed to clear this up.
Epi - It depends on how you look at it
This was a large RCT from the UK with 8014 adult, non-pregnant people with OHCA who received standard resuscitation care and either epinephrine or saline as placebo. Groups were well matched. Those who made it to the hospital received standard ICU care, including targeted temperature management. For the primary outcome, epinephrine significantly improved 30-day survival over placebo: 3.2% vs 2.4%, respectively. Consistent with prior studies, ROSC was much higher in the epinephrine group vs placebo: 36% vs 12%, respectively. However, there was no improvement in survival to discharge with good neurological outcome (defined as modified Rankin scale [mRS] ≤3) with epinephrine vs placebo: each around 2% with no statistical difference. Survivors to hospital discharge with severe neurological injury (mRS 4 or 5) were more common in those who received epinephrine vs. placebo: 31% (39/126) vs 18% (16/90), respectively. See Figure.
Now we must debate if getting more survivors, at the cost of them being neurologically devastated, is the right thing to do. Prior to the study they assessed public opinion and found that patients, "identified survival with a favorable neurologic outcome to be a higher priority than survival alone." Epi seems to be good for the heart but not the brain.
The authors also suggested we prioritize treatments with the most value in OHCA. The NNT was 112 for survival with epinephrine. Whereas for early defibrillation the NNT = 5 ; for early recognition of arrest, NNT = 11; for bystander CPR, NNT = 15.
A Randomized Trial of Epinephrine in Out-of-Hospital Cardiac Arrest. N Engl J Med. 2018 Jul 18. doi: 10.1056/NEJMoa1806842. [Epub ahead of print]. This is a free full text access article from NEJM.
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As you might have guessed, this blockbuster article already has garnered attention in the #FOAMed world.
- REBEL EM has a breakdown of the article and podcast.
- First 10EM has a great discussion of the issues.
- Rogue Medic weighs in as well.
- St. Emlyns has a thoughtful discussion of the pros and cons.
- EMNerd calls epi an ineffective therapeutic agent.
Reviewed by Thomas Davis