Friday, 30 January 2015

Is Epinephrine (Adrenalin) During Cardiac Arrest Associated with Worse Outcomes?

Answer: yes of course.

But does it cause worse outcomes? Who knows- and this study does not help us find the answer.

This was registry review over a 12 year period at a single centre in Paris designated as a “cardiac arrest receiving hospital.” They looked at non-traumatic out of hospital cardiac arrest with ROSC. They compared the group that got adrenalin to those that didn't. The primary outcome measure was favourable neurologic outcome at discharge from hospital.

As you could guess, the cohort that got adrenalin was sicker in every possible way. They were less likely to be witnessed arrests, less bystander CPR and less likely to have initial shockable rhythms. By their very nature, they were more prolonged arrests.

Therefore it should come as no surprise that the adrenalin group did much worse. Only 17% of the adrenalin group had a good outcome vs. 63% that did not get adrenalin. Of course the authors recognized this bias and performed all kinds of adjustments, regression analysis, propensity modelling and bootstrapping. When was the last time you bootstrapped?

Given the study design, these adjustments are all very appropriate. But it should be emphasized that a lot of assumptions go in to this analysis and it is far from perfect.

After adjustments, the authors conclude that the use of adrenalin was negatively associated with favourable neurological outcome. They were careful not to address causation and rightfully suggest further study.

Should this study change our practice? No.

This was not an RCT and can really only raise a hypothesis for further study. I think a properly powered RCT would certainly be feasible. But the late Ian Jacobs tried this in Australia and ran in to a huge political & “ethical” roadblock. Nevertheless, this is more evidence that suggests that adrenalin may cause more harm than benefit.  I hope we will find a definitive study one day.

Covering:

Dumas F, Bougouin W, Geri G, et al. Is Epinephrine During Cardiac Arrest Associated with Worse Outcomes in Resuscitated Patients. J Am Coll Cardiol 2014;64:2360-2367.


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