Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

A Couple of Comments on Bogus Ethics and Epinephrine in Cardiac Arrest – Part I


There are a couple of comments to Bogus Ethics and Epinephrine in Cardiac Arrest.

JB responded with this –

At the risk of dragging this slightly off the topic (because I agree, gutless politicians should get the hell out of trying to interfere with things that have been approved by plenty of ethics committees)…

Which raises the question, Is it possible to take something I wrote into an area that could be considered off topic?

Why the suggestion that adrenaline in cardiac arrest is useless? Yes, there is no evidence to suggest increased levels of survival to hospital discharge. But it’s not like we’re injecting orange juice into people’s veins (something which is probably also not going to increase that level!), adrenaline has been shown to increase the rate of ROSC. Isn’t ROSC a fairly important starting point?

Actually, I am suggesting that epinephrine may be harmful.

ROSC (Return Of Spontaneous Circulation) may be important, but if we cause neurological damage in order to get ROSC more quickly, or more often, is that good for the patient?

If I borrow money, I will have more money in my pocket/in the bank, right now. It is a good thing to have more money in my pocket/in the bank. If I am going to be in better shape later on to pay back the money, or if I am going to invest the money in something that will pay me back significantly more money later on, borrowing money can be a good thing.

Similarly, if I we stimulate the heart to work harder, in order to get ROSC more quickly/frequently, how much harm are we delivering for that result? Is this damaging the heart?

With drugs, there may be a Goldilocks dose. Too much produces more harm, than benefit. Not enough does not produce any benefit or harm. The Goldilocks dose is able to provide the most benefit and the least harm.

But does that exist for all drugs?

Probably not. We will never know if every drug has the potential to produce more benefit than harm at some dose, but we do know that many drugs are not used just because the doses that have been tested and the conditions they have been used to treat have not produced more benefit than harm.

Is 1 mg epinephrine the right dose to produce more benefit than harm?

We do not know.

Is there any dose of epinephrine that will produce more benefit than harm?

We do not know.

Is the benefit/harm balance dependent more on choosing the right patient, than the right dose?

We do not know.

What do we know?

More epinephrine does seem to produce more ROSC.

More epinephrine also does seem to produce more myocardial oxygen demand, which may lead to re-arrest, injury, ischemia, infarction, heart failure, arrhythmia, and any of the other heart problems that we try to get rid of.

More epinephrine is not routinely used in cardiac arrest (the old escalating dose epinephrine and high-dose epinephrine), because it does seem to produce worse neurological outcomes.

There are probably many other harms and benefits that are not known, or not worth mentioning.

The question is, How do we balance these harms and benefits of epinephrine?

Do we need to be more selective of the patients who are treated with epinephrine?

Do we need to adjust the dose of epinephrine that we give?

Do we need some way to determine what the right dose is for each patient?

We do not know, but we do not seem to be making much progress at answering these questions.

Maybe somebody should drop a house on us.

Good witch/Bad witch – which witch?

We can’t even tell if we are doing good.

The question is not – Are we witches? Of course, we are witches.

The question is – Are we good witches or bad witches?

To be continued in Part II and later in Part III.

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Comments

  1. ROSC can be dangerous to paramedic crews – pushing us to have to transfer dead people with lights and sirens through traffic. I wrote about it A few months back: http://flobach.com/2011/04/08/adrenaline-curse-or-cure/

    More discussions and more trials needed…