The only reason we get away with giving such large doses of epinephrine to these patients is that they are already dead.

- Rogue Medic

When is a double dose of defibrillation a good idea?

 
In the comments to Double simultaneous defibrillators for refractory ventricular fibrillation, NCMedic and Ambulance Driver write that they have already begun using variations on double defibrillation.
 

That     is     excellent.

 


 

The changes in when to implement the change, as well as the vector to use, are reasons we need to have people publishing results on what is being done. Please, work with your medical directors and/or others to publish some results.

We have had epinephrine (Adrenaline in Commonwealth countries) in ACLS (Advanced Cardiac Life Support) guidelines, and our protocols, for decades, but we still do not know the best dose or even which patients benefit.

NCMedic writes –
 

Has been in our protocols for sometime now, we are finding it more beneficial sooner than later for obvious reasons, next protocol revision will most likely have it on the 4th shock with the 2nd set of pads placed A/P to cover from a different vector.

 

Epinephrine seems to be harmful when given later, or is epinephrine less beneficial later, or is epinephrine always harmful, just much more harmful later, or something else.[1]

The problem is that we do not know when, or for whom, epinephrine is indicated.

Epinephrine is probably indicated in some patients, but which patients, at what dose, and at what time? If epinephrine should be repeated all of the same questions apply to all further doses. Dr. Scott Weingart points out how little we know about the use of epinephrine, because his approach makes more sense than what ACLS recommends and the evidence is equally lacking.[2]

There are many things in the presentation to discuss, such as Dr. Weingart’s misunderstanding of what nihilism means, but that is for another time.
 

There does not appear to be any harm from double defibrillation. As we use more current more often, we should expect to learn of harms, as we do with almost every intervention. However, as NCMedic states, we may be doing harm by waiting too long to deliver the double dose.

Should it be a double dose?

What about 1 ½ times the maximum?

300 j bi-phasic or 540j mono-phasic or maybe some combination of bi-phasic and mono-phasic, and if a combination, what combination, with drugs or without, which drugs if with drugs, . . . ?

What about 3 times the maximum?

600 joules bi-phasic or 1,080 joules mono-phasic or . . . ?

Should the higher-dose defibrillation be after the fifth shock with a return to VF/pulseless VT (Ventricular Fibrillation/pulseless Ventricular Tachycardia)? After the fourth shock? After the third shock? After the second shock? After the first shock?

Is waiting longer to increase joules making it more likely that epinephrine will be given? Is epinephrine more harmful than a double shock, less harmful than a double shock, or roughly the same?

The amount we do not know is huge.

We should learn what we are doing to our patients and not arrogantly choose to remain ignorant, as we have chosen with epinephrine. That is changing, but some still defend the arrogance of ignorance at the expense of our patients.[3]

Footnotes:

[1] Does Faster Epinephrine Administration Produce Better Outcomes from PEA-Asystole?
Sun, 25 May 2014
Rogue Medic
Article

[2] Podcast 125 – The New Intra-Arrest from SMACCgold
EMCrit
Dr. Scott Weingart
Web page with video and show notes.

[3] Effect of adrenaline on survival in out-of-hospital cardiac arrest: A randomised double-blind placebo-controlled trial
Jacobs IG, Finn JC, Jelinek GA, Oxer HF, Thompson PL.
Resuscitation. 2011 Sep;82(9):1138-43. Epub 2011 Jul 2.
PMID: 21745533 [PubMed - in process]

Free Full Text PDF Download of In Press Uncorrected Proof from xa.yming.com
 

This study was designed as a multicentre trial involving five ambulance services in Australia and New Zealand and was accordingly powered to detect clinically important treatment effects. Despite having obtained approvals for the study from Institutional Ethics Committees, Crown Law and Guardianship Boards, the concerns of being involved in a trial in which the unproven “standard of care” was being withheld prevented four of the five ambulance services from participating.

 

In addition adverse press reports questioning the ethics of conducting this trial, which subsequently led to the involvement of politicians, further heightened these concerns. Despite the clearly demonstrated existence of clinical equipoise for adrenaline in cardiac arrest it remained impossible to change the decision not to participate.

 

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Comments

  1. An interesting animal study I just saw seemed to indicate that using Peak Energy / Peak Current is *not* as good a measure of probable shock success as Average Current when utilizing biphasic devices.

    Keeping in mind the small numbers so no comment on if this affects anything, but it did show that some devices with advertised higher peak energies actually did not deliver any higher average currents due to waveform tilt/duration changes.

    (The authors did note that this was in an electrical-induction of VF model rather than an ischemic model, but I’m not so sure that would be as relevant. Perhaps given their small numbers it could introduce a positive bias, but I would have imagined it to be equal between the two groups.)

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