AED Protocol

[*Lifeguard*]

AED Protocol for a witnessed arrest and arrest due to asphyxia requires 2 minutes of effective CPR prior to applying the AED. What is the rational behind this protocol?

[Canadian Caesar]

To me it seems the answer is this:

- In a traditional witnessed arrest, you know there is a chance that the heart is still being supplied with enough oxygen and nutrients to favor a positive response to immediate defibrillation.

- In a witnessed arrest that is due to asphyxia, you know that most likely the heart has a lack of oxygen, so the odds of electricity helping are very slim until you correct that problem.

The 2 min. of CPR is meant to supply the heart with enough oxygen and nutrients so that the muscle is at least capable of sustaining a heartbeat after AED use.

So in other words, arrest due to asphyxia presents the same situation as an unwitnessed arrest for the EMS provider.

In both cases, there is a great possibility that the heart muscle is chemically unable to beat in a hypoxic state and AED use will be largely unsuccessful until the heart is re-oxygenated by CPR.

Does this answer your question? Does anyone have anything else to add?

[CBEMT]

Does anyone have anything else to add?

Yeah, I want to know if he slept through CPR class.

[Timmy]

Witnessed or not get the defib on ASAP is my rational.

[AnthonyM83]

Perfect answer Julian.

I don't think the concepts of CPR really stick until EMT class when you have it more than once and are tested on it.

Another concept often confused (because taught as algorithm) is when to do 2 min CPR or when to call 911 first.

The way I teach it:

-Pediatrics - main concern is respiratory, so don't run off without making sure they have some oxygen in body.

-If witnessed, you know they have it because they were just breathing.

-If uwitnessed, probably down long enough to use up the oxygen, so leave them with something (2 min of CPR) while you go call.

-Adults (non-asphyxiated) - main concern is cardiac, so just go get 911 (and thus AED) as fast as possible.

(Still do 2 min right before shocking to prep the heart).

[Novisen]

http://www.jolife.com/doc/LUCAS-White-paper.pdf

[irme]

Witnessed or not get the defib on ASAP is my rational.

The problem with this Timmy is that if the rhythm is shockable the AED will require you to shock and go through all of the rhythm analysis. Most AED's do not let you conduct CPR for 2 minutes. There is massive evedince that hypoxic hearts correlate with poor outcome in cardiac arrest.

If you are not EMS trained, used the AED as its meant to be - put it straight on. If its witnissed by you, and your EMS shock immediatley. If its not witnessed by you but effective CPR has been taking place since response I would be inclined to shock. 10% of myocardium per minute remember!

[Timmy]

Interesting. I haven’t really put much thought into it. I guess witnessing an arrest is not an everyday occurrence. But you learn something everyday! Thanks guys.

[JPINFV]

Does this answer your question? Does anyone have anything else to add?

If I remember reading the guidelines correctly when they first came out, patients in v-fib on an unwitnessed arrest are normally found in fine v-fib. Fine v-fib is more likely to convert into asystole whereas 2 minutes of CPR can 'covert' fine v-fib into coarse v-fib. Coarse v-fib is more likely to result in ROSC following defibrillation.

[Just Plain Ruff]

unfortunately Timmy, the most common time we as EMS providers will witness an arrest is when the patient is in the back of the ambulance or we are already there. The majority of arrests are already happening when we get the call.

Put the AED on but don't turn it on, do your 2 minutes of cpr and then turn it on. That will fix your desire to put the AED on and get it ready and it will allow you to do 2 minutes of CPR.

But Julian, the answer you gave was spot on. As a matter of fact I have a physician I'm working with today and I showed him your answer and he as an ER doc would not offer any more than that. He was impressed.