# Stopping CPR for AED



## mtnrescue (Nov 7, 2008)

So I got a newbie question.  I need to find out how long you can stop CPR to administer a shock with the AED.  I've heard answers anywhere from 45 to 90 seconds, but nothing definite.


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## JPINFV (Nov 7, 2008)

As long as it takes the machine to analyze and if need be, shock.


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## Scout (Nov 7, 2008)

yup all our AEDs will tell you stop, analising do not touch,,,,,,,,,,, shock advised, press the shinney button of wonder and Thump, resume CPR,,,



so as long as it tells you to wait.


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## traumateam1 (Nov 7, 2008)

Like everyone has said, it depends on how long the machine takes to analyze, charge, and deliver the shock. AED's these days are becoming quicker and quicker at doing this process. When it says to stop, you stop, after the shock has been delivered than you resume CPR.


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## traumateam1 (Nov 7, 2008)

As we all know, CPR builds up pressure to keep moving oxygen rich blood to the brain. Whenever you stop CPR, for whatever reason that pressure starts to decrease and the blood stops flowing to the brain, then you have to build up the pressure again until blood is flowing effectively to the brain. You should minimize the amount of time that CPR has to be stopped. So don't delay CPR after an AED shock, you should immediately resume CPR.

Here is a good link:

http://publicsafety.com/article/article.jsp?id=3063&siteSection=11


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## JPINFV (Nov 7, 2008)

traumateam1 said:


> So don't delay CPR after an AED shock, you should immediately resume CPR.


Too bad the question is about how long to stop CPR to deliver a shock, not how long to delay CPR following an analysis and shock.  




mtnrescue said:


> I need to find out how long you can stop CPR to administer a shock with the AED.  I've heard answers anywhere from 45 to 90 seconds, but nothing definite.


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## traumateam1 (Nov 7, 2008)

traumateam1 said:


> *Like everyone has said, it depends on how long the machine takes to analyze, charge, and deliver the shock.* AED's these days are becoming quicker and quicker at doing this process. When it says to stop, you stop, after the shock has been delivered than you resume CPR.



I understand what the question was. There is no definite answer, it's however long the AED takes to do it's thing. If you would have read what I posted than you would of seen my _first_ sentence, and realized I answered the question.


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## mtnrescue (Nov 7, 2008)

Thanks for all the replies.  The reason I ask is I have a take home test and that is the last question.  It requires an actual time limit.  It's not in our books, we are supposed to research the question and I am coming up dry everywhere I look.


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## jochi1543 (Nov 7, 2008)

mtnrescue said:


> Thanks for all the replies.  The reason I ask is I have a take home test and that is the last question.  It requires an actual time limit.  It's not in our books, we are supposed to research the question and I am coming up dry everywhere I look.



Hm, maybe interpret it from the POV of breaths. If the patient can't breathe on his own and you have to stay clear for 10 mins while the AED is doing its thing, he's gonna be brain-dead, anyway. So however long you think the patient is able to remain without oxygen delivery - that's how I'd approach this if I didn't know an answer.


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## MRE (Nov 7, 2008)

In practice you can minimize the time CPR is stopped by having one person apply the pads while the other does compressions, and only stop once the machine is actually going to start analyzing (after it instructs you to apply pads, etc.)

If you can't find an actual number, write up a good description of the procedure and how to minimize the time CPR is stopped.  Your instructor may feel that this is good enough or even better than being able to recite a number from memory.


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## mtnrescue (Nov 7, 2008)

I already got bonus points for rattling off the steps the AED takes assessing the patient through advising shock or not.  He might just be screwing with us but I have to try.  We are finishing up Cardiac Emergencies so it might just be a way to make sure everyone is efficient with the AED.


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## FLAEMT22 (Nov 8, 2008)

Don't ever stop CPR before having the pads hooked up. Once you know you're ready to hit analyze then you can stop CPR, but again like someone else described above, this is only for as long as the machine tells you to. In other words, once it is done analyzing you should either shock or go back to CPR depending on what is dictated by the AED. LifePack or manual defibs are different, obviously. You continue CPR until you are ready to shock.


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## ryanbg (Nov 12, 2008)

Where I work, our hands don't leave the chest (unless absolutely necessary to shave or sheer), until the pads are on and the AED tells us to not touch  but when you consider a lifesaving shock after a solid 2 minutes of CPR (I think that's the latest protocol now for AHA) I think it's worth it. After all, the faster you treat a condition like VF or VT, the better chance they have to survive. As long as your machine is up to date with the latest standard, you shouldn't worry about it.


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## mtnrescue (Nov 13, 2008)

*Got the answer*

So we got the answer.  Somewhere in some text book the instructor has it states the "maximum" time you can stop CPR to use an AED is 90 seconds.  Although the amount of time an AED takes depends on the make and model this is the max.  Thanks for all the help.


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## WuLabsWuTecH (Nov 13, 2008)

Yeah, 90 seconds seems a bit long, but once again, always follow the AED.  If you get an OLD AED with the stacked shocks, then follow that.  We were taught when intubating that you do it for as long as you can hold your breath for since when yo uneed a bearth, your pt needs a breath.  I would have gone with that number since CPR also requires breathing for the pt.


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## ResTech (Nov 13, 2008)

AED applied and 3 shocks delivered in 90 SECONDS = AHA Guideline


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## ryanbg (Nov 13, 2008)

WuLabsWuTecH said:


> Yeah, 90 seconds seems a bit long, but once again, always follow the AED.  If you get an OLD AED with the stacked shocks, then follow that.  We were taught when intubating that you do it for as long as you can hold your breath for since when yo uneed a bearth, your pt needs a breath.  I would have gone with that number since CPR also requires breathing for the pt.


Is it still acceptable/legal/etc... to use the stacked-shock machines? That's what we were trained on and how to use them with that protocol, and then we got the new CPR-Shock-CPR-Shock, etc... Which kind of threw a wrench in our gears but oh well.


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## tydek07 (Nov 16, 2008)

mtnrescue said:


> So I got a newbie question.  I need to find out how long you can stop CPR to administer a shock with the AED.  I've heard answers anywhere from 45 to 90 seconds, but nothing definite.



The machine will tell you what it is doing and what to do. When it tells you to stop, you stop, also stop touching the patient, as it is going to check the rythym. When it tells you its gonna shock, you stay back until it tells you to push the shock button. When it tells you to start cpr, you start cpr.

HaHa, very simple. Just follow and do what the machine tells you. ^_^

Take Care,


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## medicdan (Nov 16, 2008)

*The science behind it (as I understand it). (Long answer!)*

I was just this weekend at an EMS symposium and heard a very interesting lecture by a Doctor on the AHA National Faculty-- about new research on Resuscitation. I can’t say I fully understood everything he was saying, but found it all fascinating. I will try to replicate some of the analysis here- get in touch with me if you would like citations. And please, for those that understand, explain! I do have a point that relates to the OP, just stick with me please!

There was a lot of discussion about quality CPR, the relationship between CPR, defib and survival, as well as new interventions in resuscitation medicine.

Quality CPR-- even with very good compressions, it can only reproduce ~15% of the cardiac output of a normally beating heart-- that means that there is only 10%-20% normal blood flow to the heart and 20%-30% normal blood flow to the brain. There was discussion about ROSC and its correlation to CPP (coronary perfusion pressure), which is indicative of tissue perfusion and end survival potential.

The doctor then showed the results of pressure sensors during CPR. At a rate of 15:2 and a rate of 110 compressions/minute CPP only approached reaching its goal toward compression #12—then it dropped off for breaths, and took another 12 compressions to regain its pressure. In order to maximize CPP, and thus survival, high quality CPR needs to be performed (good rate, depth, uninterrupted shock, release and ventilation all need to be “perfect). 

In a study done of CPR quality out-of-hospital researchers found that chest compressions were not delivered 48% of the time (the target is 20%). ECG analysis and defib accounted for only a small part of the interruption (15-20% of the time). A JAMA study found that 38% of CPR done in-hospital was too shallow and 60% of CPR done in the field is too shallow. 
Another study was done testing CPR skill retention. A group of med students were taught layperson CPR, then two weeks later were tested—and they took up to 16 seconds (of hands-off time) to give breaths. 
Some barriers to quality CPR include pauses for procedures (intubation, IV, pulse checks, etc), pausing for rhythm analysis, pausing after shock to recheck rhythm, pausing to charge, clear and shock, and a general unawareness of clinicians to the importance of CPR.  

Bringing this all back to the street (and BLS). Older AEDs would often take an average of 54 seconds between arrival and the first shock (telling you to call for help, taking through resps, analyzing, etc.), and an average of 100 seconds to deliver 3 shocks in sequence. Newer AEDs only take between 30 and 40 seconds to deliver the first shock (and don’t to sequence shocks anymore). New technology is being incorporated (we are already starting to see it elsewhere) to provide feedback to the responder as to the quality of their compressions, and more importantly, analyze the rhythm while compressions are being done (keeping up CPP), and being able to "tune out" the manual compressions. This will dramatically decrease "hands-off" time for AEDs-- and improving survival rates.  

There is a lot more in this, and I apologize for the length, but it is of  importance to the OP’s question. The take home message is that way too often compressions are being done too shallowly, too slow, and inconsistently, and thus, the heart and body are not getting the popper perfusion they need. The pauses in compressions are really serious detriments to patient survival—and anything that can be done to minimize or stop the interruptions can (and does) lead to higher survival rates.


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## LifeLine (Nov 25, 2008)

emt-student said:


> ...A JAMA study found that 38% of CPR done in-hospital was too shallow and 60% of CPR done in the field is too shallow....
> 
> ....New technology is being incorporated (we are already starting to see it elsewhere) to provide feedback to the responder as to the quality of their compressions, and more importantly, analyze the rhythm while compressions are being done (keeping up CPP), and being able to "tune out" the manual compressions....



Just a heads-up.  That technology is already here. I know the Zoll AED Plus has this technology. This was taken from their website.

http://www.zoll.com/product.aspx?id=75



> ZOLL's AED Plus® features Real CPR Help®, a tool that is able to actually see what you are doing and provide feedback to help you do it well. Audio and visual prompts help you rescue with confidence and clarity unmatched by any other automated external defibrillator (AED).
> 
> Not pushing hard enough? It will tell you when to push harder.
> Pushing hard enough? It will say, "Good compressions."
> ...


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