AED Question

FlorianFred

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My first time posting a question, and I feel the need to start with 2 things: I'm MFR/EMR, not an EMT; and I apologize in advance if this has been addressed somewhere else on the site....feel free to just paste the link and I'll read that thread.

As a volunteer fireman who tries to go on every single medical call that comes through, I've seen several instances of "non-responsive, not breathing". During the times I've been called on to do CPR, the EMT/Paramedics will usually hook up a monitor and what looks like an AED. In every instance (only 3 for me so far, I'm still new), the "shock" function has never been used....someone will ask us to stop CPR, check for pulse, and then say "dumping the charge, continue CPR". After 45 minutes (sometimes only 30 minutes) a call is made to the local hospital and the time of death is delivered from the physician.

From the EMR training, I know the machine (and or professionals on the machine) dictates when/if the "shock" is delivered; but I've yet to see it delivered. If there is no pulse, and no activity registered in the heart, wouldn't you throw electricity at them as a last resort? Or have I watched too much TV (and yes, that is a rhetorical question)?
 

mgr22

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AEDs are programmed to deliver shocks when they detect a small, lethal subset of heart rhythms. Massive jolts of electricity won't help the others, and could be harmful in situations where the heart is working but a pulse isn't detected.

Shocking everyone would be sort of like giving epi to everyone in case they're having a really bad allergic reaction. The epi would likely kill some who have totally different problems.
 

akflightmedic

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I will take a stab at explaining this on a very basic level, and if it is too basic, I apologize.

And yes, TV has created many unrealistic expectations, creative scenarios, and been flat out wrong with so many scenes. For example, we NEVER defibrillate "flat line".

The heart has two modes of working. There is an electrical mode and then there is the mechanical mode. The electrical mode makes the heart do the physical part (contract).

There are two rhythms we will shock with an AED. These are ventricular fibrillation (VFib) and ventricular tachycardia (VTach). The ventricles are the two chambers at the base of the heart, they do a lot of the pumping/squeezing work.

Vfib means the heart is quivering, think like a bowl of jello. It quivers, but it does not contract and pump blood.

VTach means the ventricles are contracting but they are doing it so fast, there is no blood pumping. The chambers do not have time to fill with blood.

When someone collapses, they are typically in one of these two rhythms, usually it is VFib. This means, the heart is still trying to pump, it is still getting electrical impulses, and it is trying physically to do so, however it is failing.


**BIG PLOT TWIST....the AED is NOT similar to "jump starting" a dead battery. So many people have that concept wrong (thanks TV) and I imagine you also think that way, since you said "throw electricity as a last resort". The AED delivers a shock NOT to start a heart that is not beating...instead in very simple terms here, it delivers a shock to STOP a heart that still has movement, and then hope the natural rhythm resumes.

So if the heart has NO movement, this means there are no electrical impulses being generated within the body. This means there is nothing to shock. We do not shock "flat line" properly called asystole (A-sis-tuh-lee).

Sometimes, by doing compressions very early, and correctly, we can build up enough of the chemical in the heart to prolong the VF/VT phase in order to buy time until an AED arrives. These are the only two things which really lead to regaining a pulse or surviving a cardiac arrest. You need early CPR with great compressions and you need the AED very quickly.

So the majority of the cardiac arrests you respond to, just know they are unlikely to survive. In my area, we work an arrest for 20 minutes and if there is no return of pulse during that time, we terminate our efforts. We do not have to call anyone. We do not transport bodies and we do not work more than 20 minutes if there is no Return of Spontaneous Circulation (ROSC) which means get a pulse back.

Hope this helps...
 

NomadicMedic

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I explain the AED shock is similar to pushing CTRL-ALT-DEL on your computer to reboot it. We hope that the shock will reset the electrical system in the heart and allow it to beat normally
 

Akulahawk

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You can't shock asystole...in a nutshell
Sure you can... but just because you can, it doesn't mean you should.

In computer terms, it's like doing CTL-ALT-DEL on an unplugged computer.
 

johnrsemt

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TV they shock everything; I have been yelled at for not shocking patients, because "You didn't give grandma every chance to survive, because you didn't shock her (even though she was dead for 3 days). So then you have to try and explain it to the family, and then the supervisors
 

mgr22

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TV they shock everything; I have been yelled at for not shocking patients, because "You didn't give grandma every chance to survive, because you didn't shock her (even though she was dead for 3 days). So then you have to try and explain it to the family, and then the supervisors
The family, I can understand. But supervisors?
 

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