Shockable Rhythms

[Achromatic]

I'm jumping the gun a little (I prefer to call it 'being prepared'), but I had a question that came up following doing the AHA CPR course last weekend (our dept actually uses it as a pre-req for EMT-B training, which the county does in-house, using results from the practical and written to determine placement in EMT training)... anyway:

Using an AED, it will analyze, and shock VF and VT rhythms.

Are these the only shockable rhythms? (I know they are the only ones the AED will shock.) I know(?) you can't shock asystole, much to the surprise of many TV hospital shows, but say your ALS upgrade arrives with 5/12 lead ECG and a manual defib, are there other rhythms that are shock candidates? A-fib? Bradycardia? SVT?

Not that I'll be doing these as BLT, I just like absorbing knowledge - any good web resource on the above?

 

[Shishkabob]

Vfib and pulseless Vtach are the only ones you can defib with an AED, but there are others you can "shock" with a monitor/defib depending on how you define it.

There's something called transcutaneous pacing, which basically acts as a pacemaker for the heart, telling it to beat. You use it for things such as a bradycardia that causes shortness of breath / altered mental status / low BP.


Another way you can shock is cardioversion, which is essentially defibrillating, but on the peak of the R wave in the QRS complex.

This is used for things such as symptomatic Vtach with a pulse, and SVT. It's done on the peak of the R wave because if it's timed wrong, and falls on the downslope of the T wave, you can cause very bad things to happen.

 

[Achromatic]

Ahhh, I see. I'd heard of pacing, and I'd pretty much presumed it is what it is, so thanks for the clarification.

I'm guessing, too, that cardioversion is something you'd want to feel pretty confident at before attempting in a moving rig?

 

[Shishkabob]

Any time

The newer monitors/defibs have a "Sync" button, where when you press it down, the computer automatically detects the R wave and discharges at the correct time.

 

[Achromatic]

Any time

The newer monitors/defibs have a "Sync" button, where when you press it down, the computer automatically detects the R wave and discharges at the correct time.

Ahhh, that would make sense

 

[Shishkabob]

Oh, thought I'd add something else:

A-fib technically CAN be shocked / medicated, but it more then likely won't. The atria has been contracting wildly without actually pushing much blood, and because of such, clots can form in the atria. If you shock them or push Diltiazem, and it works, it will end up pushing the formed clot and either causing a pulmonary embolism or a stroke.

The cut off, depending on who you're talking to / protocols, is 48 hours.

 

[absolutesteve81]

Don't forget SVT where you identify WPW (Wolff Parkinson White). Adenosine would be a no-no therefore you would jump straight to Cardioversion

 

[Akulahawk]

The idea behind the synch cardioversion is to get the entire heart to depolarize simultaneously... This means that all the normal "pacemaker" nodes, any ectopic sites, and all other cells all depolarize... and then, the theory goes, the normal pacing sites take over normal cardiac conduction...

Sparking the patinent right on top of the T-wave results essentially in an "R on T" phenomenon... which can kick-off lethal arrythmias.

Sacramento never had adenosine in its arrythmias protocol... precisely for the reason that the narrow complex tachycardia (SVT) really is the WPW... and goes straight to electrical therapy for unstable patients. This stems from Sacrameto's history of being LALS... and in ways, Sacramento EMS is stuck in that LALS mentality. Allowing (and trusting) it's Paramedics to identify various types of SVT and VTach rhythms goes against the LALS mentality...

We'd have Cardizem, Procainamide, adenosine, and Amiodarone... and we have none of those...

But at least we have Versed... We used to only have Valium... then they added the Versed... and now they prefer using just the Versed. Probably better that the patient not remember the cardioversion...

 

[Dominion]

Don't forget SVT where you identify WPW (Wolff Parkinson White). Adenosine would be a no-no therefore you would jump straight to Cardioversion

I'm curious about this, I've seen and heard different things. I've heard the above from an instructor during our cardiology/ACLS sections. I've seen other medics say it, I've seen cautions such as administer only if cardioversion is immediately available. I have also seen no cautions or warnings and have the "In presence of SVT, administer Adenocard unless patient is unstable or poor perfusion in which case perform immediate cardioversion."

What is the proper answer? Per protocol? My nursing drug reference, flip book, state protocols, epocrates, and drug packet do not even mention WPW.

 

[futuremedic]

Oh, thought I'd add something else:

A-fib technically CAN be shocked / medicated, but it more then likely won't. The atria has been contracting wildly without actually pushing much blood, and because of such, clots can form in the atria. If you shock them or push Diltiazem, and it works, it will end up pushing the formed clot and either causing a pulmonary embolism or a stroke.

The cut off, depending on who you're talking to / protocols, is 48 hours.

You mean can be cardioverted??? It is not a shockable rhythm, you only want to cardiovert if it is less than 48 hours or the patient is unstable.

 

[HotelCo]

You mean can be cardioverted??? It is not a shockable rhythm, you only want to cardiovert if it is less than 48 hours or the patient is unstable.

And the chances of cardioverting in the field (if the patient is stable and AFib is less than 48 hours) is slim to none.

 

[Dominion]

Thanks guys in chat, question answered and understood

 

[Shishkabob]

You mean can be cardioverted??? It is not a shockable rhythm, you only want to cardiovert if it is less than 48 hours or the patient is unstable.

No, I meant shocked, as in the slang for sending electricity through someone, be it pacing, cardioverting, or defibrillating.

And besides the fact that cardioverting already basically IS defibrillating, with minor differences (well... a few hundred joules minor )


Shock, bake, cook, fry, electrify. Whichever you want to use

 

[MrBrown]

defibrillation is unsyncronised cardioversion; what we refer to as "cardioversion" is technically syncronised defibrillation at lower energy levels

 

[Melclin]

I don't know why you blokes get so caught up in the difference between cardioversion and defib and shocking and so on.

Cardioversion just means converting the rhythm whether its synchronized or unsynchonised, chemical or electrical. Defibbing a person in VF is cardio version, just as giving a glass of ice water to a person who pops into A-fib is cardioversion. Usually when using the term cardioversion, most people are referring (medics anyway) to electrical synchronised cardioversion. But it doesn't strictly mean that.

And as you say linuss "shocking" is slang. It can refer to anything you want it too.

 

[Melclin]

Damn it brown. You beat me to the punch.

 

[futuremedic]

No, I meant shocked, as in the slang for sending electricity through someone, be it pacing, cardioverting, or defibrillating.

And besides the fact that cardioverting already basically IS defibrillating, with minor differences (well... a few hundred joules minor )


Shock, bake, cook, fry, electrify. Whichever you want to use

Try using your slang when you are testing for the registry and see how well that goes. There is a difference in joules as well as making sure that it is synchorinized at the proper time so you don't knock the patient into asystole.

 

[Melclin]

Try using your slang when you are testing for the registry and see how well that goes. There is a difference in joules as well as making sure that it is synchorinized at the proper time so you don't knock the patient into asystole.

Really? Here I was thinking when Linuss said A-fib was a shockable rhythm that I should go and give 360 to the next old lady I find in a nice stable long term A-fib.

Linus you really shouldn't use slang like that, especially not on a forum where we all know what you mean... just in case the national registry starts testing people based on casual conversations.

 

[futuremedic]

Really? Here I was thinking when Linuss said A-fib was a shockable rhythm that I should go and give 360 to the next old lady I find in a nice stable long term A-fib.

Linus you really shouldn't use slang like that, especially not on a forum where we all know what you mean... just in case the national registry starts testing people based on casual conversations.

You may understand it but the next person might not.

 

[Shishkabob]

Try using your slang when you are testing for the registry and see how well that goes. There is a difference in joules as well as making sure that it is synchorinized at the proper time so you don't knock the patient into asystole.

I did already state those differences and infaxt one was in the post you just quoted.

" (well... a few hundred joules minor)"

and besides, depending on protocols, the only energy setting that's different is the first one at 100j on a monophasic system. After that, it's the normal 200,300,360 (if you follow AHA)