Shock into Asystole?

[Simusid]

I learned about a cardiac arrest in my community recently. As often happens, the police were on scene before us. They do CPR and we provide them with AEDs. In this case, I know that the patient was shocked once and our paramedics were on scene almost immediately following that. I then heard that the medics saw an initial rhythm of asystole.

I do not know the quality or duration (2 min?) of cpr provided by the police and I assume that they resumed compressions immediately post-shock.

I'm taught that a witnessed arrest can be defibrillated immediately because the heart is electrically "ready" to be restarted up until about 4 minutes. Unwitnessed arrests, or unknown downtime require 2 minutes of CPR to "re-prime" the heart with O2, glucose, ATP or whatever.

So my question is, is asystole a known modality for a post shock rhythm where there had been inadequate CPR?

 

[Aidey]

I wouldn't assume the asystole is due to poor CPR. Whatever caused the guy to drop may have done so much damage to his heart that the rhythm would have deteriorated no matter what happened.

 

[Simusid]

I wouldn't assume the asystole is due to poor CPR. Whatever caused the guy to drop may have done so much damage to his heart that the rhythm would have deteriorated no matter what happened.

Thanks. I definitely get that some patients are going to end up in asystole. I was picturing a case where the cop shocked and almost immediately the pt was in asystole, so I thought there could be more going on.

 

[DesertMedic66]

Well the shock does stop the heart...

 

[jefftherealmccoy]

Thanks. I definitely get that some patients are going to end up in asystole. I was picturing a case where the cop shocked and almost immediately the pt was in asystole, so I thought there could be more going on.

I've had patients that after CPR (not bystander CPR) and a rythm of v-fib were shocked and went right into asystole. (dispite the AHA guidelines to start right back up with CPR a lot of guys can't wait to see that rhythm) It's happened quite a few times in my short career actually. So I don't think it's the CPR. Some hearts just give up.

 

[Simusid]

Well the shock does stop the heart...

Agreed! And that is sort of what I was trying to say (but I did it poorly). If the heart needs 2 min of CPR to be able to start, and if it doesn't get that then maybe it would contribute to the inability to recover after being shocked.

 

[Mariemt]

It is expected post shock.

 

[Mariemt]

Agreed! And that is sort of what I was trying to say (but I did it poorly). If the heart needs 2 min of CPR to be able to start, and if it doesn't get that then maybe it would contribute to the inability to recover after being shocked.

most will be unable to recover after cardiac arrest anyway

 

[jwk]

I do elective cardioversions in our cardiology department for A-fib/flutter. 99+% of the time, they either convert to a sinus rhythm, or the rhythm is unchanged. The other 1% end up in asystole - hate it when that happens - but they've all come back with immediate and agressive CPR and epi/atropine.

 

[Mariemt]

The only time an aed will shock is v tach and v fib. A regular aed should not shock for afib . It is expected to stop the heart and CPR to restart. I say expected because it can shock it in to a normal rhythm , but usually in a case of cardiac arrest, it will stop it all together and allow CPR to start the normal rhythm

 

[TomB]

Yes, if the pre-shock coronary perfusion pressure is less than 15 mm Hg you will almost always shock the rhythm into asystole. This is why it's extremely important to perform comrpessions while the capacitor is charging and minimize the peri-shock pause. The pre-shock pause is more important that the post-shock pause but both are important.

 

[Handsome Robb]

Yes, if the pre-shock coronary perfusion pressure is less than 15 mm Hg you will almost always shock the rhythm into asystole. This is why it's extremely important to perform comrpessions while the capacitor is charging and minimize the peri-shock pause. The pre-shock pause is more important that the post-shock pause but both are important.

It's like pulling teeth to get some fire crews to do compressions while I charge the monitor. I'm not going to light you up I promise.

 

[MasterIntubator]

It does happen, even with the best CPR. I have a few code summaries that show that.... V-fib pre defib.... and asystole post.

Still workable. Does not mean they are any "deader". I wish they would come back with pacing during CPR.... it seemed to work.