Question about cardiac arrest and defibrilation

[stas]

This is more of a regular medicine then diving medicine question but here it is. I ave been told by several sources that a deliberator can not start a heart, but only correct an irregular rithym. Meaning that if the person has flatlined, defibliration will not help them, you need do try to push some drugs through to restart electrical activity in the heart.
However, the padi rescue manual says that an AED should be used on a person in cardiac arrest as soon as possible to attempt to restart the heart. Now from what I understand, cardiac arrest does not necessarily mean flatline, but they are saying that an AED could RESTART a heart. Is this the case?

 

[tc]

AED's will not shock a flat line. They will only shock two conditions- ventricular fibrillation and ventricular tachycardia. The best chance for converting these is in the first eight minutes of the incident, hence the need to use the AED rapidly. If I recall correctly about 80% of "Heart Attacks" are initially ventricular fibrillation.

 

[moonlight]

That is correct. Defib will not start a heart. When we code a pt who is flat line we continue with cpr and push drugs. Some you get back, but usually only for a short while until they code again. When a AED is used outside of the hospital it will tell you to shock the pt or not. If the pt has a flat line then the only thing you can do at that point is cpr until help arrives with drugs. When we say a person is in cardiac arrest it can be the heart has stopped (flat line, asystole) or has a irregular heart beat ( ventricular fib, ventricular tachycardia).

 

[TSandM]

Organized electrical activity is necessary for organized contraction and pumping by the heart. Any condition which causes disorganized activity or markedly abnormal conduction of electrical signalling through the heart can result in inefficient or absent pumping of blood. In the field, and especially for the layman, diagnosing whether you are dealing with absent electrical activity (asystole, or what you are calling flatline) or ineffective electrical activity (ventricular tachycardia or fibrillation, or some other arrhythmia) can be difficult or impossible, depending on what equipment you have at hand and how trained you are in using it.

Since the only hope of survival is to restore organized electrical activity, the recommendation for the field rescuer is to shock. Shocking someone who has no electrical activity will do no good, but it will do no harm. Failing to shock someone who has Vfib because you don't recognize it on a monitor can lose a potentially salvageable life.

It is quite true that shock will not "restart" the heart. If there is no electrical activity at all, the likelihood of survival is extremely low, and we don't run those codes for very long. We do use adrenaline (epinephrine) to try to bring out any electrical activity which remains, or induce some if it's gone, but it's not terribly successful.

 

[ekremer]

BTW I have the DSAT (PADI) Emergency First Responder book infront of me and it only mentions a heart in ventricular fibrillation for a defibulator, and defines Cardiac arrest as when "something interferes with regular heart rhythms..."

 

[Ber Rabbit]

My father-in-law was saved by an AED. My husband performed CPR and could get him to gasp but he would fall unresponsive very quickly. The availability of an AED and the quick response of the in-house medical team at the Venetian in Las Vegas is the only reason my father-in-law is here today. My first aid/CPR training said "children need air, adults need electricity". Everyone should be AED certified, they are easy to use and tell you when to shock someone. Like TSandM said, you aren't doing any harm shocking if there's no electrical activity. You can't make a person any "dead-er".
Ber :lilbunny:

 

[divingmedic]

But you can do harm by shocking the heart when it does not need to be shocked. If you are using a monophasic instead of bipahsic you can actually fry the heart. While the majority of the newer AED are all biphasic there are still the older monophasic ones out there. Like others have said it should not let you shock them unless they are in V-Fib or Pulseless V-Tach.

 

[fisherdvm]

Whether or not an AED is biphasic or monophasic, it doesn't matter which you used, you can not make a dead person deader than dead, but you can bring them back to life.

If you got an AED, and it is monophasic, don't throw it away. Use it if you have to. It will not follow the new 2005 AHA guideline, and it will prompt you to stack the charges - ie. shock, shock, shock, then check pulse. Current guideline say, if the AED tell you to shock 3 times, just do it. Even if you were trained with the new AED guideline, ie, shock, cpr, check pulse, shock, cpr, check pulse.

There are biphasics sold in 2006 and earlier which are programmed to the old triple shock guidelines, and have not been reprogrammed to the newer guideline, again, if it prompt you to stack 3 shocks, just do it.

And there are some old AED programmed to meet the new guideline, but old prompts to check pulse is still left behind, and I guess, just do it, unless you remember the new guideline by heart, and will skip it until after you do the CPR.

Bottom line - don't throw old AED's away - they are still good, and they would not shock unless it is a rhythm that is shockable. And if you grab one, and it tells you to do things you were not trained in your AED class - just follow the prompts - as it is likely going to stack 3 shocks before telling you to resume CPR. It is an older AED, but still use it. If I am in cardiac arrest - just shock me, irregardless of the type of AED you found.

 

[fisherdvm]

The warning of "stand clear" is really important. One of my patient is a disabled RN who underwent defibrillator training with a supposedly modified trainer done by the hospital's biomed dept. I don't think it was a true ACLS class, but an introduction to ACLS.

Unfortunately, it was a live shock, and the current traveled through her right arm and damaged the nerves in the arm. Her arm swollen up twice it's size afterward, and now she has permanent paresis, and is on full disability.

I would be very worried if you are training with a real AED instead of a "training" AED. The current is quite strong, and is not intended to flow through a limb. I would not always trust the AED's not to fire unless it is a "shockable" rhythm either, especially if the pads are on my chest!