beeeeep, CODING!, paddles, clear!, *spasm*, beep beep beep beep

[alterego]

A very compelling part of medical dramas is when the patient's heart stops and then the medical staff are magically able to restart said patients heart with a single charging and application of the paddles. Can anyone with more familiarity with actual emergency rooms/hospitals/relevant statistics tell me, how often are the paddles used? What percentage of the time that they are used do they actually restart the heart? How many applications does it take? What kind of voltage is being applied across the patients chest? What's the restart mechanism - why does applying a voltage across the heart restart it and not totally mess it up in some other way? What would happen if you used the paddles on a healthy person?

Morbid curiosity wants to know :-)

[psychobunny]

Using "the paddles" is called defibrillation.
It does not restart the heart.
Often, when the heart fails, it goes into a quick quivering called ventricular fibrillation.
The goal of defibrillation is to stop this rapid fibrillation so that the normal beat can restart.
Therefore, technically, applying a shock is designed to STOP the heart so that the natural pacemaker can take over.
Think of it like a short circuit that you are breaking and hoping it resets to normal.
Shocking a person with a normal heart rhythm stops their heart and can kill them if it doesn't restart again. This is why you hear them shout "clear". You are supposed to make sure that nobody is in contact with the patient so that they don't get a shock (you also have to check that people are clear-on television they often just shout it without actually clearing people).
The electricity used for external defibrillation is from 100-300 Joules. Lower doses are uses to convert from rhythms that are considered less stable and therfore break more easily. Much lower does are used during surgery when the chest is open and the paddles can be applied directly to the heart.
Success rates vary widely. The best success is when you have a person who develops a witnessed abnormal rhythm and the defibrillators can be used immediately. The last statistics I saw gave about a 4% success rate overall.

[Kobal2]

Disclaimer : IANAD.
However, the obvious flaw in the question (and the medical dramas) is that the paddles don't restart hearts. They're called defibrillators, as in "device used to stop fibrillation".

Cardiac fibrillation is the opposite of a flatline : when the heart beats so fast or so arythmically that it doesn't pump blood anymore. This is due to the heart's electrical input going haywire, which happens for a variety of reasons. The paddles' role is to apply one big electrical surge to stop the heart for a short time in order to "reboot" it. So how it really should go is : bidibidibidibidi *BAMF* beep...beep...beep.
And of course, contrary to what you see on any medical show ever, you never ever shock a flatline, because stopping a stopped heart is redundant. IIRC, the only way to "cure" a full on cardiac arrest is CPR or cracking the chest open and massaging the heart directly after pumping it full of adrenaline. That is, of course, assuming the cause of the cardiac arrest has been dealt with in the first place. But as a general rule, a stopped heart is bad news

As for what kind of voltage the paddles deliver, a quick Google search gives me "three shocks, ranging from 200 to 1700V". And finally, as for what happens when you shock a healthy person, I would guess : the same thing that happens when said healthy person puts her fingers in a wall socket or gets tased : burns, a big and possibly fatal shock to the heart, horrible pain and involuntary muscle spasms, that kind of thing.

ETA : is it ninja day ?

[VunderBob]

BIG nit to pick: medical dramas often portray the defibrillator being used on a flatline patient successfully. The odds of a successful cardioversion from asystole (flatline) are exactly 0. When the heart doesn't beat, you're dead.

The odd of recovering from ventricular fibrillation given a witnessed arrest, prompt CPR, and defibrillation are about 25%, in the field. I don't know that figure for the event in a clinical setting, but I'd SWAG it at 33%, being generous.

I speak as an EMT.

[Machine Elf]

Originally Posted by psychobunny

Shocking a person with a normal heart rhythm stops their heart and can kill them if it doesn't restart again. This is why you hear them shout "clear". You are supposed to make sure that nobody is in contact with the patient so that they don't get a shock (you also have to check that people are clear-on television they often just shout it without actually clearing people).

There was a case a few years ago involving three EMT's in an ambulance: driver, passenger, and a third EMT in the back of the van. The third EMT was screwing around with the defib device; he snuck forward and deliberately shocked the passenger as a joke. Killed her.

[VunderBob]

Originally Posted by Joe Frickin Friday

There was a case a few years ago involving three EMT's in an ambulance: driver, passenger, and a third EMT in the back of the van. The third EMT was screwing around with the defib device; he snuck forward and deliberately shocked the passenger as a joke. Killed her.

He did it to his partner, and was convicted of voluntary manslaughter for it. That particular story is used as a teaching point in just about every certification, CPR, and Advanced Cardiac Life Support class ever since.

[Earl Snake-Hips Tucker]

Having said all that, though, how do they get non-beating transplanted hearts to start up?

[VunderBob]

Originally Posted by Earl Snake-Hips Tucker

Having said all that, though, how do they get non-beating transplanted hearts to start up?

Transplanted hearts are beating when they go in. Well, quivering may be closer to the truth, but they do have self-generated electrical activity happening. The last thing a surgeon does before turning off the heart-lung machine and closing up is to shock the new heart to establish (near-)sinous rhythm.

[Sigene]

Originally Posted by VunderBob

He did it to his partner, and was convicted of voluntary manslaughter for it. That particular story is used as a teaching point in just about every certification, CPR, and Advanced Cardiac Life Support class ever since.

This sounds like one of those Urban Legends. Everyone knows its true; its taught in every certification class.

Is it really true? Is there something more substantial than; "My instructor told me this."?


I'm not being snipey; it just has all of those classic hallmarks of "everyone knows it happened" but no one can seem to find an original source. I love those things.

[muldoonthief]

Originally Posted by Sigene

This sounds like one of those Urban Legends. Everyone knows its true; its taught in every certification class.

Is it really true? Is there something more substantial than; "My instructor told me this."?


I'm not being snipey; it just has all of those classic hallmarks of "everyone knows it happened" but no one can seem to find an original source. I love those things.

Googling "EMT defibrillator manslaughter" leads to plenty of stories about the case. Here's one.

And here's a Pit thread about it too.

[Bill Door]

Those wall hung automatic defibrillators designed to be used by untrained personnel have a feature that prevents the shock from being delivered if the heart is in normal rhythm. Are they good enough to distinguish between ventricular fibrillation and atrial? I've got atrial fibrillation, which, if you have a cardiac arrythmia, is the most benign kind to have. A shock to my heart is probably not going to do me any good, and it might kill me. Maybe I should get a medic alert bracelet.

[VunderBob]

Originally Posted by Bill Door

Those wall hung automatic defibrillators designed to be used by untrained personnel have a feature that prevents the shock from being delivered if the heart is in normal rhythm. Are they good enough to distinguish between ventricular fibrillation and atrial? I've got atrial fibrillation, which, if you have a cardiac arrythmia, is the most benign kind to have. A shock to my heart is probably not going to do me any good, and it might kill me. Maybe I should get a medic alert bracelet.

Yes, an SED will distinguish between atrial and ventricular fibrillation. You should have a medic-alert for that. Period.

[robby]

Originally Posted by VunderBob

He did it to his partner, and was convicted of voluntary manslaughter for it. That particular story is used as a teaching point in just about every certification, CPR, and Advanced Cardiac Life Support class ever since.

As stated in the NYTimes article, he was convicted of involuntary manslaughter.

More details of the incident here:
http://www.bookofjoe.com/2006/01/behindthemedspe_7.html

Here's the worst part:

Rhoton was in the front passenger seat of the ambulance, and driver Michael Coleman was heading south on U.S. 19 in Lebanon when Coleman heard Rhoton tell Martin not to touch her "with that," Bush said.

Coleman looked back to see Martin putting the paddles away.

But shortly afterward, Bush said, Coleman heard the "sound of a shock" and heard Rhoton yell: "Oh my God, Mike, he shocked me!"

Seconds later she stiffened and then went limp.

...Rhoton, who had been an EMT for one year, never regained consciousness.

She left behind two children, Christopher and Tamra, now 6 and 4.

I don't feel any sympathy for the guy. It was a malicious prank that, even if he hadn't killed her, would have felt much like sticking your finger into an electrical wall socket.

[VunderBob]

Originally Posted by VunderBob

Yes, an SED will distinguish between atrial and ventricular fibrillation. You should have a medic-alert for that. Period.

That's an AED, not SED. Old age, bad eyesight, and crappy typing skills don't mix well.

[St. Urho]

Originally Posted by VunderBob

Yes, an SED will distinguish between atrial and ventricular fibrillation. You should have a medic-alert for that. Period.

To elaborate at bit, atrial fibrillation and ventricular fibrillation look drastically different on an EKG tracing.

Atrial Fibrillation. Ventricular Fibrillation

[outlierrn]

ER nurse:

We mostly use adhesive patches that are multi-function, they can monitor, pace, and defibrillate, and only rarely use the actual paddles.

Cardiac cells are unique in that each cell will start to contract on its own. If you place a single cell in a growth medium it with begin to contract rhythmically without any incoming signal.

In ventricular fibrillation, all the cells of the ventricles are contracting (depolarizing) randomly. Without a coordinated contraction, no blood is being ejected. When you shock someone, the electrical jolt causes every cell that isn't actively depolarizing to do so immediately. Then we cross our fingers, and hope that the cells will begin contracting in unison again instead of at cross purposes. Sometimes it works, especially if we've restored oxygenated blood flow to the heart cells, and carried away CO2 and lactic acid with CPR. Since the purpose of defibrillation is to cause randomly contracting cells to contract all at once in the hope that they will continue to do so, it has NO VALUE in cases where the cells are no longer contracting. We NEVER shock asystole.

[Uncertain]

This is way off topic, but I've been wondering about it for a while. What's with all the "said", as in "said person"? I see that all the time here. Is it supposed to be mocking some style of writing? The only place I generally see it, other than the SDMB, is in legal writing.

[Earl Snake-Hips Tucker]

Well, it ain't exactly a mystery, and a cursory glance at a dictionary gives the basic info. Basically, I think it's because it's shorter than "aforementioned."

[Jodi]

Originally Posted by Uncertain

This is way off topic, but I've been wondering about it for a while. What's with all the "said", as in "said person"? I see that all the time here. Is it supposed to be mocking some style of writing? The only place I generally see it, other than the SDMB, is in legal writing.

There is significant cross-over from the legal style of writing to the language used in medical documentation. People who have to write reports recounting factual events -- especially if those reports may later be reviewed and/or used in a legal setting -- may be taught to write in such a fashion. Such is often the case in medical records that report negative events such as deaths. The other place you often see that sort of semi-stilted but still very clear language, is in law-enforcement reports ('said suspect" etc.).

[Uncertain]

Originally Posted by Earl Snake-Hips Tucker

Well, it ain't exactly a mystery, and a cursory glance at a dictionary gives the basic info. Basically, I think it's because it's shorter than "aforementioned."

You misunderstand. I have no problem understanding what is meant. I've used the construct myself, but only in legal documents, where it is necessary for precise legal meaning. In most places where it is used on the SDMB, "the" will do just fine, or "this" or "that" or the like (try substituting "the" in the two places where "said" is used this way in this thread, or "a" in the second case). I figured that either people are mocking some real or imagined style of writing, or they think that it's good writing because it's fancy. I rarely encounter it outside of the SDMB, but seem to encounter it here every day or so. Perhaps it's fairly arbitrarily caught on here, and people do it because they've seen other people do it.

[bouv]

Originally Posted by Bill Door

Those wall hung automatic defibrillators designed to be used by untrained personnel have a feature that prevents the shock from being delivered if the heart is in normal rhythm. Are they good enough to distinguish between ventricular fibrillation and atrial? I've got atrial fibrillation, which, if you have a cardiac arrythmia, is the most benign kind to have. A shock to my heart is probably not going to do me any good, and it might kill me. Maybe I should get a medic alert bracelet.

To elaborate on what Vunderbob, said, they are VERY good at distinguishing different arrhythmias. I had a job where I tested medical equipment, and that included both the wall-mounted AED (automated external defibrillator) and regular ol "paddle" defibs. I used a testing apparatus that did two things...it simulated a cardiac rhythm, and it measured the energy the defib actually discharged.

It was able to simulate v-tach, v-fib, a-fib, bradycardia, and even more complex rhythms, and not once did I ever encounter an AED that advised giving/gave a shock to a non-shockable rhythm.

[KlondikeGeoff]

Originally Posted by Bill Door

I've got atrial fibrillation, which, if you have a cardiac arrythmia, is the most benign kind to have. A shock to my heart is probably not going to do me any good, and it might kill me. Maybe I should get a medic alert bracelet.

Bill, I don't know how severe your A-fib is, but I strongly adivse getting a Medic Alert bracelet or necklace. As you probably know, should an attack last for a few days, it can be dangerous as it may cause blood clots that can be life threatening.

I've had it for years and not so long ago, it began to be very severe, with bouts evey day or so lasting 12-18 hours, with tachycardia of 180 beats or so. Twice was rushed to ER and admitted to the hospital. I had a pacemaker installed. They tried a couple of powerful drugs that not only had severe side effects, but did not do much to help.

Then, about a year ago I was started on a med called Rythmol, which has stopped any attacks of a-fib for more than a year, with no side effects at all. You might want to ask your doc about that.