The Skinny on Defibrillation - 150J, 200J, 300J or 360J? Biphasic or not? Waveform?

[Hockey]

It matters not what the manufacturer says. The docs that write the protocols want the shocks at 360j.

So... They get shocks at 360j.

In our area it says use the manufacturer rec settings

For Biphasic devices shock with energy levels following manufacturers’ recommendations (120 – 200 J). If unknown use the maximum available. For monophasic devices use 360 J.

 

[Jon]

PA State wide ALS protocols call for 360j for ALL shocks. I just took ACLS and used a Phillips monitor and that energy delivery was 150j.

It is pretty confusing. Honestly, no one really knows what the optimal dose is.

Actually, PA says 360J or max dose. With a Phillips MRx, that means 200J.

I talked with folks from Phillips and Physio at EMSToday. Physio says that their devices go to 360J, and the literature is leaning towards 360J all the time. The Phillips reps say that their research shows that a similar energy dose is delivered using 150J and their biphasic algorithm.

I'm not sure how much is science, and how much is hype (the defib equivalent of mine "goes to 11").

 

[Melclin]

The country our defibs were made in no longer exists.

I just put it in "H".

 

[NomadicMedic]

 

[18G]

Actually, PA says 360J or max dose. With a Phillips MRx, that means 200J.

I talked with folks from Phillips and Physio at EMSToday. Physio says that their devices go to 360J, and the literature is leaning towards 360J all the time. The Phillips reps say that their research shows that a similar energy dose is delivered using 150J and their biphasic algorithm.

I'm not sure how much is science, and how much is hype (the defib equivalent of mine "goes to 11").

My bad. Most EMS agencies around here use Lifepaks which means all shocks are at 360j.

 

[Moshi]

I'm sorry to bump this old topic but recently this topic has been discussed where I work and noone can really explain it.
I read this topic and links in it but I still don't understand much as it has lots of "heavy" scientific words.
So can someone explain this to me in a more easy and less complicated way?
English is not my native language so bear that in mind when you write as I will have to translate it to my language and explain to my colleagues.

Thanks!

 

[MasterIntubator]

Its a complicated subject, but maybe this will help you understand the differences:

Think of all this electrical mumbo jumbo in relation to a graph ( remember the X-Y plot graphs in basic math or algebra? ) You have a horizontal line which is zero. Anything above it is positive, everything below it is positive ( like ECGs and the isoelectric line ----- another analogy ).

Monophasic - when it delivers a shock, it is one way.... zaaap. All its energy is positive ( going above the zero line ). It goes up sharply, the slopes downward as it goes back to zero. It did not account for stuff in the way slowing it down ( resistance ). There is no balance, and this why it takes soooo much energy to make a shock somewhat effective.

BiPhasic ( Truncated version ) - Used by LP and Phillips and a few others. Originally it was used in implantable pacemaker/defib units in the before the 80s ( its not new technology ). This style of defib accounts for the resistance it encounters ( pts skin, mass, electrolyte gel contact and so forth ). When it shocks, it rapidly rises to the positive on the graph ( like turning on the stereo and someone left it on high - that sudden blast -), then quickly below the line to the negative. It is more balanced than monophasic, and more effective. Its a rougher style of biphasic and the waveform is a bit more unorganized than the second BiPhasic..... but it gets the job done well with little difference. Which is why Physio still recommends 200-300-360. Protocol dictates from there.

BiPhasic ( Rectilinear version ) - Zoll technology. They perfected the waveform and it does the same thing as truncated, just cleaner and more balanced with out the extra "spikes". It goes positive in a well controlled manner without a peaking spike, and rebounds in the negative nicely. Its like the "greener" version of defib ( yes, I had to go there ). And due to its well balanced shock, and its ability to adjust to the resistance/impedance ( which is a big word for stuff in the way slowing down the flow of electricity )... Zoll is very comfortable with 200J being effective.

Triphasic - Last I heard, this is still experimental. and has been since the 80's. But Phillips advises that it is far superior than Biphasic and one day may be on our band-aid buggies. This actually shocks twice in the same amount of time as Biphasic, rebounding twice as well... with less voltage and amperage.

Maybe one day we will reap the benefits of this technology.

 

[Moshi]

Thank you very much! A lot clearer now for me and my colleagues!

 

[Steveb]

I'm used to Zoll but here at work we have Lifepak 12's.

I was out playing with it and noticed when I went to change the energy setting, it said Biphasic. However...it allowed me to turn the energy up to 360j.


Why? What? Huh?

I have the manual but I can't really find anything about this

I belve LifePAk is now a verified vendor now check there Sub forum

 

[Christopher]

I'm used to Zoll but here at work we have Lifepak 12's.

I was out playing with it and noticed when I went to change the energy setting, it said Biphasic. However...it allowed me to turn the energy up to 360j.

Why? What? Huh?

I have the manual but I can't really find anything about this

Some good references for the Physio-Control ADAPTIV waveforms can be found in this PDF on the topic. It covers the internal technologies used and the relationship of the waveform to the physiological response in the myocardium. Plus it provides many excellent illustrations to help relate these concepts.

Zoll has a wonderful website dedicated to their rectilinear biphasic waveforms. It too contains a step-by-step explanation of the technology and the related physiology.

Philips has the least digestible website of the three major players, but it contains plenty of research on their SMART Biphasic waveform.

Really though, if you're looking for a high-level overview of the science (with illustrations) the Resuscitation Central site on defibrillation cannot be beat. It covers each of the major waveforms used in the field and how they compare technologically:

Both Physio Control and Philips use the biphasic truncated exponential (BTE) waveform originally developed for internal defibrillators, though they use different energy settings with the waveform. Physio Control uses what they term a "high energy" biphasic waveform, which they term ADAPTIV™ Biphasic. Physio Control energy settings go up to 360 joules of energy and they essentially distribute the voltage and current available over a wider range of energy settings. Additionally they vary the voltage and extend the duration of the shock in higher impedance patients.

I hope this helps!

 

[Physio Control]

I'm used to Zoll but here at work we have Lifepak 12's.

I was out playing with it and noticed when I went to change the energy setting, it said Biphasic. However...it allowed me to turn the energy up to 360j.


Why? What? Huh?

I have the manual but I can't really find anything about this

Physio-Control recently joined the EMTLife Forum as a member of the new Verified Vendor Program and came across this discussion. We wanted to offer some additional information that should help provide context.

When treating difficult-to-defibrillate patients, escalation of energy can be an important element of improved outcomes. Physio-Control products have been studied in more than twice as many cardiac arrest patients as all other manufacturers combined. The data shows that the only way to increase shock efficacy when lower-energy shocks fail is to increase energy. That’s why we offer the highest available energy—up to 360J.

Many factors contribute to successful defibrillation, including: 1.) the peak current of the waveform, 2.) how long the current is applied, and 3.) how the current is maintained throughout the shock. While peak current plays a role, it does not determine shock efficacy. Energy includes all three elements and has been shown to best describe the therapeutic dose delivered to the heart.

Consider that three clinical studies have compared biphasic waveforms used by Physio-Control (biphasic truncated) and Zoll (biphasic rectilinear) in synchronized cardioversion. The combined results show that, though Zoll’s waveform delivers higher levels of current, the waveforms are equally effective at 200J (96% efficacy).

Some concern was expressed earlier in the thread with regards to the use of 360J. Bear in mind that both the 2010 American Heart Association and European Resuscitation Council Guidelines recommend energy protocols in which the initial dose follows manufacturers’ recommendations (120–200J) and subsequent shocks given at an equivalent or higher dose. For reference, “Human studies have not demonstrated evidence of harm from any biphasic waveform defibrillation energy up to 360 J…” (American Heart Association Guidelines 2010; pg. S708).

Additionally, independent defibrillation studies support the AHA Guidelines. Two clinical trials using escalating energy protocols to 360J reported no measures of myocardial damage by enzymes, ECG changes or ejection fractions (Stiell I, et al).

1. A randomized comparison of fixed lower versus escalating higher energy levels for defibrillation in out-of-hospital cardiac arrest (Circulation, 2007; 115:1511-1517. Neal S, et al).
2. Comparison of the efficacy and safety of two biphasic defibrillator waveforms for the conversion of atrial fibrillation to sinus rhythm (American Journal of Cardiology, 2003; 92:810-14).

 

[Jon]

This was actually being talked about in another thread at the same time. I've merged the threads for the sake of simplicity. Other thread is all posts 3-1-2012 through 3-6-2012.

And this is my favorite part. Just saying.

 

[Trashtruck]

your medical director should review what kind of waveform you have and adjust as necessary. which is why AHA says "for biphasic, use manufacture recommended energy setting". 200 max for zoll, 200, 300, 360 for LP. due to the different waveform algorithm 200j from the zoll delivers about the same total energy as 360j for the LP. i am un familiar with the Phillips.

here is a similar research paper from zoll.

Hi,
We have LifePak 15's and we shock at 360J right off the bat per our medical director. Obviously, all subsequent shocks are 360.

 

[Farmer2DO]

zoll and physio-control use two different types of biphasic therapies, zoll is biphasic truncated waveform. physio-control uses biphasic rectolinear wavecorm. basicly what happens is zoll will apply a constatn 200j throughout the shock (approx. 10ms) while physio will deliver a peak of 200j then taper off, which is why they increase the current to a max of 360j, to increase this peak current.

Actually, it's Zoll that uses rectilinear and Phillips and LP use truncated exponential.

Here's where those calculus classes actually apply to something real. Remember the integral? If you integrate an equation from a to b, you get the area under the curve, from a to b.

On the graph, the x axis is time, and the y axis is current (amps). The theory is that it's the area under the curve that defibrillates, and all of them provide the same, more or less. The truncated exponential provides for a higher peak current, and there is concern for myocardial stunning, which is where rectilinear comes in. It doesn't peak as high, but holds it for a longer period. It uses capacitors that fire sequentially, rather than all at once. Personally, I think the rectinlinear waveform makes more sense (even though I HATE the Zoll monitors in general), but I'm far from an engineer.

http://www.resuscitationcentral.com/defibrillation/biphasic-waveform/

There's also the Gurvich waveform, which is described as quasi-sinusoidal, but I think that's only used in implanted defibrillators.

 

[MasterIntubator]

You speak words that excite me.