Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

The Circulation Improving Resuscitation Care Trial (CIRC)

We are still waiting for the publication of CIRC (Circulation Improving Resuscitation Care Trial), but the authors are out talking about it at NAEMSP and Gathering of Eagles.[1]

There are a couple of things that seem curious about the slides for the presentations. I have not seen either presentation.

M CPR = Manual. iA CPR = AutoPulse.
The larger circles are from the presentation. The underline and the smaller circles are mine.

The large variations shows inconsistency. That inconsistency is larger with the AutoPulse. Why? Once it is turned on, it should not need to be stopped for defibrillation.

Epinephrine and ventilations are unknown variables that have not been controlled for.

Then there is the problem of what they considered High Quality CPR –

Embarrassed by all of those extra bodies on scene?

Try the Pit Crew method of CPR. They will be running in so many different directions that people will assume that crew members must be doing something important!

This is just high activity CPR for the people with ADHD (Attention Deficit Hyperactivity Disorder), or a union trying to justify hiring more people.

There is no evidence that this attempt at high quality CPR improves survival over compression-only CPR.

If unnecessary ventilations are interrupting, or interfering with, chest compressions, the ventilations are only detracting from quality.

The fraction of AutoPulse compression time is better in the second 10 minutes, but when compressions are most important is during the first few minutes of compressions.

The lower the chance of survival, the better the AutoPulse performs?

89.2 compressions per minute with manual CPR, but only 66.3 compressions per minute with the compression machine. The AutoPulse only does compressions. What is it doing the rest of the time?

The problem may be that there are delays in hooking up the machine.

Not only is it not needed in the initial resuscitation, it seems to interfere with the initial compressions.

When are chest compressions most important?

During the first few minutes.

When does the AutoPulse seem to interfere with compressions?

During the first few minutes. 😳

Witnessed VF/VT Arrests 
• Survival higher for iA-CPR if CPR fraction <78% 
• No survival difference with higher CPR fractions. 
• Example: CPR fraction 70% OR 3.4, 95% CI: 2–7.4[1]

The Subgroup Analysis does not make sense.

The lower the CPR fraction, the higher the odds of survival to discharge?

This is not impossible, but it does raise questions about the results.

A CPR fraction of 50% appears to be over 20 times more likely to produce survival to discharge than an 85% CPR fraction?

To continue with that line of reasoning, if we were to stop doing CPR completely, we could increase the survival to discharge by a factor of 50.

That would be an interesting marketing strategy.

Buy our machine, but don’t even turn it on for the best results. Just use it as a lucky charm.

Once this is published, we should be able to see more of the data and maybe see where these numbers come from. Maybe.


[1] CIRCular Arguments: Was It Win, Lose or Draw in the CIRC Auto-Pulse Trial?
David E. Persse, MD (Houston)
Gathering of Eagles 2012
Presentation in PDF format



  1. I do give Zoll credit for subjecting their device to peer review, even if they spin neutral to bad data into their favor. Manufacturers of the other devices have not put theirs under as much scruitiny. I pressed a sales rep for one of those other devices about this, and his response was easily detected with Bryan Bledsoe’s Baloney Detection Kit:


    I like one of those other devices more than the Autopulse. In theory it works much better than manual CPR. I had one good experience with it, but not good enough for the patient to walk out of the hospital after it was turned off. I wish it’s manufacturer would publish some peer reviewed data about it for comparison..

  2. You can hate on the pit crew concept all day long, Tim. But having adequate rescuers on the scene matters a lot if you want to do a good job with sudden cardiac arrest. We looked at all the best EMS systems in the nation, with the highest survival rates, and they sent 7-12 people on the first alarm. In my system we send the closest ambulance, two engines and a battalion chief. You think you can do better with fewer rescuers? Prove it.


  1. […] Results of the “CIRC” Trial are now undergoing scrutiny having been presented at various […]