BLS Defibrillation: Are We Doing Enough?

BLS Defibrillation: Are We Doing Enough?

Jul 23, 2014

Recently, on the Resuscitation Facebook group, a discussion started regarding time on chest, time off chest, and the safety of defibrillation with active CPR being performed by a rescuer.   While the core of the debate and the reasons behind why and why not one would voluntarily subject themselves to an electrical shock is one that really needs more research to validate, it became clear that reducing the peri-shock pause (the time with no CPR prior to and immediately after defibrillation) could actually make the concept of receiving said shock a non-factor.

The discussion quickly turned to how long five seconds was, and how long three seconds was, and how with proper training and practice, a shock could almost be delivered on an upstroke with little to no pause in CPR.  It goes without saying that time on chest is vital for cardiac arrest survival.  Pit crew CPR teaches us some techniques to best deliver effective emergency responder CPR, but I feel like we can do better.

What about the other lengthy hands off time in the pre-shock period?  I am talking, of course, about the time that it takes an AED specifically to analyze the heart rhythm of a patient in cardiac arrest.  Usual analyze time for a monitor in my experience has been around 5-7 seconds depending on the model.  Once analysis is complete, many AED’s continue to announce “Stand Clear!” and start “spooling up” to their preset energy setting to prepare for a shock.  When it comes to dealing with the general public, this is, in my opinion, appropriate.  I do not expect some “Average Joe” who pulls an AED off a wall at the Mall of America to have the same ability to use it as someone who spent months (in some places a year) in an EMT class.  Public AED’s are a great thing, but why are we not putting better training and maybe simple EKG recognition skills in the hands of our BLS providers?

The first time I encountered an AED was in 1994.  It was a big deal for our town.  We had one for our two ambulance first aid squad and would switch it back and forth week to week depending on which truck was “first out” during that particular week.  There was no AED in the two police cars in town.  With our 5-7 minute “turnout time” we were expected to be the bridge until the paramedics made the five mile treck from the hospital to our little Jersey Shore town.

Twenty years ago (my god, it’s been twenty years) that AED had a screen on it.  I had no idea what I was looking at back then, but with a glance at the monitor, I could see what rhythm the patient was in.  My personal interpretation had absolutely no influence on whether the patient got shocked or not, but it was there.

Those screens seemed to gradually go away.  I do, however, still see them occasionally and even on one occasion when I walked in while a patient was being analyzed, I said “oh yeah, they’re going to get shocked” when the monitor almost at the moment those words finished leaving my lips announced to the room, “no shock advised.”  We then hooked up our LP 12, took a second look, and made the decision to override the AED’s opinion and we shocked the patient.

So back to the whole purpose of this blog: why are we not putting better training and simple EKG recognition skills in the hands of our BLS providers?  Personally, the matrix for this seems like a simple one: V-Fib, V-Tach, and “other.”  If the rhythm on the AED is V-Fib or V-Tach, shock it.  If it is not, and the patient shows no signs of life, continue CPR.  There is no reason to go back to pulse checks driven by what is seen on the monitor.  The American Heart Association went away from pulse checks for many levels of providers for a reason, and based on recent evidence regarding the effects of doing CPR on a patient with a pulse, I am okay with that.  After the patient “settles” from a pause in compressions, that  quick look could be performed in two or three seconds by a well-trained provider further reducing the peri-shock pause, and increasing both the “hands on” time and chance of survival for the patient.

While I was developing this post, I went to the good old Google machine to look around for what I hoped would be some study to support everything that I have written here.  The only thing that I could find was a study for 1984 that recommended “rapid defibrillation” for patients over what was then referred to as “standard EMT and paramedic care.”  I did not see the full study, but you can check out the Abstract paragraph here.  Sadly, the modern evidence is not out there.

Personally though, I feel that it is worth a shot.  We are ramping up training for EMT’s so why not add this to it?  In many systems, EMTs are giving Aspirin to chest pain patients and carrying EPI Pens.  Heck, in other systems, BLS units are putting CPAP on patients, giving Albuterol nebulizer treatments to asthma patients, and even administering the “life-saving drug” Narcan!  While all of those (even Narcan. . . kinda) are beneficial, it has become clear that there is a big push, almost a national mission, to improve ROSC rates and cardiac arrest survival.  If even on a small scale for a study, I think that giving EMTs some simple training in the recognition of lethal cardiac rhythms could increase the effectiveness of defibrillation and increase the “hands on” time that we are getting with these cardiac arrest victims.

So what does everyone think?  Should we expand training a little bit and effectively give our EMTs a tool that is better than those that we are putting in the hands of the general public?  Let me know in the comments section below.



  1. Joel /

    In my system we’ve done away with auto rhythm analysis for both ALS and BLS providers, we also have a CPR artifact filter on our monitors that allows for “see through” rhythm analysis while compressions are being performed. These changes are a result of our participation in a variety of ROC cardiac arrest studies. Our peri-shock pause has decreased from an avg of 20 seconds to 5 seconds or less as a result.

    I can email you a couple of studies out medical director has published on the subject if you’d like. Just need an email address…


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