The "dangers" of defibrillation

Most clinicians have heard tales about defibrillator accidents, and for the most part that is all they are: tales (or urban legends). External defibrillation has been performed for over half a century, with untold millions of shocks delivered. After all that time and all those shocks, the total number of documented deaths or serious injuries to caregivers giving shocks to patients is—none. Zero. Nada. Is this because safety precautions have been scrupulously followed? Of course not. In the often chaotic setting of a code, anything that can go wrong will go wrong—at least occasionally. And yet the record shows that operating a defibrillator is extremely safe.

This is not to say that caregivers have not received mild shocks causing discomfort now and then. Many probably resulted from the use of messy conductive gel with hard paddles. When hard paddles are used at all these days, solid conductive pads are normally used for the skin/paddle interface. But the norm today is dual-function (for monitoring and defibrillation) hands-free, self adhesive pads. Recent research suggests that with these pads the chance of even a mild shock to the operator or bystanders is vanishingly small. There is even growing interest in the possibility of giving a shock without stopping chest compressions. [1-3] Giving a distinct “clear” order is still advisable, but don't make it an elaborate, time-consuming ritual.

What about dangers to patients? If the patient is truly pulseless, it is a stretch to maintain that even an “inappropriate” shock—that is, a shock for pulseless electrical activity (PEA) or asystole (despite what the AHA says; I'll address this in a later post)—would cause real harm. If the patient has an organized rhythm with a pulse and is shocked, there is indeed a chance (around 5%) of causing VF; elective cardioversions are “synchronized” with an organized cardiac rhythm to prevent this possibility by avoiding shock delivery on the vulnerable part of the cardiac cycle. There have been a few reports of attempted cardioversions accidentally causing VF because the shocks were not synchronized. However, those cases are not relevant to emergency defibrillation for cardiac arrest.

Finally, I can't resist referencing one of my favorite movie scenes, which illustrates an extremely unlikely danger to the operator in defibrillating a victim--if the "victim" happens to be a malevolent, shape-shifting alien that has taken on the form of a human being. It's from the 1982 John Carpenter film "The Thing" (warning: this scene is extremely gory and gross). Of course, this isn't real; you can tell because the placement of the paddles is all wrong: http://www.youtube.com/watch?v=JjIXwkX1e48.

1. http://www.resuscitationjournal.com/article/S0300-9572%2809%2900014-8/abstract
2. http://www.resuscitationjournal.com/article/S0300-9572%2811%2900635-6/abstract
3. Perkins GD, Lockey AS. Defibrillation--Safety versus efficacy. Resuscitation. 2008;79(1):1-3.