Vertical from defibrillation

Question

I'm a library employee and just had to take a 1-hour CPR training this morning on how to properly do chest compressions and use the defibrillator.

The instructor said that you stand back when the defibrillation happens because the shock is so strong that if it gets you it will knock you down, and that indeed the person being defibrillated will convulse so violently that their entire body will come up off the ground and land hard. I had a difficult time with this, asking, "Leave them to hit their head hard on the ground when they land? Couldn't that cause significant damage?". She said there's a principal of "life vs limb" and that you weigh the upside of keeping them alive against the downside of damaging a limb, and you choose to keep them alive.

I felt like "limb" was not quite fair to describe the neck and head. But she seemed satisfied with her answer and hurried the class on.

Wikipedia says

in movies, television, video games and other fictional media [defibrillation] is often exaggerated, with the defibrillator inducing a sudden, violent jerk or convulsion by the patient; in reality, although the muscles may contract, such dramatic patient presentation is rare

But she is CPR certified and said she has been doing this for 16 years.

1. Is there really a vertical jump off the ground when being defibrillated?
2. If so, are cranial damages not really that severe when it happens?

Answer 1

I doubt your instructor has ever used a defibrillator or even seen one used. That was a huge exaggeration and Wikipedia is right.

Shocks from an automated defibrillator are delivered in three levels of power. Depending on the type of defibrillator used, the first shock will typically be 120 or 200 joules (J), the second at 300 or 150 J, and the third at 360 or 200 J._example What these numbers mean and what monophasic vs. biphasic means are irrelevant for the operator. What's important to know is that the lowest energy level will produce a noticeable convulsive jerk, but the patient will not come off the floor. The next level will produce a more pronounced jerk, and the third more pronounced still. Parts of the patient's body may come partially off the floor at the highest levels, but this image of a patient fully lifting off the ground high enough to be injured when they come down is a wild exaggeration. (Source: having personally performed and watched many defibrillations as an EMT.)

Youtube doesn't seem to have a good video of an actual defibrillation, but they do have several videos of a cardioversion, which is defibrillation's close cousin. What this video shows is a patient being cardioverted with 100 J of power, which is the first shock level a defibrillator would deliver. As you can see, he barely twitches (ignore the groan and arm movements - your patient won't be awake like he is). This is the same thing you'll see if you defibrillate a patient at the first shock level. The third level will be more pronounced, but they're not going to come off the floor.

However, your instructor is correct about "life before limb." If the patient bonks their head on the floor from a shock, that's the absolute least of their problems. And if you're doing CPR properly, you will probably break some ribs, especially if they're old and frail. That's okay too. If they eventually wake up in pain from the knot on their head and the ribs you broke, they had a very good day and you did a good job.