A great question came through the website this week. The question went something like this: “There is confusion around the need to turn off oxygen during defibrillation or cardioversion. I’ve been told by a few FACEMS and Anaesthetists that it’s a myth and there has never been a spark explosion. Is that true?”
Just for you, I went all mythbusters, opened the lab and got to work……
The reality is that there are at most 5 case reports in the literature where there has been fire reported in oxygen rich environments. These all involved the old ‘paddles’. There have been no reports where adhesive paddles are used.
Here’s the theory:
The space around the patient is enriched with oxygen. If there is an electric arc produced during defibrillation, it ignites the patient’s body hair, moving very rapidly as a ‘front’, over the patient from hair to hair in a phenomenon described as ‘surface fibre flame propagation’. There is no burning of the patient’s skin, but when the ‘front’ meets bedding or clothes it can ignite them.
It is therefore important that if the old paddles are being used, that there is very good contact with the body surface. There must also not be any other metallic surfaces, such as ECG ‘dots’ near either paddles, or adhesive pads as they may cause an arc.
There is no issue with intubated patients and consensus is, that if you stand behind the patient and hold the bag about 1 meter away, there is no problem.
What do I do?
When I’m working in a resus situation, I believe that my resuscitation cubicle is large enough that there is dilution of oxygen. I also believe that the commotion around the patient is such that there is no oxygen layer around the patient. This is all interrupted by the turbulent flow occurring due to movement. As I use adhesive pads for my defibrillation and I monitor through them, I do not consider it an issue. When someone is about to defibrillate, I don’t turn oxygen off at the wall, but step bag and hold the bag-valve-mask away from the patient.
So as the myth busters say, it’s plausible, but in the resus cubicle of today with adhesive pads, not likely. So its…….
I hope that helped. Loved the question.