In response to recent confusion:
How can you tell the difference between Ultrasound Gel (used for ultrasound machines) and Electrode Gel (used for defibrillation)?
Answers after the break!
Why is this a problem? When someone extra ultrasound gel, you may delay an ultrasound scan for a few minutes.
In contrast, when electrode gel is removed from its proper location, the defibrillator can’t be used. Although we all feel ultrasound is important, it still hasn’t trumped early defibrillation in ACLS.
So why do you need gel to begin with? There are several reasons.
The gel serves to eliminate any air between the transducer and skin. The acoustic impedance (Z) of air is so different than that of the transducer that all of the sound energy would be lost before transmitting into the tissue. Gel (officially termed coupling gel) serves as a better medium to transmit the acoustic energy from the transducer into the body. It is designed to have an acoustic impedance which will be similar to body tissue and the transducer itself, limiting scatter and maximizing the amount of acoustic energy transmitted.
Related posts:
The article is not quite clear.
Two question are important:
1) Is it a problem to use ultrasound gel to defibrillate?
2) Is it a problem to use electrode gel to do ultrasound?
For question n2 I would answer that in my experience electrode gel gives a fair echographic imaging but is a little worse of gel designed for echo; when I have only electrode gel at hand I prefer to use just water instead of gel for better imaging. This is probably due to different Impedance of the electrode gel (Z).
For question n1 I don’t have an answer
Great questions! First, let me explain the reason for my post. Staff were taking defibrillator gel from the code carts and using it on the ultrasound machines. Very bad.
On to your questions:
Ultrasound gel is optimized for acoustic impedance, and electrode gel is designed to minimize electrical impedance. Practically speaking, both gels are aqueous solutions capable of transmitting either sound or electricity. As you’ve noted, water can serve as an ultrasound coupling agent in a pinch. Others have used surgical lubricant, lotion, and a host of other such liquids when “real” ultrasound coupling gel is unavailable.
With regards to defibrillation, ultrasound gel works pretty well.
I have not been able to find an ingredient list for any commercially available ultrasound or defibrillator gel.
For example, here is the only data I could find on Aquasonic’s Ultrasound gel:
* Acoustically correct for the broad range of frequencies used
* Completely aqueous, will not stain clothing or damage transducers
* Unique “can’t be copied” formula is hypoallergenic, bacteriostatic, non-sensitizing and non-irritating
* No formaldehyde
* Not a spermicide
So at least we learn that it isn’t a spermicide!