Sun Nov 29 2020

REM fault will not clear, wrong return cable? Veterinary use

We purchased a Valleylab Force Triad from Avante Surgical a couple months ago. Our requests for help to Avante have went unanswered. The patient return electrode is a stainless pad style, not a split pad style. With the split pad, I understand that the REM system is measuring resistance between the pads to determine if there is good patient contact prior to initiating power output, as a safety measure to reduce burns. With the solid pad, there can be no such measurement. I see different connection wires listed for solid pads vs split pads. It appears from pictures, that the wires for solid pads are simply a modified split pad cable that have had a resistor soldered in line on each monitoring wire, which would trick the REM system in to believing there is good patient contact. Is it a reasonable to believe that we have been shipped the wrong cord for our solid paddle. That is, a measurement of the resistance of each wire, to show less than 5 ohms, is indicative of a cable intended for a split paddle.

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Mon Nov 30 2020Reply from EvgenyP
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Hello,

Your description is quite correct. We used to use those stainless-steel pads many years ago along with some ORs where they still have been using them currently for many years. I happened to see them come in two sizes. Let say large ones for high power for general surgeries and small ones for low power, e.g. for ENT. There are only three things which are very important - you have to make sure:

1st - the patient's skin is properly shaved;

2nd - there is a proper conductive layer (saline-wet tissue or conductive gel) in between the pad and the skin;

3d - the pad is properly pressed against the skin across all the pad's area.

Otherwise the patient's skin may be burnt. I doubt there were any resistors inside the cords as I had to unscrew and resolder them many times and did not see anything except copper wires.

Regards.


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Tue Dec 01 2020Reply from JacobR
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Well, without the resistors in line, it would not work.  

The solid electrode had a resistance of 0.2 ohm across the leads.  The second I put a 10 ohm resistor across the leads, I was able to get the REM alarm to go green, as it should.  And using two 5 ohm resistors inline, to the stainless electrode, I was able to simulate cut and coag using some moist dog food.  

Official diagnosis from the medtronic rep is that we were sent the wrong electrode/wire, and these units are no longer compatible with solid stainless steel electrodes. Single use electrodes must be used.  

Granted, we've been using a stainless steel non-REM electrode with monopolar cutting mode for years, at the same current density...but I understand their reasoning. 


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Tue Dec 01 2020Reply from jamesgilber
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The steel pads worked for Force FX and earlier generations of Vallelab ESU's, but I can confirm that starting with ForceTriad and the newer generation of Medtronic ESU's that there must be at least 10 ohms between the pads as described. This is in keeping with the latest FDA and International regulations regarding prevention of patient burns (see IEC 60601-2-2).


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Tue Dec 01 2020Reply from EvgenyP
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Hello,

In my experience those were also earlier generation Valleylab - Force 1 or 2 ECUs used in monopolar Coag/Cut modes. As for the newer generation of ESUs, I have never tried those with stainless pads.

Re “moist dog food” I would not advise to use it, as most often it is not made of meat at all. Sorry for the dogs.

I prefer wet plain soap or fresh meat.  

Regards.


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