Yes I can see the possibility for an unwanted current to flow as two floating generators could be at different potentials. But I would suspect that it would be very small as a similar effect occurs with static electricity. Large differences in voltage can be achieved but the power behind such floating is usually quite small.
But with that said, this would only be my own opinion expressed for the benefit of this site. If I was asked for my opinion by a Trust what advice should be given to medical staff my answer would be different. I would suggest that only equipment that has been recommended to be used in this manner by the manufacturer should be use in these procedures. If the models in question did not mention this capability in their manuals I may try approaching the companies directly. Try giving a list of other diathermies that can be used like this and ask if their model could do the same, if not, why not? I may even drop the hint that if they were unwilling to provide a answer in writing that they were likely to loose the Trusts business with future purchases. The reason being the Trust would wish to have this capability as procedures of this kind are quite common in electro surgery. In my opinion if a manufacturer was unwilling to give a statement either way it would look very poor. After all if they don't understand the workings of their own equipment how can they claim safe operation!
Adrian.
