EBME Forums Forums Management Medical Equipment Management Potential Equalisation

Consider yourself smacked (cheeky whippersnapper ) I did not design the bloody things, however, i agree they should be CF but
their not...

Courtesy of gambro spec.

Seymour

Do you use isolation transformers with these devices then?

RL, you confuse me, why would you need isolation transformers? Millions of dollars where probably spent during the R&D of these devices, Gambro is a highly respected manufacturer of excellent machines, if they tell me it is protected against electrical shock according to classification B then who am I to argue.

Seymour

Class1B means the device passes the safety requirements for 1B and that makes me very happy for the company but I like to understand why sometimes. Yes of course Gambro are well known and respected Seymour but your statement made earlier about Class1B being totally isolated i.e. floating was incorrect; though I'm not being critcal, just wondering how the classification of a device like a renal dialysis machine can be class1B when the pressure-measurement devices (CVP) used with the renal kit are necessarily classified CF.

Just thinking about isolation regarding Renal kit especially; considering the transmission of fluids, internal to the machine, delivered to/from the patient and potential for leaks, etc. Considerations that have been commented on in this thread by others. Mustn't be a problem, otherwise we would hear about it, of course. Just my curious nature, I suppose....I will download the relevant standards from BSI at lunchtime, I think. Ta.

* the dialysate fluid and blood circuit are totally isolated

I will say it one more time so I am sure you have read it correctly

*the dialysate fluid and blood circuit are totally isolated

I refer to the machine's classification ... AGAIN I WOULD LIKE TO REMIND YOU SIR

My statement made earlier about Class1B being totally isolated Where did I say That..

If you want to debate my friend then I suggest you take the time to read my posts correctly instead of putting words in my mouth. Goodbye

Seymour :p

Actual Quote I was referring to was:

Initially I thought you may have meant 1BF but and made a typo error - after your comments later, I think maybe not. Read the post where you made comments about the heater being in contact with the fluid - I'm really not getting at you for a possible slip of the keyboard Seymour.

Just wondering about safety issues of kit I'm not familiar with. As for isolation of the dialysate and blood, I was talking electrical isolation. Even with my limited exposure I can appreciate the concern about physical/mechanical/electrical isolation of dialysate from blood. This is also evident in the standards you refer to yourself. I still don't understand why 1B - how old are the machines you refer to? What are the classifications of the latest generation of machines?

RL your not alone, this topic has undoubtedly got a few of us exercising the old-grey-matter.

One explanation may be that EN 60601-1-1:2001 Page 22 Table BBB.201 “Combinations of medical and non-medical equipment” requires an additional protective earth or separating transformer where (inside the patient environment) an item of medical and non-medical are in use (the bed or chair being non-medical?). This is also a requirement in the New Draft International Standard IEC6061-1, third edition, which has been out for consultation. The new draft further highlights the hazards of “Touch currents”. Dialysis companies may be reacting to this?

Out of interest, the New Draft further implies an additional protective earth on items of medical equipment (inside the patient environment) supplied via a multiple socket-outlet.

Bill

Thanks for that WOM - I hope you agree that 1B is not totally isolated (electrically) not as far as I'm concerned anyway.

As you say; combinations of electrical separation through isolation transformers and earthing, when absolutely necessary, are recommended I think. Yes, touch voltages need to be reduced to within the limits, so I suppose the best way is to "tie everything and anything down". What's the standard for electrical safety of chairs?

As John S says, the earthing of components of a system should be sufficient - it comes down to isolation really doesn't it? Especially for a single device i.e dialysis machine?

Thanks all. I've forwarded to Jim Lefever at MHRA for comments. I've got the Fresenius doc as a JPEG but am not allowed to attach to this post. I'll send to anyone for comments.

Gareth

gareth.murcutt@royalfree.nhs.uk

Now I am really confused, the original question as posed by Graham was
And I answered with regards to the "electrical" isolation of the blood and dialysate fluid which are two seperate fluid ciruits connected via a dialyser. What I was trying to say was the Blood and Dialysate FLUID circuits, and the patient are "Electrically Isolated from the dialysis machine".

Seymour