Does anyone know anything about requirements for lid interlocks on centrifuges? We’ve had a small centrifuge delivered for commissioning. The lid can be opened when it’s still running – though the power is turned off by the action of opening the lid. The supplier says a label warning users not to open the lid while it’s running is sufficient. I may be being over cautious but it does not seem right to me.
Thanks
Graham

I wouldn't be happy accepting that either. See ECRI (1992).

There will be an IEC "Particular Requirements" Standard covering this (and no doubt someone will let us know the reference) which may talk about speed and diameter etc., but in my opinion, any modern (new) centrifuge should have a true "zero RPM" lid-locking system. That is, the interlock should keep the lid locked at all times during rotation (even during power failure) and require that the rotor be at rest before the lid can be unlocked.

Is this thing from a well-known manufacturer ... or some "back-door" *import?

See also this thread from the depths of the archives.

* Does it carry a CE mark?

Hi there. We have had this problem too. We had a rep come in to the hospital direct to the Breast Surgery team selling her centrifuge. It has no interlock, and the same excuse was given - the label is sufficient. She also tried to say that no other centrifuge was acceptable because the syringes being spun in the thing would be compromised (the sleeves they sit in could get contaminated).

Anyway, I asked our senior scientist in the Pathology team to help us, and his advice was that the centrifuge was unsuitable. I can do a bit of digging and see what machine we got in the end, but he was most supportive. He said they had had the same problem with the same company before, and the result had been the same; they bought a different machine.

The rep wasn't happy, but in my book that's just tough. She should have come through the right channels. Also, having been asked to bring the machine in through Medical Physics and agreeing to do so, she didn't. I caught her out by asking the senior ODA if he had seen her, and he said she was in his theatre as we spoke, with him using the machine... not his fault, and he was most upset that she was lying to him and using him to get her own way. If I had my way, she would now be banned from selling to our Trust.

Among all this, there were no decontamination instructions or documentation provided, which is essential.

The procedure this machine was being used to support was quite interesting. Apparently after cutting out the cancerous breast tissue and rebuilding the breast, the wounds heal best if you can inject some of the fat tissue under the stitched up skin. There must be no blood in the fat (hence using the centrifuge) but it gives a really good finish to what would otherwise be pretty grim scars. They heal flatter and cleaner. It is nice to think that such a small idea has such big benefits.

Bravo! Clare.

But why stop there? She should be banned from doing business across the whole NHS!

I've seen it a thousand times (both here and overseas) ... pretty faces (UK) or shiny suits ("out there") sneaking into the back corridors of the theatres etc. endeavouring to flog their [censored]. If the stuff was any good they would be proud to pass it by the biomed shop. I usually send them packing, with a flea in their ear, or worse (... better?).

And they are often breaking Trust policies...
If you look carefully at most procurement policies reps are only allowed in after having contacted the purchasing department and sought permission.*
In a previous job I asked our head of precurement to write to the company MD saying we would consider banning a rep if he continued sneaking in - no rep=no potential for any sales. It stopped him.
RoJo

* Though this is often subcontracted to Clinical Engineering etc by mutual agreement and to save the purchasing department all the hassle.

We have just such a policy. Unfortunately, Supplies is listed as their first point of contact, and they might not realise the full implications of the reps patter. This directive is so that reps cannot sell to the Trust while there is a contract in place, so Supplies is the best place on that score, but as to suitability and so forth - no.

We have used this clause to ban a rep before. It was only a temporary ban, but it made the point. Reps attempting to get advantageous information out of Trust staff by lying and claiming to have permission for that information when they expressly didn't - it does not go down well!

On the centrifuge point - we ended up with the Heraeus Labofuge 200 because it has a lid interlock. The rep didn't like it, so she was promoting a different one instead although the company sold both.

Graham has PM'ed me because we may have to share info that is best not public, but if you have similar troubles feel free to PM me.

Not going to "name and shame" then, Clare!

But (meanwhile) can you disclose if the Heraeus was purchased from the same company (that the rep worked for)?

And, what was it the rep didn't like:- the *Heraeus, or that her commission was being threatened?

* What other wonderful features could the other machine have had, I wonder?

I cannot name and shame here - it is definitely frowned upon in our department. I may be wrong but I thought that the machine eventually came from the same company. There was something about the procedure that meant certain companies were involved and it was all tied up together, such as research. Something like that, anyway.

I really cannot understand what the problem was with selling the Heraeus, as it happens. There was some suggestion that the syringes being spun fit too snugly into the rotor such that there was a contamination risk from the scrub nurse having to touch the retaining sleeve to get the things out. But as the rotor and sleeves would (surely?) have to be decontaminated after each procedure anyway, I could not comprehend why that was an issue.

By implication, the machine without the correct lid interlock allowed the syringes to fit less snugly so that the scrub nurse didn't have to get his bloody fingerprints all over the rotor. However, it also had no proper aerosol particulate protection, which the Labofuge 200 claims to have.

If you had seen the procedure in work as I did, there were several points where something might not necessarily be in ideal conditions - touching the sleeves or rotor was the least of their problems. There was a rack for the syringes and the trolley top that it was standing on that would also by that reasoning be a contamination hazard, but they are similarly cleaned so why just focus on the centrifuge? Part of the process involved tipping the serum and blood spun out of the fat onto a wad of paper towelling...! Yummy.

A rep from a (previously) reputable company tried to sell us a centrifuge like this a few years ago. We turned it down sharpish - we like having fingers, thanks. I'm amazed they think they can get away with it.

Sad to hear all of this. Gives sales reps a bad name.
Personally, our company has never touched machines without lid interlocks - no matter how small.

I think I know the company you are referring to Clare (think we all have dealings with them no matter where we are).

Yes ... but what does the Standard say?

Or, put another way, what's the point in having Standards if folk still don't follow them (just to save a buck or two, presumably)?

Geoff, I don't have access to the standards to check the exact wording, but I'd suggest the best standard to look at is IEC (or BS EN) 61010-2-020.

In any event, you must be sure that the machine will protect the user, even if the user is blind, drunk or blind drunk.

Lids cannot be allowed to be opened whilst the machine is spinning for obvious reasons, but there are other aspects of the standard where inference is given to certain safety considerations but the phraseing given is often very vague.

For instance, not all machines can boast sample containment in event of a disruption. If you are spinning high risk samples, even in small machines, a lid seal and motor seal are paramount to ensure the sample remains contained within the bowl.

You pays your money, you takes your choice...

Believe me I'm well aware of the problem(s), Anthony ... as I'm sure many of us are.

But what I'm pushing at here is (as I often am):- "Chapter and Verse"!

So, if the Standard (whatever it may be, and wherever it may be found) is, shall we say, lacking in any respect ... then let's take steps to get it corrected, clarified, re-written ... whatever.

Then perhaps people can be forced to stop palming off cheap [censored]* rubbish to our hospitals!

Meanwhile, Doom on vague phraseology! Especially in "official" documents produced at Public Expense:- Zero Tolerance there, as far as I'm concerned.

* Country of origin.

Hi all,

There are requirements for laboratory centrifuges. There are a few exceptions below, but most of the small units without lid locks fall foul in one way or another.

I will have to paraphrase the content as I can't directly cut and paste:

The lid must be lock while the rotor is spinning and remain locked until the rotor is less than 2 m/s.

If the lid can be opened it must meet all of the following

1) Have a catch to hold it shut
2) Switch off the motor when lid opened
3) No more than 3600RPM
4) Rotor Energy no more than 1kJ
5) No more than 2000xg
6) Rotor radius no more than 25cm
7) Off Switch
8) See through Rotor Cover
9) If you can open it at more than 2 m/s it must have a sticker

Source document?

Hi Geoff,

The document is BS EN 61010-2-020:2006 for Laboratory centrifuges.

Cheers
Colin

Thanks for that, Colin.

It took a bit of effort, but what I was trying to do was make clear (tease out, expose?) how weak the Standard actually is.

A "sticker" is not really what I had in mind when folk talked about a "lid interlock", sadly.

I completely agree, but most of the equipment out there will not meet the requirements, as they have to meet all the exceptions. You will find that they spin faster than 3600 RPM, produce more than 2000xg and 1kJ is not a very big rotor.

So what would your response be to Graham's original question?

I would first make sure that it meets all the exceptions, I suspect that it may spin faster than 3600 RPM check it on the data sheet or with a strobe. Is it new / secondhand, what size tubes, how many, is it fixed angle?

Thanks
Colin

To "cut to the chase", then ... it seems to me that 3600 RPM is the "catch" (oh yes, a pun indeed).

That is, if it spins at more than 3600 revs (as they all do, surely), then it needs a "proper" lid interlock.

I hope I'm right on this (and will make a correction if I'm giving out a "bum steer")!

It has to meet all of the points below to not have a lid lock that remains lock while it is spinning, and yes it's most likely to spin faster than 3600RPM.

Hope this helps, Graham can always call me here at work.

1) Have a catch to hold it shut
2) Switch off the motor when lid opened
3) No more than 3600RPM
4) Rotor Energy no more than 1kJ
5) No more than 2000xg
6) Rotor radius no more than 25cm
7) Off Switch
8) See through Rotor Cover
9) If you can open it at more than 2 m/s it must have a sticker

Our Main Plastics Surgeon requested a Centrifuge cost £2350 which on arrival for trial was non-compliant.ie the lid continues to rotate at 3000rpm when opened. The Surgeon said that this centrifuge was the standard equipment in other hospitals where he operated, he even asks the scrub nurse to slow the centrifuge quickly by placing a finger on the spinning tube holder.
[ The patients own body matter is spun and injected into the area to be re-built ]. I arranged a demo of an MSE Kestrel at £995. job done, fully compliant with beeps. Suggest that you EBME bods scrap all of these £2600 non-compliant units and buy the £995 Kestrel..ps the Surgeon is also happy

The MSE Kestrel works best with a capped 10 ml Terumo syringe in the centrifuge, the BD syringes are too loose. After spining and settling, the settled body matter in the 10 ml is injected via a joiner, into a 5 ml syringe, which is then used to inject into the patient

... and one of the few remaining bits of kit still made in England!