Temperature Sensor, 9.1B Upgrade and Balance Chamber Calibration

[Annette Bull]

I don't wish to put the cat amongst the pigeons, but would like to know if we are the only people having issues!!

Is anyone having issues with low UF runs following the MHRA directed BBraun temperature sensor move, software 9.1B upgrade and balance chamber calibration? All our normal machines appear to be failing their UF runs post upgrade.

Upgraded HDF and CDF machines appear to be ok and come in within the 125 ml +/- 15 ml specification, but only just,  with them not taking as much fluid off as in their previous UF runs.

We have tried doing runs of every connotation, but with no success.

It has got to the point that we are unwilling to do the upgrade, as it takes a machine out of circulation as they are out of spec.

Any thoughts?

Annette

[david beesley]

Hi Annette

I  have completed at least 10 of these modifications at the Royal London, and have had no problems with correct UF removal.  this is a mixture of DF and HDF   machines.
I am sure you are, but Just a thought, are you doing a UF pump calibration before you do your balance chamber cals?    

David

[Annette Bull]

Sorry for the late response, I was waiting for permission from the website to reply.

We are doing everything according to the instructions. We have found that CDF and HDF machines tend to come in on the upgrade, but the majority of our standard machines are not falling within the UF specification.

Annette

[Andy Mosson]

We have done quite a lot of these upgrades and have had no UF problems. We have had problems with faulty thermistors - it seems they don't like being moved!

[Garry]

It's a bit of a mystery at the moment.  As Annette mentioned, though we are seeing a drop on all machines the effect is most pronounced on standard machines without hdf or cdf filter.  We have completed 10 standard machines (with about another 50 to go!).  Comparing average UF change from last PPM, over the last 3 years, we have seen an average UF error, on these 10 machines, of  <4ml.  Following upgrade we are seeing an average errors of much greater negative values.  With only a +/-15ml window  there is not much wiggle room.  We have also calibrated  a number of machines immediately before the upgrade and have seen similar drops in UF post upgrade, the only change being upgrade.  Engineers from Germany will visit next month so I'm hoping the reason is found even if it is to point out something very silly we are doing.  Currently continuing to upgrade HDF equipment with a hold on the standard machines until resolved.

Update:  Seems that the upgrade does introduce a small reduction in UF volume removed.  Our error was that the recorded UF runs had been performed on our equipment default dialysate flow of 700ml/min instead of the required 500ml/min.  Any deviation in the balance chamber was being magnified by the higher flow rate. Back to 500ml/min and all OK now.