minimum UFpossible?

If you are writing policies a good place to start would be the guidelines that are set by the machines manufacturers. I usually set for 500. This balances out the rinseback without adding fluid to the patient (700 if they are getting meds)

Hello- have you checked info on the machines & filters you are using? I do know that our machines have a setting for "High Flux" which increases the default minimum UF from 70 to 300, and we recently changed our filters to ones that have high flux capacity (we are not using this feature at present). This is info from the Fresenius Troubleshooting guide that came with our machines. Good luck!

Agree with above, check your machine and dialyzer maufacturer's standards.

300 ml/min is common min UF.

As you mentioned/alluded to, min UF is there as a minimum negative pressure safegaurd against backflow of dialysate across the membrane.

But where is this written? Even when I ask the biomed guys, they say that with the current machines, there is no possibility of backflow.

Granted I've only been doing this 5 1/2 years but we run zero UF multiple times/day in multiple units without any problem.

Agreed. Just because it's "the way we've always done it" doesn't mean it's (still) true.

Thanks for giving me something to look into this week. :)

Hi guys!

I would also love to know the answer to this ...we set out machines to 300 per hr also and its because its the way its always been done...to prevent backfiltration. I would think with the technological advances, our machines would prevent anything that would pose any harm to the patient...hope we get some responses! what machines do you use? also, I heard this applies with only the high-flux dialyzers..

The Fresenius rep told us that this came about due to the old machines and dialyzers. The techs from Fresenius were getting calls constantly due to pressure problems. They found that by setting the min. UF to 300, they did not have the problems and the calls decreased. She stated that it was never about backflow. She said backflow was just the reason given as to why it was done. Now, with the high flux the pressure problems have went away, but the myth of the backflow continues.

According to the Fresenius rep, there is no chance of backflow across the membrane even at zero UF.

However, the manufacture's recommendation still states 300 as the minimum. Fresenius is not willing to change that. Go figure?

Agreed.  I worked for one company for many years and never exp this, switch to a smaller company and all of the sudden "min 300 UFR?!" I never had an issue running with a UFR of 30 min and/or no uf if necessary. I have read the instruction sheet on the optiflux and although there is a max ufr there is no minimum.  I have looked at the century old manual and it states that is the min programmable ufr it doesn't state that it is the required rate.  So it appears that some people ran with that information whereas others have moved forward. 

In my training at Fresenius I was informed the reason is that their research has shown it's the minimum UF rate at which dialysis is efficient. In other words, you need that much fluid moving across the membrane to most effectively move solutes across the membrane. As one of the processes is convection, where solutes are dragged across the membrane with fluid if you recall, this makes sense to me.