Cycler results

[fleo]

I use a Liberty PD cycler and work with Fresenius. My question is what are the variable that impact the UF results from a cycler session? On consecutive days, with diet and fluid consumption are the same, I get a UF result of 700 ml one day, then 2,000 ml. I've asked my PD and didn't get a good answer.

Thanks,

FLeo