filtration fraction change?

[jelost]

I have been on home memo for 4 years. I got a new nurse about five months ago that is when my kt/v (for some reason) went down. She changed my filtration fraction from 35 to 40. Wouldn't that give me less of a good (clean) treatment? Would my time change? I run at 500 for 2 1/2 hours five days a week 20 liters. I start the new ff40 tomorrow.

[cdwbrooklyn]

No.  The higher the more your blood get clean and the more time you spend (maybe 15 more minutes).   It's a good thing. 

[jelost]

Thank you for reply. She also changed my liters to 25. She did not tell me that. She could have told me if I needed more time she told me it would be less time 

[Bill Peckham]

No.  The higher the more your blood get clean and the more time you spend (maybe 15 more minutes).   It's a good thing. 

? The higher the FF the faster the dialysate goes, the shorter the run. If you increase the amount of dialysate you're using 25% I would say you're coming out ahead but if you raise FF and keep the amount of dialysate the same you are getting >less< clearance.


EDITED TO ADD: In rough terms the FF is the rate of dialysate flow as a percentage of the rate of blood flow. If your blood flow is 500 then at a FF of 35 your dialysate is going through the machine at a rate of 175cc/min or 10.5 liters/hour. At an FF of 40 the dialysate is going through the machine at 200cc/min or 12 liters/hour.

20 Liters at 10.5 an hour is about 1hour 54minutes; your actual run length is longer because the amount of fluid you're removing also effects run length (and all these calculations), but if you assume you're taking off the same amount of fluid then the 25 liter run at 40FF should take longer - about a 2h 5m base vs. the previous base of 1h 54m.

[jelost]

Thank you. You told me more than my nurse or doctor 

[Bill Peckham]

Here is Peter's more complete discussion of Filtration Fraction http://www.hemodoc.com/2011/04/understanding-the-nxstage-filtration-fraction.html