Question on clinic's Kt/V calculation

[caregivertech1]

Our Fresenius clinic uses an excel spreadsheet from NxStage to calculate monthly Kt/V. They use the same calculation without adjusting for male or female. At the same weight the volume for a female is at least 10% lower. If not corrected my wife's Kt/V would be significantly higher than what's being reported. Does anyone's clinic use separate calculations for male and female?  Our clinic uses the old "one size fits all".

[Rerun]

I'm not sure.  It has to do with volume of blood and time and speed?  Maybe call NxStage and try to get the spreadsheet.

Why would it matter between male and female?    

[obsidianom]

Our Fresenius clinic uses an excel spreadsheet from NxStage to calculate monthly Kt/V. They use the same calculation without adjusting for male or female. At the same weight the volume for a female is at least 10% lower. If not corrected my wife's Kt/V would be significantly higher than what's being reported. Does anyone's clinic use separate calculations for male and female?  Our clinic uses the old "one size fits all".

Does it really matter?  Kt/V is a bogus number anyway as it measures urea clearance which is fairly meaningless anyway. Many countries don't even use this as they realize that.

[caregivertech1]

The V in Kt/v is the volume of water in the body. A female at the same weight as a male will have around 10% or so less water volume. I did get a copy of NxStage's calculation and it does have a correction for gender.....but our clinic uses the same calc. for all, probably for a male but no one can tell me for sure. Kt/v maybe doesn't matter but unfortunately the NxStage dosing calculator uses a target Kt/V to recommend various dosages, and by the way also corrects for gender. So, when I enter say 3.0 and see that we're running at their recommended settings and keep getting 2.6 or so from the clinic calc., I wonder if in fact we're much higher. I know I'm really over my head here:)

[obsidianom]

The V in Kt/v is the volume of water in the body. A female at the same weight as a male will have around 10% or so less water volume. I did get a copy of NxStage's calculation and it does have a correction for gender.....but our clinic uses the same calc. for all, probably for a male but no one can tell me for sure. Kt/v maybe doesn't matter but unfortunately the NxStage dosing calculator uses a target Kt/V to recommend various dosages, and by the way also corrects for gender. So, when I enter say 3.0 and see that we're running at their recommended settings and keep getting 2.6 or so from the clinic calc., I wonder if in fact we're much higher. I know I'm really over my head here:)

Even though I don't care about KT/V I do notice my wifes matches the Nxstage predictions.  I aim for 3.0 and get 3.0. 
The Nxstage on line calculator works for my wife at least.  I set her KT/V at 3.0 and do what it recommends and get 3.0. 
What is your wifes weight and height and what do you run for days of the week and volume?  How much UF also ?
My wife weighs 55 kg and is 5 ft 2 .  We do 5 days per week at 30 liters for 3.5 hours. We run 330 blood speed . We process about 72 liters blood. We do virtually no UF.

[cassandra]

I've decided to not bother about any numbers anymore since my clinic still puts my Kt/V , and URR on my file without ever knowing what Volume I take of, nor how long I dialyse, as I'm at home. They base it all on the K as I sometimes do my bloodtests.
So my test is: do I feel okay? Than I am okay

       

   

[caregivertech1]

Thanks Cassadra, I was told by a Doc at the Cleveland Clinic he has to remind himself several times a day to treat the patient not the number. So how you feel is very important.
Dr. O my wife is 59kg, 65 inches, we do 5 days at 350 Qb and 30 liters with a time averaging 3.3 to 3.4. We take off probably  4 liters a week with blood volume 70 to 72.  She's really doing well at these settings. BTW these average times don't include the down time for the 30 min. Cycler auto checks. Kt/v has averaged 2.6. Thanks.

[PrimeTimer]

BTW these average times don't include the down time for the 30 min. Cycler auto checks. Kt/v has averaged 2.6. Thanks.

Ah yes...the Terrible Two's...my husband groans through every one of 'em...the mental anguish, not pain.

[PrimeTimer]

So my test is: do I feel okay? Than I am okay

       

   

    I LIKE your attitude!

[PrimeTimer]

Question: Will fewer dialysis treatments result in a lower KT/V result? I would think the answer is obvious but read on...

Here's the scenario: husband does home-hemo 5xweekly. He went on a trip for a few days. In four days, he had 1 in-center treatment opposed to 3 home sessions that he would have normally done. His KT/V result this month is the lowest it's ever been. Did not surprise us but the nurse called to say that we've got to redo his "pre" Tiger and Gold "post" blood tests so that they can calculate his KT/V again. Of course, we reminded her that he had less dialysis while away on a trip for a few days but she insisted that we redo his blood tests anyways. I can understand the concern but would think they'd wait to see what this next month's test results (KT/V) looks like (to see if it remains lower) before having an "OMG moment, his KT/V is the lowest it's ever been!"  Or...are they right to want the blood tests redone? I mean, in another week or so, it's going to be time for his monthly labs again anyways so... ? Anyway, hubby and I kind of expected that his KT/V would be affected by him not being dialyzed as often as usual but his center insists we redo these tests. Hhmm... 

[noahvale]

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[PrimeTimer]

Thanks, noahvale. I don't know what his pre/post BUN was but since they knew he had fewer treatments while away, I just thought they'd expect his KT/v to be lower. We will redo the tests and hopefully that will rule out any suspicion of trouble ahead. I sort of dreaded what his trip (fewer treatments) may do to him, not just labs but the affect on his body and overall health. He did come home with a little extra fluid onboard but a couple of home sessions took care of that. I think if he ever has to travel again, he should try to work it out to include as many treatments as allowed.

[PrimeTimer]

Question: Will fewer dialysis treatments result in a lower KT/V result? I would think the answer is obvious but read on...

Here's the scenario: husband does home-hemo 5xweekly. He went on a trip for a few days. In four days, he had 1 in-center treatment opposed to 3 home sessions that he would have normally done. His KT/V result this month is the lowest it's ever been. Did not surprise us but the nurse called to say that we've got to redo his "pre" Tiger and Gold "post" blood tests so that they can calculate his KT/V again. Of course, we reminded her that he had less dialysis while away on a trip for a few days but she insisted that we redo his blood tests anyways. I can understand the concern but would think they'd wait to see what this next month's test results (KT/V) looks like (to see if it remains lower) before having an "OMG moment, his KT/V is the lowest it's ever been!"  Or...are they right to want the blood tests redone? I mean, in another week or so, it's going to be time for his monthly labs again anyways so... ? Anyway, hubby and I kind of expected that his KT/V would be affected by him not being dialyzed as often as usual but his center insists we redo these tests. Hhmm...

To begin with, Kt/v is a discounted indicator of dialysis adequacy.  That said, yes, fewer treatments per week, especially if short time NxStage is his main treatment method and not getting in the same number of total hours will result in a lower Kt/v reading.  However, the better gauge of adequacy in treatment is the total number of hours dialyzed each week.  I go incenter only x3 weekly, but my dialysis prescription is for 6.0-6.5 hours sessions and kt/v runs between 2.75-3.1 each month.  As for overreaction from your clinic?  They might be more aggressive in wanting to determine if the low Kt/v was from his screwy schedule or something else like a recirculation problem with his fistula.  I know it means another trip to the clinic to drop off the bloodwork, but look at it this way, the clinic is trying to be on top of things. 

What were is pre and post BUN?  That plays into the kt/v formula.  Let's say pre was 80 and post was 20.  His kt/v would be higher than if pre was 70 and post 20 because more urea was cleared, but the resulting post BUN is the same in both instances.  Again, a reason why urea clearance is an inadequate gauge of good dialysis, it's easily removed.

I'd be interested in knowing what the redraw shows.

Results are back on his redraw. They recalculated (for NxStage cycler and 1 treatment in-center) his KT/V is at 2.32. Pre-BUN 65  Post-BUN 36. In addition to fewer treatments while he was away on a trip, some of the treatments we did at home were shorter due to storms, as we took him off the machine before power outages occurred. We avoid having to do manual rinsebacks if we can so that we don't risk losing/leaving blood in the cartridge circuit. Hopefully this next month will be a lot better for him. Anyways, thanks to our nurse, the redraw was worth it and we have a better picture of what is going on.   

[noahvale]

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[Simon Dog]

Yes, your husband's home hemo nurse just wanted to make sure there wasn't some underlying problem.

The clinics keep "score" on this sort of thing, so they were both looking out for his health as well as their statistics.   Despite the questionable nature of Kt/V, it's still the metric by which they keep score on how many of their patients get "adequate" dialysis.

You can ask the RN for the Excell spreadsheet (s)he uses to calculate Kt/V.   You'll need to enter treatement time; days/week; FF; dialysate volume, weight; UF, Pre/post BUN ... and the spreadsheet will spit out the Kt/V.   While you're at it, ask for on-line access to your labs so you can get the data at the same time your RN and MD does.

now it means another trip to the clinic to drop off the bloodwork, but look at it this way, the clinic is trying to be on top of things. 

As a home hemo patient, it probably means another call to Fedex or trip to a Fedex drop box.

We avoid having to do manual rinsebacks if we can so that we don't risk losing/leaving blood in the cartridge circuit.

Manual rinsebacks are not a big problem - I've done a few with no problem.   If you have any lack of confidence here, ask your home care RN to come to your house and babysit while you try one for practice.

[PrimeTimer]

I can perform the procedure but always worry about any blood, even residual, that may be left in the circuit. Especially when there are storms day after day, nite after nite. Every drop of blood is so precious (it all adds up) so that's my biggest worry. Of course we keep a watch on the weather and plan accordingly but storms can be very unpredictable and I don't do well with "unpredictable".   

[Simon Dog]

I can perform the procedure but always worry about any blood, even residual, that may be left in the circuit. Especially when there are storms day after day, nite after nite. Every drop of blood is so precious (it all adds up) so that's my biggest worry. Of course we keep a watch on the weather and plan accordingly but storms can be very unpredictable and I don't do well with "unpredictable".   

Manual rinseback (bag squeeze on NxStage) does not leave any more blood in the circuit that the normal automated procedure.

[PrimeTimer]

I can perform the procedure but always worry about any blood, even residual, that may be left in the circuit. Especially when there are storms day after day, nite after nite. Every drop of blood is so precious (it all adds up) so that's my biggest worry. Of course we keep a watch on the weather and plan accordingly but storms can be very unpredictable and I don't do well with "unpredictable".   

Manual rinseback (bag squeeze on NxStage) does not leave any more blood in the circuit that the normal automated procedure.

Thanks for giving me some assurance. Much appreciated!