about Nxstage supplies and length of time on machine

[boswife]

So, if hubbys perscript is for 2 1/2 hours, will we have enough supplies and the option to go longer if we feel neccessary on some days, or is it regulated pretty tight.  I really like the short time, but keep hearing how longer is better.  Thanks 

[greg10]

Longer dialysis will result in better phosphorus and potassium control and prevent left ventricular heart mass enlargement (better for the heart) because of better fluid control.  This will allow the patient to eat more normally and take less binders (some could cut out phosphate binders all together; save money and less pills is always good), and have lesser risk of cardiovascular problems.

Generally a NxStage dialysis prescription is written for the volume of fluid (dialysate and ultrafiltration) and not time.  The cycler will calculate the time for you based on the known inputs.

To increase treatment time, you have two options:
1) Decrease Blood flow (Qb).
2) Decrease Flow fraction (FF).

New time = (Present parameters / Target parameters ) * Current time.

For example, if you decrease Qb from 500 to 400 (2.5 hours or 150 min for the 500 ml/min initial blood flow rate):

New time = 500/400 * 150 min  = 187.5 min.

For example, if you decrease  FF from 0.4 to 0.35:

New time = 0.4/0.35 * 150 min  = 171 min

All these information are in the package you received from your clinic instructors, under the small booklet from NxStage entitled 'Quick Reference Guide'.

Flow Fraction (FF) is a measure of how fast the dialysate plus net ultrafiltration (UF) is flowing against the filter membrane counter current to the blood flow rate.  The formula is:

FF = (Dialysate flow + Net UF) / Qb.

[MooseMom]

Oh jeez, this sounds so complicated...

[tyefly]

Yes   Greg10 has great information.....    You may as I did feel better going at a slower blood speed which will result in a longer time on the machine... and there are benifits to longer slower dialysis..... 

You will get just enough supplies for your percription which the Doctor and the clinic agree on.... So if they tell you to use 20 L .... and then you will run for roughly 2.5 hours at say 400 blood speed....  Since you dont have anymore than 20 L to use per day ... the only way you can increase you dialysis to feel better is to slow your blood speed down to say  350 or 370 and then you will run for a longer period of time and getter better results...   Or you will have to ask for more bags of dialysate and then by using more of that you will still run longer than the 2.5 hours....   I started doing 20 L for 2.5....after a few weeks  I noticed that I didnt feel as good as I did incenter...so I ask to go to 30 L and now I am running roughly 4 hours at 370 blood speed....

 I feel the best I have felt ... in a very long time..... I feel perfect almost all the time....its amazing what enough dialysis can give you ......   I think if a person doesnt not feel really good ... they are proabably not getting enough dialysis.......
just a thought......

[greg10]

Oh jeez, this sounds so complicated...

Not really.  The answer to boswife's question is basically if you want a longer treatment time, turn down your blood flow.  Most patients will do this with trial and error, dialing down the blood flow to suit time.  The flow fraction will also have to be in range of a reasonable number (i.e., not zero, usually near 0.35) in order to have the time calculation to come in properly (done by the cycler).

*One note of caution is that if you are going to do a longer treatment time, you have to compensate for blood clotting over time and you will need to have appropriate measures of anticoagulation such as a heparin pump delivering heparin over many hours.  Generally, a treatment of 2-4 hours can be performed with just an hourly IV push of heparin in using syringes, manually delivered in the post filter (air) port of the cartridge.

[boswife]

Wow!! great information here.  Will print out and have in my D file.  You guys are great, No, amazimg!!!!!!!!!!!   And i thank you!!

[vcarmody]

I personally find that running at a higher blood speed for my husband 450-500 works better then a slow blood speed (FF30).  We process more liters of blood at a higher blood speed and he always seems to feel better with more liters of blood processed rather then longer time on the machine.  We average about 3:15 minutes of treatment 5 times a week with and average of 90 to 95 liters of blood processed. When we run at a slower blood speed like 400 (FF30) he averages about 3:30 minutes with about 84 to 88 liters of blood being processed.  It seems when ever we process 88 liters or less he feels pretty crappy, achy and he vomits a lot. I think it is all trail and error and you have to find what works best for you.  I finally have it down for my husband and that is 25L at 30 FF at a blood flow of 450 to 500, the higher the blood flow the more liters processed and more liters processed the better he feels.  I'm sure that is not the case for everyone.   

[boswife]

Wow,, to think one day i'll understand all this..lol  I appreciate it soooooooo much and will return to in in the comming weeks :-)

[tyefly]

   I worry about high blood flow speeds and healthy fistulas....  I understand that with a higher blood flow speed you can develop damage to your fistula and then needing a fistulagram which can further damage your fistula in the long run.... but are often need to keep the fistula flowing....  with high blood flow speeds there is alot of vibrations in the vein or fistula which can cause problems...  Slower speeds are better for the long term health of the fistula and a larger quanity of dialysate is better dialysis....I am thinking that 30 L and a FF33 or 35 would be better.... just a thought.... I am not the pro here   maybe Bill   or Hemodoc  or Zach  can word it better....

   I think that with higher blood flow speeds you miss out on the middle molecules    like phosphorus and others which need a slower speed to come off in the filter....

[vcarmody]

My husband is lucky he has never had any issues at all with phosphorus and potassium they have never been bad and I think we are very lucky for that.  He don't even take phosphorous binders.