Taking NxStage System One to the Max

By Peter Laird, MD

Since starting on the NxStage System One in June of 2009, I have continued to look for its maximum efficiency in my own personal treatments just as I did while doing self care incenter.  One of the frustrating aspects of using the NxStage machine is the lack of available medical studies on specific issues. The Nxstage literature base is quite incomplete at this time and many more studies need to be completed. Fortunately, we have a recent publication from Hemodialysis International that begins to answer some of these questions of how effective is the NxStage System One when compared to the standard incenter thrice weekly dialysis at the level of solute kinetics (thanks to RenalWEB for highlighting these articles). Solute kinetics with short-daily home hemodialysis using slow dialysate flow rate:

The weekly treatment time for the patients averaged 17.4 h/wk, a figure higher than the average weekly treatment time embraced by many US in-center dialysis units where a thrice-weekly regimen is practiced. The removal rates and clearance values in the present study should therefore be interpreted in the context of increased weekly dialysis time. While the low dialysate flow rate reduces urea removal, the increase in the frequency of the treatments improves it. In the case of phosphorus and β2M, increased dialysis time is more critical for their removal and compensates for the low dialysate volume.

In my own review prior to starting the NxStage System One last June, I noted that the relationship between NxStage dialysis flow rates and clearance is nearly linear until you go over a dialysate flow rate of 200 ml/min.  Most recommendations for the dosage of NxStage are based on the Filtration Fraction (FF) or percent dialysate flow rate compared to blood flow rate.  However, when looking at the actual flow rates instead of the FF, it is my belief that the recommended NxStage dosages are simply too low.  In my case, at 90 kg, the NxStage dosage recommendation is 20L with a FF of 35%.  In my training, I started on this dosage which I did not find adequate for improving my symptoms and my energy levels even though I did hit the targeted Kt/V of 0.5 with 20L.

When I went home, we started at 30L, FF 35% with my Kt/V improving to 0.77.  With a blood flow rate of 360 to minimize my venous and arterial pressures, the actual dialysate flow rate is 126 ml/minute completing treatment in 238 minutes (3 hours and 58 minutes).  My phosphorus (PO4) level increased by 30% from my usual incenter values on the 20L regimen despite continuing the same restrictive diet. Dr. Scott Rasgon likewise found this in his published data of NxStage users in their program at Kaiser Permanente Sunset medical center. Due to the concern of long term PO4 elevations and looking at the clearance charts for NxStage, I approached my nephrologist about going outside of standard NxStage parameters to maximize the effective volume of dialysate to see if I could improve my PO4 levels, which act like a middle molecule.  He agreed to increase my dosage to 40L of dialysate at a FF of 45% (162 ml/min dialysate flow rate) to keep the treatment time near the four hour level of my 30L treatments.  I was pleased to find my energy levels improved as well as increasing my spKt/V to 0.93, 86% higher than at my 20L dosage, and my PO4 levels returned to my pre-NxStage levels at 3.5 from the 4.6 level on the lower 20L dosage without any binders which I have not ever been on to date.

20L Time 158 minutes  FF 35%  (BFR 360/min - DFR 126/min) spKt/V- 0.5
30L Time 238 minutes  FF 35%  (BFR 360/min - DFR 126/min) spKt/V- 0.77
40L Time 246 minutes  FF 45%  (BFR 360/min - DFR 162/min) spKt/V- 0.93

NxStage dosing is supported by the Standardized Kt/V value of 2.0/week with in center thrice weekly dialysis per KDOQI standards.  The single pooled Kt/V (spKt/V) values are not linear which means you can’t simply add the daily values to obtain a weekly value.  The level of spKt/V of 0.5 comes from the fact that this will produce a Standard weekly Kt/V (stKt/V) of 2.1 which falls within the recommended KDOQI standards. Northwest Kidney Centers has set their weekly stKt/V at 2.5 (PDF link) which is also the standard weekly Kt/V goal of the Frequent Hemodialysis Network as well.

High-Frequency Hemodialysis: Rationale for Randomized Clinical Trials:

The target weekly or standard Kt/V for urea in the current frequent hemodialysis trials will be approximately 2.5 in the conventional thrice-weekly arm, 3.8 in the daily in-center hemodialysis arm, and 5.6 in the nocturnal arm.

I greatly appreciate the recent study from Hemodialysis International on the solute kinetics of the NxStage at standard recommended dosages.  However, I must question from my own personal experiences with the NxStage System One whether maximizing the efficiency of dialysate flow rates paradoxically reduces the maximum clearances at the patients level.  It is certainly a wonderful thing to watch numbers and efficiencies improve, but if it does not translate to maximum patient benefits then we should abandon this approach and look at maximizing total dialysate dosage for patients on the NxStage instead.  For an increase of dialysis time by over 30%, I gained an 86% increased spKt/V and ~25% reduction of my phosphorus levels by exceeding standard NxStage dosage recommendations as well as using a higher Filtration Fraction.  The theoretical loss of dialysate efficiency at higher dialysate flow rates and Filtration Fractions may be offset by a simple increase dialysis dosage that translates into higher urea, phosphorus and B2M kinetics as I found in my personal NxStage experiences.  This simply question has not yet been answered in the NxStage literature, but it needs to be considered.

How good can the NxStage machine be if taken to the max?  Indeed, optimal dialysis paradigms operate on the simple concept of maximizing frequency, time and clearances in standard machines.  It is time for investigators to explore this aspect of the NxStage System One noting urea, phosphorus and B2M clearances over a broader range of dialysate flow rates and Filtration Fractions which will allow higher total clearances comparable to standard incenter machines.  My own anecdotal experience suggests that there is significant room for improvement over standard NxStage dosage paradigms (PDF link) published to date that should be explored to eliminate the low clearance shortfall that has kept many nephrologists from recommending the NxStage to their patients despite the advantages of having a portable machine.  It is time to take the NxStage System One to the max.

Comments

[Miriam Lippel Blum]

Peter,
Thank you very much for sharing your experience and research findings. I will be passing along your observations to my nephrologist and his colleagues so that they may be even better informed when they write dialysis prescriptions for their NxStage dialyzors.

I'm glad you're doing well and getting the level of clearance you want.

Best wishes,
Miriam

[Kathy Heffner]

Thx Peter.....I have just started Nxstage I have noticed a reduction in my labs and I do not feel as well as I did incenter.... So this information helps me understand that I too need more dialysis and better dialysis....I hope to change my current prescription to help achieve a better results....Thx for sharing your results...

[Zach]

As T.R. would say, "Bully Peter, Bully!"

It's good to see someone question NxStage's "short daily" selling points.

Solutes that are time dependent, such as phosphorus and B2M need to be considered when Nephrologists write the hemodialysis prescription for people using NxStage.

One might feel great to do hemodialysis 5 or 6 days/week for only 2.5 hours, but in the long run (5 to 10 years down the road) we may find that such a prescription is less healthy than originally promoted by NxStage.

[Peter Laird, MD]

Dear Zach, Kathy and Miriam, the idea of optimal dialysis is part and parcel of the NxStage System One with the exception of taking the dosage to the highest degree possible. There focus is maximizing the efficiency of the dialysate. This is certainly a noble deed, yet, the fact that at the dialysate flow rates used with the NxStage, the curve is no where near the plateau that we see with in center machines. I believe that even though there may be a modest decline in the absolute efficiency of modestly higher dialysate flow rates, it declines at the same time the clearances are paradoxically still increasing and well below the plateau levels.

I believe that this is a fundamental flaw that limits the total dosage that could be attained at only modestly higher dosages and higher Filtration Fractions. It is my hope that those doing NxStage research might consider expanding the envelope to see if my own anecdotal findings could be generalized. At 90 kg, I simply found lower dosages inadequate and I did not feel as well as I did from Thursday through Sunday. Monday nights with headaches were always my dread while in center.

I am grateful for having NxStage at the dosages I currently use. I would hope that others would likewise have the opportunity to take their NxStage experience to the max. I appreciate centers such as NKC that engage a higher targeted Kt/V right from the start and seek to maximize time on dialysis and outcomes at the same point of time. Unfortunately, centers such as NKC are a rarity as I am sure Bill would testify gladly. Bill has likewise benefited greatly from a higher dosage of the NxStage System One and credits his nocturnal treatments with being able to do this blog. It is time for the patients to seek a maximum benefit from what ever renal replacement modality that they use understanding the simple optimal dialysis principle that more is better.

[Bill Peckham]

Time is the critical factor. You just can't get around it with flow rates. Sure, given the parameters of conventional dialysis, or a given treatment, high flow rates will give you higher clearances but still only through more time do you have access to the majority of fluid in the body.

The question that we don't know is if instead of going from 20L to 30L what would happen if you kept it at 20L and decreased FF so the treatment lasted for 238 minutes? I'm not sure we know.

[Peter Laird, MD]

Bill, I agree that the time factor has not been addressed well to date. Few centers are using the NxStage for nocturnal dialysis where that question could be best addressed comparing 20L over 2.5 vs 6-8 hours. I would point out that my 30L and 40L regimens were conducted over essentially the same time frame which would also suggest that NxStage is underutilizing the dialysate dosage since I had a significant improvement in urea clearance as well as maintaining P04 levels. For a four hour session on 30L, I was able to get a 20% improvement in spKt/V by going to 40L at a higher FF at essentially the same cost in time. The issue of extending the time at 20L is also outside of the envelope of recommended FF that should likewise be explored as you suggest.

As the article mentions, P04 and B2M clearances are much more time dependent than Urea clearances, but even here, I have seen an improvement in my P04 levels as well which further suggests that dialysate dosages may be lower than what the machine could achieve in the same time frame. I believe that is the entire argument of optimal dialysis not only with regards to frequency and duration but likewise efficacy of high flux filters and other technical issues dealing with the how well the machine and it's components filter. Comparing my 30L results to my 40L results over an equivalent time period suggests to me that there is significant room for improvement of dialysate dosages. I am pleased that NKC incorporates this concept into their NxStage prescriptions going beyond the standard NxStage dosages. I am simply questioning what is the maximum benefit we can get in the most timely manner? I have not found that question even explored in the NxStage literature to date and I believe it should be.

Another area that should be answered is the issue of pre-packaged dialysate bags vs the Pureflow. It has been shown that ultra pure dialysate reduces inflammation and B2M levels which are increased by higher levels of bacterial endotoxins in the dialysate. Europe has stricter standards than America for endotoxins. I have searched diligently for specific information on Pureflow and have not been able to find that information in the literature. I am sure that NxStage publishes this data somewhere, but it is not easily accessed.

I greatly appreciate the article on NxStage solute kinetics from an independent investigator. I would truly appreciate seeing many more issues so addressed in the near future by independent researchers since the benefit of having a portable machine to use in the comfort of my own house is a paramount benefit and it is easy to learn and set up as well. But we do need a better base of basic research available for a truly informed consent to make the best individual choice on renal replacement therapies available today.

[somerville]

These results cast a sobering shadow over all the previously wild enthusiasm over home short daily dialysis being 'the answer' to endstage renal disease. Even if some of the shortfall can be made up by increasing the dialysis time, the gains in quality of life by improving the patient's blood values will be discounted by the loss in quality of life from the additional treatment burden.

[Peter Laird, MD]

Dear Somerville, I am not sure that I would interpret my comments in the same light that you have. My days are open to me and my evenings keep me alive. I find that a small burden compared to the benefits. On the other hand, those that may be interested in nocturnal home hemodialysis should consider the NxStage machine at the higher end of the dosage scheme. The convenience of setting up, no reverse osmosis to deal with and no additional plumbing accomodations in addition to having a portable machine still make the NxStage an attractive device. I simply believe it should be taken to a maximum dosage.

On the other hand, daily home dialysis is not for everyone. Fortunately we have many alternative renal replacement therapies to choose from. All have their own risks and associated benefits from which we can choose according to our individual lifestyles. Having to deal with the complex set up and maintenance with a Baby K for instance would be an undue burden in my mind. In addition, having a Baby K and wanting to be able to visit my family would mean that I would have to go back in center for the duration of that visit. Since I have been able to achieve nearly 70% of my in center clearances on this tiny portable machine, I find that more than adequate.

So, the burden of living with renal disease no matter which renal replacement therapy that you choose leaves us all with individual choices to make. For myself, I like very much having the option to take the NxStage to the max. It works well for me. I hope you are able to find your own best option if you are likewise a renal patient as well.

[Miriam]

Somerville,

I agree with you that SDD is not necessarily the "answer" to CKD5, but I don't think there is any perfect answer, only choices that each have pros and cons.

As someone who is not eligible for a transplant, I appreciate the positives of the NxStage system, while accepting its limitations, and have been able to have a quality of life I wouldn't otherwise have in-center. I think Peter's point that there is more research to be done to maximize the dialysis doses that the machine is capable of is valid. That way people who choose it can get treatment that will support a realistic quality of life.

Miriam

[Zach]

How's the old transplant, Stauffenberg/Somerville?

[somerville]

I was offered home hemodialysis, but it seemed to me like being put in the situation of someone not only condemned to death, but also forced to construct my own scaffold and dig my own grave. At least with in-center hemodialysis, someone else had to assemble the supplies, operate the machine, ensure quality control, and house all the equipment, so it was like having a butler to do my household chores rather than having to do them myself, as would be the case with home hemodialysis. Also, the option that my dialysis facility offered required me to appear at the hospital for numerous blood tests per month which I was not allowed to perform at home, and with all the delays and inefficiencies in the way hospital labs are run, I was going to have to spend a large percentage of my time at the hospital even after the 'liberation' from such visits with home hemodialysis. At least with in-center dialysis, my own home was still a refuge from the medicalization of my life and four days of the week were completely free of renal duties.

Fortunately my renal graft keeps on ticking, now five years after the transplant.

[David]

Dr. Laird,
Thank you for writing this article!! I feel vindicated. I used a similar dialysis prescription with my patients. But was told not to continue due to NxStage guidelines. I knew this was good for our patients!!

[Erich Ditschman]

Thank you Dr. Laird. I agree that we have not yet maximized the treatment capabilities of the NxStage.

One of the good things about ESRD is like what was mentioned above, we have many options for treatment. Having two failed kidney transplants due to FSGS, I'm not holding my breath for the third.

As a father of two young children, regardless of how it is administered I see dialysis as a true gift of life. Without it I'm dead and my children are fatherless.

Moving from in-center four years ago to home hemo has been a real blessing. I agree with Dr. Laird that my time dialyzing at night is not wasted, rather it is what helps me to get up in the morning smiling. I never once smiled on my way to a Dialysis Clinic.

Now that I have dialyzed for ten years I have a very different outlook than perhaps anytime during the first five years. For me, my NxStage is just a glorified toilet. Just like I don't think much about flushing the toilet, I don't spend much time thinking about my System One.

Thanks again Dr. Laird and keep up the great work. I hope it inspires others to engage in similar research.

Dialyze for the Prize! Erich

[Peter Laird, MD]

Dear David, I have taken a very hard line on the fact that nephologist's are accountable for America's outcomes. The fact remains that only licensed nephrologists prescribe dialysis, not insurance companies and not dialysis machine makers. I have done this simply to urge nephrologists to reassert control over all dialysis issues and renew the standard of care here in America. Gary at RenalWeb had an interesting article on the need of a paradigm shift in dialysis:

The path to a paradigm shift in hemodialysis

Many old perspectives, which might stand in the way of this sorely needed paradigm shift are also examined. These old perspectives make up a fabric of excuses that has delayed—and, if not discarded, will continue to delay—progress toward a survival and well-being outlook for dialysis patients just as favorable as might be achieved through kidney transplant.

http://www3.interscience.wiley.com/journal/123281656/abstract?CRETRY=1&SRETRY=0

I believe that this paradigm shift is as near as the next prescription of dialysis written here in America. We have the evidence and the paradigm to shift immediately. Nephrologists are accountable and need to take charge of their prescribing power once again from those who have usurped this power. It is time that nephrologists optimize their therapies as we do everywhere else in medical practice. It is interesting to read of new cardiac procedures that reduce the rate of death from myocardial infarctions by one or two percent and these studies make national headlines. What about optimal dialysis that may reduce mortality by 30-60% as noted in many studies? I agree that we need a path to a paradigm shift that begins one dialysis prescription at a time.

[Mel Hodge]

Dr. Laird is exactly right -- the "paradigm shift is as near as the next prescription of dialysis written here in America" (I'm the author of the paper, "The Path to a Paradigm Shift in Hemodialysis" which appears in Hemodialysis International 2010; 14 5-10). Dialysis mode selection is about LIFE -- it's quality and duration, not merely 'lifestyle'. In this paper I've drawn an analogy between five year survival with various dialysis modes and how many bullets you load in the gun before commencing a game of Russian Roulette. Only the nephrologist is in a position to get the patient to understand how important it is to commence the longest, most frequent dialysis that he (or she) is capable of -- considered together with the capability of an available partner, if any. In my view, anyone who is physically, mentally and emotionally capable of learning to safely drive a car is also capable of managing 6x nocturnal hemodialysis at home (my BMW manual is twice as thick as either my 2008K or NxStage manuals). And adding your name to the transplant list is no great solution either -- it's about the same as playing the game with three bullets!

[Peter Laird, MD]

Dear Mel, thank you for the kind comments. Many have estimated that as many as 30% of dialysis patients could complete their treatments at home yet we are only around 1% of the dialysis population at home now on hemodialysis. There are many factors in this poor performance, one of the most import is that of the nephrologist who is in control of all dialysis prescriptions. I am used to the many other disciplines of medicine maxing out the benefits of their treatments. It is time for the mindset of maximum dialysis benefits which is likewise often the least expensive route as well.

[Ken Tipton]

I am a new patient on home dialysis using the NxStage machine. My current prescription is for 15 L with a ff set at 35 and a flow rate of 350. My last ktv was 2.97. When I was on 20 L my ktv was 3.58 but I was told that was excessive. I insisted on a lower flow rate but was told 425 was much better than 350. What do you think?
Ken Tipton

[Ricky Leroy]

I been on nxstage for 2 and half years and i do nocturnal 7 hours with a blood flow rate of 280 dialysis rate of around 4.5 30 liters ff about 28 to 30 and i have more energy then i did when i was in center my phosphorus is being reduced greatly my potassium is being reduced greatly they even want me to eat a bit more if i can safely. all i can say is doing correctly nxstage is better then incenter and its allot gentler on the body then the incenter machines im not as tired off treatment and i never crashed so far from being on nxstage. i do everything myself and i dont have to worry about the techs not paying attention to the sticks i do all that myself over all i am 95 percent in control of my own treatment time and care you just have to understand most men need at least 25 l of dialysis fluid and if your bigger build then maybe 30 for sure.
i recommend this treatment to anyone able to do it the mortality rate in center is 50 percent within 5 years look up the stats its there its not from dialysis its do to heart damage that the big machines cause i hope you find this information useful and remember any dialysis is better then none