Don’t Flog the Fistulas: Slow Hemodialysis Blood Flow!

This blog post was made by Dr. John Agar on March 14th, 2014.
Don’t Flog the Fistulas:  Slow Hemodialysis Blood Flow!

The use of excessively high blood flow rates (read "pump speed") during dialysis—flow rates of upwards of 350 ml/minute—appears to be a US-only phenomenon (read "tragedy"). They are symptomatic of the short-hour dialysis epidemic that is also a US-only phenomenon.

When will US nephrologists learn?

The mean blood flow rate in the US (DOPPS 2011) is ~450 ml/min. The mean blood flow rate in Australia and New Zealand is ~300 ml/min (~36% less). Blood flow rates in Australia and New Zealand are similar to those used throughout Europe, and both are still greater than flow rates used in Japan. Patient session times in the US are also markedly shorter than in any other country. And, patient survival in the US is dramatically less than in any other country—yet patient age, incidence/prevalence of diabetes, and cardiovascular morbidity is no different.

The flawed logic of US dialysis, driven as it is by the twin forces of profit and through-put, is that short, and commonly also infrequent dialysis is somehow "OK." Well, it is not OK. The misguided view that shorter treatment times—only possible if blood flow rates are screwed way up in an attempt to achieve the CMS-approved Kt/V (also a flawed and discredited measure of dialysis) are somehow 'acceptable', is a fallacy that has benighted US dialysis for more than two decades.

Speaker after speaker at the recent Annual Dialysis Conference in Atlanta (February 8th - 11th 2013)—myself included, in all of my four separate addresses to the conference, including the conference-opening Keynote speech—pleaded for longer, more frequent and gentler dialysis regimens.

Speaker after speaker emphasised the benefits of slower blood flow rates and longer dialysis time on patient symptomatology (nausea and vomiting, cramp induction, in-treatment hypotension, post-treatment recovery time), on middle molecular clearance from deep compartmental tissues (Eloot)1, on prevention of myocardial and other organ 'stunning' that accompanies rapid volume contraction (McIntyre), and on quality of life and survival.

Nephrologists who do not understand the simple principles and widely documented advantages of slower volume removal and better solute clearance that accompany longer time on dialysis simply do not understand the first principles of dialysis.

They might do well to read the literature that confirms these unassailable dialysis facts. They might do well to hear the message—a message given and shared by every dialysis expert—that the only...repeat ONLY...determinant of good dialysis, of a well patient, and of a long-surviving patient, is the time spent each week on dialysis: the weekly membrane contact time.2

They are the poorer if they have not read and understood the potent message about 'time and frequency' left to us by Belding Scribner and Dimitri Oreopoulos3 – the two regarded widely as the 'fathers of modern maintenance dialysis' ('Scrib' for HD and Dimitri for PD). This meaasge was contained in their lightning-rod 2002 paper: The Hemodialysis Product (HDP): A Better Index of Dialysis Adequacy than Kt/V.3

They might even do well to attend the next ADC.

It is self-evident and has been long understood that the NCDS study, the study that spawned the iniquitous concept of Kt/V, got it badly (and sadly) wrong. It was not 'K' that mattered...it was 't'. Boosting K, by employing an ever faster and more furious pump speed to allow the contraction of 't', is incorrect. It kills people! Increasing 't' and, in the process, allowing the speed and ferocity of the dialysis process to be dialled back, saves people. It saves well-being as well as lives.

On a different but parallel plane, the December 2013 issue of CJASN featured a special section on fistula flow and flow dynamics. It emphasised the many causes of turbulence that accompany venous limb endothelial damage and in-fistula stenosis. One of these is the interruption and/or disruption of normal vascular laminar flow that occurs when the venous needle return jets into and against the venous endothelium at the site of venous return, creating physical turbulence and biochemical excitation of nitric oxide production...factors intimately associated with up-stream in-vessel stenosis.

At a symptom level, short dialysis treatments are symptom-rich; long treatments are symptom-free. Shorter treatments induce ever more cramp, hypotension, and misery. The shorter the treatment, the more comes the complaint: "I can't take this anymore" ...and the louder the pleas to "take me off".

Just think about it ...

  • The shorter the treatment, the faster the removal of fluid must be to attain "dry weight".
  • The faster the fluid removal, the more there is a risk of hypotension.
  • The greater the risk of hypotension, the more likely is the need for saline resuscitation.
  • The more saline that is given, the greater the counterproductive re-infusion of salt and water—and isn't this exactly what the dialysis process has been intent on removing?
  • The greater the rate of contraction of the circulating blood volume, the greater the dimension of organ "stun"...and this affects more than just the heart!
  • Residual renal function plummets as repeated acute kidney injury results from renal ischaemia.
  • Cerebral function suffers from repeated hypo-perfusive cerebral injury.

The list is endless, yet somehow, the ignorance goes on. Yet, the cure is so simple that is beggars description that it has been so long ignored. Gentleness...respect for our patients and their physiology, and, above all, time.

Speaker after speaker at the ADC said it. Speaker after speaker pleaded.

Slow it down, America.

References:

  1. Eloot S, Vanholder R, Van Biesen W. Dialysis duration: the longer the better, but why? [corrected]. Nephrol Dial Transplant. 2012 Nov;27(11):3975-8
  2. Agar JWM, MacGregor MS, Blagg CR. Chronic Maintenance Hemodialysis: Making sense of hemodialysis terminology. Hemodialysis Int. 11(2): 252-262, April 2007
  3. Scribner BH, Oreopoulos DG, The Hemodialysis Product (HDP): A Better Index of Dialysis Adequacy than Kt/V, Dialysis & Transplantation, 2002 Jan;31(1):13-15

Comments

  • JW

    Dec 5, 11:49 AM

    I'd suggest not just in the USA.

    My pump speed was reduced to 330, after consultation with my renal cardiologist (yep we had one).

    And yet I read of a lot of other UK patients almost 'boasting' of higher pump speeds they can reach.

    I also read a LOT about failed fistulas, wether first surgery isn't as good, or immediate aftercare isn't given. There are too many factors to make a decision there.

    Certainly for home heamo over here nocturnal and short daily are encouraged where possible. (Although I note your not a fan of short daily:))

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    • John Agar

      Dec 5, 10:31 PM

      Yes, you are right ... I DO like slower, lower, longer and more frequent. And I am heartened to hear that home nocturnal is being encouraged in the UK, and yes, I DO prefer it to short daily

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  • jerry howell

    Feb 26, 2:45 AM

    Thank you Dr.Agar, and all that answered. I am back at clinic as I lost my helper. I use a Fresenius 20008T machine there. They were running me at 450 for 4 hours. I have changed it to 350 for 4 and 1/2 hours. The machine runs green the whole time. I tried 300 but will not work at that time length.
    They told me I need to try nocturnal dialysis. However, they do not have it in the area. I would stay on for 5 or 6 hours to attain 300 blood flow rate. I guess I will have to be happy with what I have. I also realize that they have a bottom line to contend with and the machines there at clinic are different than the home units and are designed to operate at high blood flow rates for the bottom line.
    Thank you for all help and suggestions;
    God bless;
    Jerry

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    • chris walton

      Dec 6, 2:02 AM

      I too was running for some years at 450/460 on a Fresenius 5008S with a dialysate flow factor of 1.2 (540/552)
      Now I run pump speed of 350 with diaysate flow factor of 2.0 (700)
      I am hoping some of the associated problems I have will improve with these settings. Always done 4 hours 3 times a week.

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  • jerry howell

    Feb 3, 9:44 PM

    Great site; Just stumbled on to it as I was searching web for answers to my dialysis venture; Have a strong fistula and have been informed that I may have a problem with it. It has a strong thrill and has worked well for me. I self cannulate with sharps as blunts did not go in well. My dialysis machine at clinic just started running yellow for whole treatment. I had it checked and everything was put in correct. I run on profile one. My blood flow rate is set at 450 I had it dropped from 500 and feel better . I think if I stay on longer than 4 hours and drop flow fro 450 to 350 or 400 I may run green again. I do not want to mess with my site as I think it is still good.??What do you think.?? I have done this at home but my wife did not like to help with it as a needle came out and soaked her with blood. Plus machine broke and we couldn't get a part for it right away.I am 75 years of age and will probably not get a transplant as I think younger people should get them first as they are more productive. I have time to set in my chair and read. Thank you for your help and God bless all those that help us and each other;

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    • John Agar

      Feb 4, 7:36 PM

      I have a strong fistula and have been informed that I may have a problem with it. While It has a strong thrill and has worked well for me.

      Response: It is common for many fistulas to eventually run into difficulty – whether with stenosis (narrowings or constrictions in either the feed ‘arterial’ or run-off ‘venous’ vessel), or aneurysmal dilatation (a ballooning of the wall of the vessel from wall weakening – often due to repeated area puncturing for cannulation, or, hopefully now only in the days of yore, from antegrade insertion of the arterial needle). Most fistula problems can be fixed by either radiological angioplasty (stretching-up of the narrowed segment with a balloon – though these commonly are temporary fixes and the stenosis returns), or by a good and careful fistula-friendly vascular surgeon.

      I self cannulate with sharps as blunts did not go in well.

      Response: That’s fine, not all patients can (or should) use Twardowski’s button-hole technique. While it is good for some, either it isn’t appropriate, or it doesn't work well, for others. But avoid area puncture. But, when using the ladder technique, ensure your home team sets a good ladder plan for you so that the needle sites are spread over a good length of vein and are rotated carefully at both the arterial and venous sites – thus maximizing the available insertion area.

      My dialysis machine at clinic just started running yellow for whole treatment. I had it checked and everything was put in correct. I run on profile one.

      Response: We do NOT use the NxStage system and while I understand what you are telling me, I am not skilled in this machine by repetitive use and thus it would be wrong for me to pass comment.

      My blood flow rate is set at 450 I had it dropped from 500 and feel better . I think if I stay on longer than 4 hours and drop flow from 450 to 350 or 400 I may run green again.

      Response: Those are blood flow rates that are – in my view – stratospheric! The blog explains why longer, slower dialysis is better, but doesn't fully explain why I believe that high rates are ‘bad’ for the fistula.
      see … http://homedialysis.org/life-at-home/articles/blood-pump-speed-and-your-dialysis-fistula a
      and … http://forums.homedialysis.org/threads/1668-Blood-Flow-dialysate-flow-amp-fistula-life
      or … http://forums.homedialysis.org/archive/index.php/t-3362.html

      I do not want to mess with my site as I think it is still good? What do you think? I have done this at home but my wife did not like to help with it as a needle came out and soaked her with blood. Plus machine broke and we couldn't get a part for it right away. I am 75 years of age and will probably not get a transplant as I think younger people should get them first as they are more productive. I have time to set in my chair and read.

      Response: You have rather neatly answered your own question with your last sentence! My view? … slow it all down … take a bit (or a lot) longer for your sessions. Clearly, though, this MUST be after due consultation with and with the advice and approval of your team. Never just ‘do it’ because some wraith from the Internet has said you should. That said, you have my views … !

      Thank you for your help and God bless all those that help us, and each other.

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  • Greg francis

    Jan 5, 4:47 PM

    Have been a home dialysis patient for four years. Over that period of time I have always run at a pump speed of 290' why that figure I don't exactly know but that was the speed my unit but me on when I was learning so have keeped at this speed. I use the buttonhole method using 15 g sharps and in the last three years have never had a bleed. Canulationg at exactly the same angles and to the same deeph each time.There have been a number of times I had to go into our unit to have my treatment, wife was in hospital, DRs and nurses said I should not be using this method but did agree that it works for me. I guess everyone is different. My fistula looks fine and causes no pain so will carry on with this method. Greg

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    • John Agar

      Jan 5, 6:25 PM

      Sounds like all is good, Greg. I am interested that you still use sharps yet needle using the buttonhole method - mostly after a track is formed with sharps, a switch to blunts follows, but if it is working for you, that's what counts. You don't give any indication of your hours but I would feel quite comfy with a flow rate of 290. If you are on overnight, long, slow, 8 hour-ish durations, then even slower would be fine, but if you are doing short daily or more conventional duration then 290 sounds fine to me. If it works, don't fiddle.

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  • Jean Lynch

    Jan 5, 12:39 PM

    What is a good amount of time to be on dialysis? I'm on for thre hours and it feels like forever. I do often suffer from low BP and I'm exhausted and cold after every treatment. This is a very interesting article.

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    • Dori

      Jan 5, 5:43 PM

      Jean, Dr. Agar has given you excellent, excellent advice. He is from Australia, where the average HD treatment is about 5 hours. Here in the U.S.--which has the poorest dialysis survival in the civilized world--it is less than 4 hours, which data suggest would be a good minimum. If you are on Facebook, please consider joining our Home Dialysis Central discussion group. (https://www.facebook.com/groups/HomeDialysisCentral/) Folks there will be thrilled to tell you how much better they feel getting more dialysis. I know it seems counterintuitive that you would want MORE of something that makes you feel bad now, but slower, gentler dialysis can give you your life and your energy back. You might also want to read this blog post: http://homedialysis.org/news-and-research/blog/61-my-labs-are-great-but

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    • John Agar

      Jan 5, 5:14 PM

      Dear Jean … while this is in no way meant as a personal criticism of you or of your question as each person who asks this question asks it afresh - for them … I DO feel like a cracked record giving this same answer yet again! To be honest, I have given this same answer, over, and over, and over again - and I still haven't found a way or reason to say it any differently ...

      The gentler, the slower, the longer and the more frequent your dialysis treatment is ... the better you will feel, the less symptomatic will be the treatment itself, the more healthy you will feel, the longer you will live, and the more at peace with your (sadly essential) treatment you will become.

      No-one wants to be on dialysis. No-one would choose it as a career path or job. No-one. But, the sad fact is, that if you are on dialysis, you are there for one single reason - your kidneys no longer work. There are then only three choices: transplantation (the best option), dialysis (the next best), or death.

      Transplantation comes - sooner or later - for some. But ... and this is something the general public and the media often don't get ... transplantation is NOT an option for many dialysis patients where age, co-morbidity (other illnesses or health factors), or immune system issues prevent listing. In Australia, for example, only about 1 in 4 dialysis patients are suitable for consideration for a transplantation. And the same is true, whatever the country of origin. It is a sad fact that more than 75% of dialysis patients are dialysis-bound ... into their future.

      Dialysis can be made to work for you, if you work with it, not against it. Accepting that dialysis IS your lot, is hard ... there is no doubt of that ... but once you do, then understanding dialysis and how to make it work for you becomes the essential next step. And, dialysis is NOT a fast, wham-bam therapy. The slower (and, yes, longer) your treatments, the more gently your biochemistry can be modified and the less symptomatic that recurrent modification becomes. The slower fluid is removed, the less unstable the blood pressure is, and the more stable is the circulation. There is a saying "Rome wasn't built in a day" ... and it applies to dialysis.

      You will find a number of articles at the KidneyViews site, written by myself and by others, that explain WHY slow dialysis is best.

      And ... yes ... I really DO get it that chair-time sucks. That is why I (and others) encourage as many as possible to embrace overnight sleep-time dialysis so that (1) longer time can be easily accessed while at the same time (2) daytime hours are freed up for 'life' and 'living' and at the least, alternate day (or better, alternate night) treatment can be accessed to exclude the dreaded and lethal 'long break'.

      So, to answer your question ... how long? The real answer is, as long as is humanly and logistically possible.

      3 hours? Well, if you were doing that every day (and who would or could) maybe 3 hours might do it. But I suspect your 3 hours isn't daily. I prefer 8 hours x a minimum of alternate night ... or even better ... a 2 nights on, one off regimen.

      I am NOT a fan of short daily dialysis ... and I have written much on this already and can only suggest you access either the old message boards or previous blogs to find out why.

      As for feeling cold … there has been a log discussion about this at the HDC Facebook page just in the last week and Dori asked me to make some comments there regarding dialysate temperature and the sensation of cold. Another unpalatable truth about dialysis is that lower dialysate temperatures are beneficial – even though so-doing increases the sensation of coldness in a small but significant number of patients. An excellent review of this was recently published by Gihad Nesrallah and his Canadian group (AJKD Dec 2015) that confirmed the advantages to both circulatory and blood pressure stability but also noted that feeling ‘cold’ was reported nearly 3 times as often by the low temperature groups. The FaceBook discussion listed a number of user ways to counter this feeling of coldness.

      At the end of the day … while longer treatment lengths and lower dialysate temperature clearly have their ‘negatives’ – undeniably these are (1) chair time and (2) a feeling of coldness or chill – both will also undeniably improve your clinical, health and survival outcomes.

      The ultimate choice remains between you and your team but, I know that if I were to be on dialysis, I would be dialysing for as long as I possibly could and would be wearing a beanie and covering up with a snuggly rug to counter my choice for a lower dialysate temperature.

      I hope you won't mind but I have taken the liberty of sending a copy of your question and this answer to Dori Schatell at HDC. She may wish (or be able) to put you in touch with Henry or some of the other experienced dialysis patients who understand this well and have a wealth of self-experience. It might be useful for you to have access to their views and thoughts, as these may be helpful in aiding your appreciation of this one single and over-riding principle of dialysis ... the longer, the slower, the more frequent and the more gentle your dialysis treatment, the better.

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  • Zoi

    Dec 18, 10:22 PM

    My husband has been on dialysis since he was 19. He's 36 right now. In May of this year, he started home hemo and now runs 6-8 hour treatments instead of the 4 hours that he got in centre and he looks and feels like a new person. We're 8 months into this new program and his labs look great. His skin and hair even look different. Longer hours and slower rates have improved his overall health and quality of health. It's really amazing.

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  • liz

    Feb 10, 10:06 PM

    Can high bfr cause chronic coughing?
    A patient continuously coughs during tx..rn thinks its do to high bfr ...

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    • John Agar

      Feb 11, 11:32 PM

      That is an interesting question.

      There are a number of reasons why hemodialysis patients might cough, but I am really struggling to come up with a cogent reason why your husband might cough just during dialysis.

      Thinking about cough and hemodialysis (NB: PD and cough have been linked), first and foremost, cough may be a feature of chronic fluid (volume) overload. However, in the situation you describe, if the cough is fluid-related I would have expected the cough to improve as fluid is removed and dialysis progresses. So, that seems at odds with your husband’s situation where the cough is seems to be promoted by dialysis.

      Many dialysis patients are on ACE inhibitors (medications ending in ‘pril’). These agents quite commonly cause cough. However, I would not have thought that a ‘pril’-related cough would occur only during dialysis … but, if he is on a ‘pril’ it might be worth discussing with your dialysis team whether this medication could be discontinued for a week or so, just on the off-chance it might help. That said, I have some difficulty matching a mechanism to the suggestion I have just made!

      Neither of these would seem to be in any way directly or indirectly related to access flow.

      Cough, is a potential symptom of pulmonary hypertension (PHT), and PHT is a common problem in hemodialysis patients – especially where chronic fluid overload contributes to congestive cardiac failure. But, in this circumstance, it might be expected to improve with fluid reduction. However, high flow AVF’s have also been shown to promote or contribute to a high output left ventricular failure state by acting as a circulatory-based left to right short-circuiting shunt. In this case, one could potentially visualize an AVF playing a role … but it is, at best, a tenuous argument. Indeed, I am struggling to come up with a cogent mechanism.

      Many, many years ago, in the old days of bio-incompatible cuprophane membranes, complement activation and the subsequent sequestration (accumulation) of macrophages (white blood cells) in the pulmonary circulation often led to acute shortness of breath and cough about 10 minutes into the dialysis treatment, but since we now use bio-compatible membranes, this early-days complication of dialysis has, to my knowledge, not been reported for decades.

      Though a high return flow through an AVF might (even will) create local turbulence and be a contributing factor to local vein damage upstream from the venous return needle, I would not expect this to affect pulmonary flow and/or promote symptomatic cough.

      Chronic pulmonary disease may also, clearly, cause cough, but not specifically promoted by dialysis, unless the removal of fluid leads to alveolar re-expansion and, secondarily, an irritant cough.

      So … I am sorry, but I don’t think I have been much help.

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  • Barbara Claussen

    Apr 22, 12:06 PM

    Thank you, Dr. Agar for your response. I will pass on this information to my dialysis people. I deal with very low bp....both on TX and off....have finally gotten them to extend my TX time to 4 and 1/2 hrs....and that has helped.

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  • John Agar

    Apr 21, 8:42 AM

    In the blog (above) I describe that .... "turbulence ... interrupts and/or disrupts the normal vascular laminar flow in the fistula as the venous needle return jets into and against the venous endothelium at the site of venous return This creates physical turbulence and biochemical excitation of nitric oxide production...factors intimately associated with up-stream in-vessel stenosis. The greater the rate of venous return, the greater the disruption of flow and distortion of the upstream vessel".

    While it is a simple matter of mechanics, the distortion and vibration set up by the return flow from the venous needle - and the greater the flow rate, the greater the effect - also cause the formation and release of chemicals that induce oxidative stress and tissue injury. However, this is best explained and determined by your physician as not all stenosis are related to these mechanisms. However, high venous flows are well described to contribute to many upstream issues in AVF.

    Slowing the flow rate simply lessens the contribution of flow rate to fistula failure.

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  • Barbara Claussen

    Apr 20, 7:09 PM

    How would lower flow rates play in the part of less stenouses developing? This has been an ongoing challenge for me......so if slowing the rate would lessen the incidence of stenous....I need to know.......thanks.

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  • Dr. O .

    Mar 15, 9:01 AM

    Great post Dr. Agar. Right on target. Blood flow speeds in the US are ridiculously fast.

    I hope every home dialyzer will slow down their blood speed. We have slowed ours down to 340 .

    Our KT/V (which of course is flawed) still runs 3.24 so slowing down from 400 did not compromise dialysis for us on NxStage.

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  • Lance Holt

    Mar 14, 5:30 PM

    Good on ya John. If you were a rock star, I'd be one of your groupies (and I'm not even that sort of a fella). I am however, a disciple and beneficiary of your hot-gospelling dialysis advocacy and methodology.

    "You can hear the truth, but you've gotta choose it!"
    Dylan

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