Henning’s Corner of the World: Shotgun Dialysis vs. Healthy Dialysis

Here in Denmark where I live (most of the time and officially) many, if not all, doctors dealing with dialysis say that the NxStage machine doesn’t ‘clean as well’ as other machines on the market. That is a truth with modification, to say the least. I am convinced that this statement is something that was created by and continues to be perpetuated by representatives from other companies, like Fresenius and Baxter. However, I also think there is something to it if one views it in a certain light.

In the US there is an entirely different problem that I want to address. I read about many patients who are running at what I would term ridiculous blood flow rates. A rate of 400-500 is not uncommon. To me, those sorts of speeds are rife with problems. No wonder problems like stenosis and thrombosis seem so much more prevalent here than in other parts of the World.

You might ask what these two things have in common. On the surface apparently nothing. But in reality they are signs of an insidious underlying problem. Then again it’s not really a problem as such. It’s a matter of understanding and acknowledging the simple truth that dialysis takes time.

This basic fact is something that all doctors know and willingly talk about when asked. Articles abound in the field about time needed for effective dialysis. Nephrologists write in their blogs about patients needing more time. But in a completely misguided sort of ‘care’ for their patients they are often not willing to acknowledge this fact, nor do they teach it to the very patients that need this information the most.

The excuses are manifold, but most typically doctors will claim that the patients don’t want to dialyze for the time that is necessary – and of course they don’t. Who wants to do more treatment than what their doctors tell them is necessary? Not me, that’s for sure. But I will spend the extra time when I am told the truth. The truth is that I will feel better, I will be in much better health and I will live far longer when I engage in proper dialysis.

What most people are taught is shotgun dialysis. It doesn’t matter if it’s in-center or at home (at least here in Denmark, where the home hemo standard is about 3 hours 3-4 times a week – far from enough to live a healthy life). They are told that it is ‘adequate’ and in many cases it is adequate – for survival and for short term health. But it is NOT adequate to live a somewhat decent life. Shotgun dialysis is only barely enough to not end up in the hospital time and again.

It is quite logical that we as patients don’t want to spend a minute extra on the machine. But the logic breaks down when it turns out that by spending that little extra time in treatment, we get way more time at the other end. Time where we feel good and we are able to do the things we really want to do.

Unfortunately,  there is but one simple fact that determines good dialysis and therefore also determines our longevity. It is the amount of hours spent every week cleaning our blood – and don’t buy into the idea that high blood flow can decrease that time (I will get to why in a moment).

The post-treatment recovery time is just one (some might even claim, minor) problem associated with shotgun dialysis. The body can’t really get rid of its extra fluid in such a short period of time. The fluid that is removed is what is in the bloodstream but we also have a build-up of fluids inside the cells and between the cells and that fluid does not have time to enter the bloodstream during short infrequent sessions. That means the body suddenly feels dehydrated because the fluid from the bloodstream is drained. BP drops and people cramp. This feeling is a major reason people hate dialysis. However, in reality, they are not dehydrated, yet they get a saline bolus and end up over-hydrated at the end of treatment. This is VERY hard on the heart, as it has a rough time trying to keep up with high blood pressure as a result.  This is referred to as cardiac stunning.

Also, tons of toxic agents (the so-called middle molecules, amongst them phosphate, are not removed adequately by shotgun dialysis. They will slowly build up and mess with our system so we feel terrible from having these toxins in our bodies.

Back in 2002,  Belding Scribner, the ‘father’ of home hemodialysis, wrote an article along with Dimitrios Oreopoulos, the ‘father’ of peritoneal dialysis about why long gentle dialysis is better for us all[1]. In that article they do away with the idea of Kt/V. They say forget about the K (urea clearance) and focus on the t (dialysis time). The simple reason for this is that urea clearance is a really, really bad measure of adequate dialysis since urea is easily removed,  as opposed to the aforementioned middle molecules that take longer to remove. Therefore, time is of the essence here, folks!

Why is it that we are withheld such a basic truth? The two grand old men of dialysis say it very clearly in the article: “Short hemodialysis sessions have great appeal only to the uninformed dialysis patient and to for-profit dialysis centers.” And that is why there is no way in hell we can compensate for longer sessions with those ridiculous blood flow rates I keep hearing about.

That is also why my NxStage machine is equally good for treatment as any Fresenius machine. I will give them that NxStage probably does shotgun dialysis poorly and that is why is has gotten such a bad rap in my country. But it was never made for shotgun dialysis – so there.

In my opinion the 3-page article by Scribner and Oreopoulos ought to be required reading for all doctors before they are ever introduced to their first dialysis patient. Not only does the article do away with the antiquated and flawed idea of Kt/V, it replaces it with one that is much easier to work with. So easy to work with, in fact, that we patients can do it ourselves. So bear with me as I try to explain it (if I do my job properly you can even use it yourself).

They call their measure Home Dialysis Product (HDP). It is calculated thus: (hours/dialysis session) x (dialysis sessions/week)2

So let’s say I do 3 hours 6 times a week, I get 3*62 = 108

The article does not give a solid answer as to how much is enough. It talks about a critical range below 60 and with my actual schedule I end up with a number of 72 – at which I feel great. The regular in-center regime of 3-4 hrs 3 times a week gives a range of 27-36 on this scale, which obviously is far from adequate.

Like my wife wisely says: more time on the machine gives you more time in your life. You get more hours in a day because you have more energy and shorter recovery time. You get more days in a month because you will spend less time being sick and/or hospitalized. Most of all, more time on the machine adds more years to your life because your overall health will be improved. The strain on your heart and the rest of your system is significantly lessened.

This time to live is what we gain by giving up shotgun dialysis. Do you think it’s worth it?

 

3 thoughts on “Henning’s Corner of the World: Shotgun Dialysis vs. Healthy Dialysis

  1. Wonderfully put. Those who have not seen the effects of really “adequate” dialysis rather than just KT/V do not know what most US patients are missing.

  2. Henning, you are so right. If only all the patientswere told of the complete benefits and given a choice they would have better dialysis and be in control of their own life.

  3. Good job Henning!

    Please note that HDP (hemodilaysis product HDP = t * f^2) as described by Scribner does not account for patient weight. Therefore a HDP of 108 may be adequate for someone 70 kg, but not adequate for someone 120 kg.

    You could probably write a new formula for NHDP (normalized hemodialysis product) by using the formula:

    NHDP = t * f^2 * (70 / w)^2

    Where:

    NHDP – normalized hemodialysis product
    t – dialysis time (hours/dialysis session)
    f – dialysis frequency (dialysis sessions/week)
    w – patient weight in kg

    kt/V calculation does take patient weight into account, but why doesn’t it work better? There are at least two factors. One, kt/V monitors only one solute and that is urea, which dialyzes more readily than other molecules and is less predictive of patient outcome. Two, solute rebound occurs frequently after dialysis. Most methods of urea sampling occurs right at the end of dialysis, but in fact urea rebounds within one or two hours after dialysis. Therefore kt/V is often overestimated – you think you may be getting great clearance when in fact the treatment is more moderate.

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