Is 2.5 hrs 3 x week enough?

To all at Home Dialysis Central …

The following demonstrates what I believe you must all work to change … each of you who already have access to better dialysis …

[B][I]I received two emails at my website that made me sad … and mad … both together. I have combined them into a single question. I thought it worth sharing with you.

They come from a US lady who was wondering if there might be better dialysis available for her somewhere nearby her home. While her name is clearly protected, she said the following …

I am on dialysis 2 1/2 hours, 3 x week.
I crash without getting all the fluid off every time.
I am a small person and I am told by my labs that (my dialysis) is giving me good clearance levels.
I have been on and off dialysis for 35 years and have had two transplants during this time.[/I][/B]

I felt that her plight was real and I therefore responded as follows …

Dear …

I need to be careful that I don’t tread on too many toes with this response … it can be a difficult thing to answer critically - but correctly too.

You stated that … “I am told by my labs that it is giving me good clearance levels”

Well … even if a ‘good clearance’ was all there was to decent dialysis, I’d still be gob-smacked by your plight.

Sadly, and this seems especially true of some US dialysis, the word ‘adequate’ has been attached, somewhere along the way, to the process we know of as dialysis.

‘Adequate dialysis’ soon morphs into ‘dialysis adequacy’…. and in the next breath, dialysis adequacy has been equated to ‘urea clearance … and in the next, Kt/V … and the next, the worst cut of all … clear urea to a minimum Kt/V of 1.2 to 1.3 [or a URR of >0.65 (= a PRU of >65%)] and, then, ‘down tools’, ‘turn off the machine’, ‘go home happy’ … thinking … ‘good job, well done’!

Sorry … but that’s just not true!

That kind of thinking – and it is so prevalent too – is just plain, horrible, cruel and unmitigated rubbish!

One of the fallacies … no, one of the 2 key fallacies - and I will come to the 2nd fallacy (= fluid) a little later on … of so-called ‘adequate’ dialysis is this ‘beast’ we have called Kt/V.

[I][INDENT]Kt/V underpins the fatally flawed notion that, somehow …

(1) by demonstrating from a laboratory measurement of a highly un-representative small solute called urea

and …

(2) by using this urea measurement to derive an equally flawed mathematical equation – an equation based in error and derived from an old, old study of 165 non-diabetic, <60 yr old, 1970s dialysis patients studied, in total, for less than a year

that …

(3) the simple ‘clearance’ of urea by dialysis is ‘enough’ to quantify and substantiate ‘good dialysis’

… is just wrong!

Kt/V doesn’t mark good dialysis. It never did. Never will. It is a false measure.[/INDENT][/I]

Good dialysis is far, far more.

You say are a small lady. I know not ‘how small’ you are … indeed I don’t know anything about you except that you did say that you had been ‘on and off dialysis for 35 years’. That says one important thing to me about you … you will have no residual renal function … none. You are likely relying completely, only, and totally on your dialysis for the removal of a slew of metabolic wastes and a whole lot of fluid (see later).

Being small, you (likely) will have a small muscle mass and, as a result, a small creatinine and urea pool. You will have small(er) ‘numbers’ … your ‘labs’ as you call them … with a (likely) relatively low urea and low creatinine, pre-dialysis.

Being small, part of that ‘smallness’ may also be that you are poorly nourished (though I clearly don’t know if this truly applies to you).

Many poorly nourished dialysis patients … and this likely applies to the majority and not just to a minority … have a low PCR (protein catabolic rate) which, in turn, contributes to a (spuriously) low urea … and I wonder if, just maybe, this is contributing to your low ‘numbers’.

Long ago, small numbers were, in general, shown to be bad! A low urea (all too often) represents poor nutrition – not good dialysis – and poor nutrition leads to a poor appetite which, in turn leads to a poor (low) protein catabolic rate = a lower than ideal urea generation capacity. Its a vicious circle, all emanating from poor (or under)dialysis. Most importantly of all, a poor PCR has long been shown and known to be directly causal of a poor dialysis survival outcome.

It is much to your credit that you are still in there ‘batting’ after 35 yrs of CKD. I suspect much of that credit is to
(1) your courage and fight
(2) to some years of good function (guesswork) from your transplant(s).

Good dialysis is far, far more than just Kt/V. Many dialysis specialists in your country - your dialysis thought leaders and dialysis experts (Blagg, Moran, Kjellstrand, Lockridge, Gura, Ing, Twardowski, Port and so many others) - know this only too well. They would be sad, along with me, to hear your question … and I believe that they would agree with my answer.

It is not just a matter of offering dialysis to a ‘given’ Kt/V then … Oh, OK, it’s time to go home … it’s time to turn off the machine and set up for the next patient.

No, a thousand times no!

Good dialysis is far, far more than just clearing (removing) urea … and I suspect that that is exactly what has been meant when you were told that you had ‘good labs’. If so, then I beg to differ. I’ll bet your ‘labs’ aren’t as good as you think! Please take the time to read through the section on ‘Good Dialysis’ at the start of my website @

Do you pass muster?

[I]Though I don’t know you, my guess is that you won’t score too well.

Are you on phosphate binders? … Yes? … then your labs aren’t good!

Are you on any BP pills? … Yes? … then your volume isn’t right

Are you getting dialysis-related symptoms? … Well, I know you are! … you must be – you have stated that 'they can’t get the fluid off’ !

Are you calcium, your phosphate, your PTH levels within an ideal range … my bet is that they will not be … or if they are, at what medication cost … are you taking binders, hefty doses of sevelamer or other medication, or have you had to have a past parathyroidectomy? … all, and more, are features that would tell me that the ‘adequacy’ of your dialysis isn’t all its cracked up to be !

And … there’s more![/I]

Your main complaint in your email to me was that 'they can’t get the fluid off’.

In just 2.5 hrs x 3 sessions per week? … Oh my … it’s no wonder!

With no residual function (my educated guess) and with a measly 7.5 hrs dialysis a week … you must be trying to drink only by the thimble-full. To ask such draconian fluid restriction of any patient is, to me, cruel … even anti-human.

OK … let me show you want I mean … let’s do some simple mathematics!

Let us just say … and I am guessing … that you drink only one litre per day … and, if so, that is draconian fluid restriction! So, for a week, you thus drink +/-7 litres.

I have to say at this point that few humans on this planet can easily sustain a 1L per day total fluid intake, day in, day out, for years. So … my guess is that my estimate of a 7L intake per full week is therefore (likely) ‘conservative’.

You are, by your admission, small. That suggests a small skin surface area. A small surface area will, of itself, diminish your expected losses of fluid from your skin, lungs and bowel … normally +/- 500 ml in a 70 kg person at normal ambient temperatures and a normal core temperature. So, let’s say the unmeasured (called insensible) losses from your body are more like 350-400 ml/day than 500 ml given your smaller surface area (again that is my guesswork, but it’s educated guesswork).

That means that your non-dialysis insensible losses are 400 ml x 7 days = 2800 ml/week … let’s say a rounded-out 3 litres per week.

That means even with draconian fluid restrictions, your intake is 7L per week and with normal insensible losses, you lose unmeasured fluid at 3L per week.

You are (already) in a positive balance of 4L.

But … many forget that there is fluid in food, too. For example, a 250 gm slice of watermelon (96-97% water) = nearly 250 ml of water in! Lettuce? … it’s much the same. Many ‘foods’ are, in effect, fluid.

In addition, most patients forget to count as part of their ‘intake’ the water they use to swallow pills.

Even if you are adding all these sneaky fluid sources to your overall intake, the water you take in when brushing your teeth, swallowing your pills, or which forms part of your food, all adds to your fluid intake. For most of us, this ‘added’ but often ignored ‘extra’ fluid amounts to another 300-500 ml/day.

This is no longer ‘insensible loss’ but ‘insensible gain’.

You can add another 2L plus a week wrapped up in that sneaky fluid you didn’t count!

So, now you have a weekly intake of 7L (your measured intake + 2 L (minimum) of unmeasured intake = 9L per week. After allowing for insensible losses of 3L, you still have a minimum of 6L to get rid of during dialysis.

I’d like to say that it is more. It probably is! Add all your weekly weight gains together and see … Oh … and don’t forget the wash-back fluid at the end of dialysis!

So … back to you. You are being given 7.5 hrs dialysis/week. You have a minimum of 6 litres to remove. That’s about 800 ml per hour, for every hour of dialysis.

Even for a normal sized patient, that’s bad enough … and this bit gets difficult … so, you may need to re-read a few times to ‘get’ it …

Dialysis only accesses and removes ‘stuff’ (wastes and fluid) from the blood stream. When we remove fluid from the blood steam, replacement fluid then kind-of ‘waterfalls’ back into the blood from the fluid that is contained in the tissues of the body (but outside the blood volume). This fluid replaces and balance out with the blood volume. As water moves out of the tissues, the fluid contained within the cells of the body then waterfalls to restore tissue fluid.

So … over time, removing fluid from the blood … removes fluid from the tissues … removes fluid from the cells … a 3-tiered waterfall process.

But …

A normal-sized person (a 70kg human) can only ‘refill’ their blood volume from tissue fluid at about 400 ml/hour. As dialysis only removes fluid from the blood volume and as the maximum rate that fluid can ‘waterfall’ from tissue fluid to ‘refill’ the blood volume is about 400 ml/hour, removing 800 ml/hr from the blood volume exceeds this ‘refill rate’ x 400+ mls/hour, each hour of dialysis.

That means dropping the blood volume by 400 x 4 (if a 4 hr dialysis) = 1600ml in a dialysis session.

But … back to you … you only dialyse for 2.5 hours.

Ok … you are smaller, but, so is your circulating blood volume! Your blood volume pool will be relative to your size and weight! So you have 6L (we established that earlier) to remove from a smaller blood volume within a very short and infrequent dialysis program.

It’s a case of ‘no-can-do!

As we remove fluid, during dialysis, mainly from the blood volume … and you are a little lady … with a small blood volume … removing 800 ml/hour out of you each hour of dialysis is akin to wringing you out like the washing …

No wonder your blood pressure falls, you have ‘flats’, you cramp, you feel dreadful after dialysis and have only just recovered in time for the next onslaught! … and who wouldn’t?

So … you ‘crash’ … go ‘flat’ … cramp …

What does your facility team do? … easy peasy … they run in a slug of saline to restore your conscious state, to bring up your crashed blood pressure, to revive you! …

Well! … that’s smart, eh? … and I thought the whole idea was to remove fluid! … Silly me!

Think about it … there they are, giving back what they have been trying to take off … excess salt and water … and you haven’t even gotten off dialysis yet.

Time … time … time … that’s what fluid removal is all about.

It shouldn’t be a matter of limiting what you comfortably want to drink but of taking plenty of time to remove fluid slowly … gently … without rush … within the ability of your tissue fluid to replenish your blood volume as your dialysis proceeds … within that plasma refill rate of 400 ml/hour (or as close to it as possible). That means longer, slower, gentler dialysis. It means not rushing but extending the dialysis session hours. It means ‘oozing’ off the fluid, not ripping it out of you in a frantic, destabilizing hurry.

Good dialysis should be subliminal and I am afraid that yours isn’t.

So … no … 2.5 hours 3 x week just isn’t enough, not by half.

It is not enough for good solute removal.

It is not enough for fluid management.

Though I know that what is ‘being done to you’ is also ’being done to others’, right across that wide country of yours, that doesn’t make it right.

At the end of the day … and I know I have sounded somewhat incredulous and preachy at what I would not regard as good dialysis and, if the latter, I am sorry, but I am passionate about this … maybe, for some reason that I am quite unaware of, 2.5 hrs x 3/week is all the dialysis that your facility is able to offer.

But, if that is so, then I would be trying to find another facility.

I hope that was helpful to you

John Agar

Here are a couple of references (1) from Dori Schatell and (2) from me that you may wish to show to your home team and that they may like to read:-

1. Saran R, Bragg-Gresham JL, Levin NW, Twardowski ZJ, Wizemann V, Saito A, Kimata N, Gillespie BW, Combe C, Bommer J, Akiba T, Mapes DL, Young EW, Port FK. Longer treatment time and slower ultrafiltration in hemodialysis: associations with reduced mortality in the DOPPS. Kidney Int. 2006 Apr; 69(7): 1222-8.

Longer treatment time (TT) and slower ultrafiltration rate (UFR) are considered advantageous for hemodialysis (HD) patients. The study included 22,000 HD patients from seven countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS). Logistic regression was used to study predictors of TT > 240 min and UFR > 10 ml/h/kg bodyweight. Cox regression was used for survival analyses. Statistical adjustments were made for patient demographics, comorbidities, dose of dialysis (Kt/V), and body size. Europe and Japan had significantly longer (P < 0.0001) average TT than the US (232 and 244 min vs 211 in DOPPS I; 235 and 240 min vs 221 in DOPPS II). Kt/V increased concomitantly with TT in all three regions with the largest absolute difference observed in Japan. TT > 240 min was independently associated with significantly lower relative risk (RR) of mortality (RR = 0.81; P = 0.0005). Every 30 min longer on HD was associated with a 7% lower RR of mortality (RR = 0.93; P < 0.0001). The RR reduction with longer TT was greatest in Japan. A synergistic interaction occurred between Kt/V and TT (P = 0.007) toward mortality reduction. UFR > 10 ml/h/kg was associated with higher odds of intradialytic hypotension (odds ratio = 1.30; P = 0.045) and a higher risk of mortality (RR = 1.09; P = 0.02). Longer TT and higher Kt/V were independently as well as synergistically associated with lower mortality. Rapid UFR during HD was also associated with higher mortality risk. These results warrant a randomized clinical trial of longer dialysis sessions in thrice-weekly HD.

2. Eloot S, Van Biesen W, Dhondt A, Van de Wynkele H, Glorieux G, Verdonck P, Vanholder R. Impact of hemodialysis duration on the removal of uremic retention solutes. Kidney Int. 2008 Mar;73(6):765-70. Epub 2007 Dec 26.

Several studies have stressed the importance of dialysis time in the removal of uremic retention solutes. To further investigate this, nine stable chronic hemodialysis patients were dialyzed for 4, 6, or 8 h processing the same total blood and dialysate volume by the Genius system and high-flux FX80 dialyzers. Inlet blood and outlet dialysate were analyzed for urea, creatinine, phosphorus, and beta2-microglobulin at various times. Total solute removal, dialyzer extraction ratios, and total cleared volumes were significantly larger during prolonged dialysis for urea, creatinine, phosphorus, and beta2-microglobulin. Reduction ratios increased progressively, except for phosphate and beta2-microglobulin, where the ratios remained constant after 2 h. In contrast, no significant difference was found for the reduction ratios of all solutes and Kt/V(urea) between the three different sessions. With longer dialyses, solutes are efficiently removed from the deeper compartments of the patient’s body. Our study shows that care must be taken when using Kt/Vurea or reduction ratios as the only parameters to quantify dialysis adequacy

Cross posted from DSEN

No. Two and half hours of dialysis three times a week is not enough.

By Bill Peckham

Dr. John Agar (friend of DSEN) has a blog like post up on his Home Dialysis Central forum. If Agar’s incoming email is anything like mine he must get a wide variety of correspondence due to his online participation. Emails from people, or the loved ones of people, who are having trouble treating their CKD with dialysis are all too common. I know it can be frustrating to hear the range of care being provided in the US, so I appreciate Agar’s willingness to make himself available.

The question Agar answers comes from someone reporting that they dialyze incenter three times a week for just 150 minutes. Granted, it is an anonymous email that does not provide many details but I see no reason to doubt her situation. I’ve visited units where the average run length is 180 minutes, with many people dialyzing less. Reading CKD discussion boards and listservs it is clear that there are many people in the US who could have written the email Agar answers.

Anyone wondering if 3 hours (or two and a half hours!) of dialysis three times a week is enough dialysis should carefully read Agar’s complete answer. But no, it isn’t enough dialysis.