Treatment Options for Intradialytic Hypotension: Part II

By Peter Laird, MD

Dr. Prince and I seem to be talking past each other with our comments when in many ways we do not actually disagree. I placed dietary salt compliance as the number one issue with intradialytic hypotension in my post as an area that the RFN post did not address but should have. Dietary noncompliance is a difficult issue to deal with of which I do not in the least disagree with Dr. Prince's comments that they are a contributing factor to this problem. Likewise, salt and fluid control by the patient was one of Dr. Scribner's highest ranking issues which Bill can personally attest; Anna added a post on salt restriction today to DSEN.

However, quotidian dialysis regimens, especially daily nocturnal, has shown that dietary restrictions can be nearly completely eliminated including relaxing the sodium limits. High dose dialysis allows lower UFRs due to longer runs and/or more frequent runs and less time between treatments. To the initial point I believe it is these high ultrafiltration rates that are the most important factor causing intradialytic hypotension. 

Granted, some patients simple will not adhere to dietary sodium and fluid restrictions. And these may also be those patients that do not want to dialyze another moment. Nevertheless, even these patients (or especially these patients) could benefit from adding two dialysis treatments a month and those treatments should be offered. The implementation of an every other day dialysis schedule would eliminate the worst day of the conventional dialysis schedule, the day after the dialysis weekend when we see the highest level of fluid overload and we have our highest rate of cardiac deaths. (here and here)

So, while I agree that salt control is part of the solution, I would hope, actually plead, that we all take a look at the conventional American dialysis protocols. These protocols are perhaps an even larger part of the problem than patients that won't comply with salt restriction and fluid requirements.  Simply put, short dialysis sessions which cause the sudden, violent depletion of the vascular compartment are the primary causation of intradialytic hypotension. We all should keep in mind and review Dr. John Agar's information on fluid diffusion rates (pdf link) to understand that the ultrafiltration rates American dialysis centers routinely subject patients to are higher than the physiologic fluid compartment diffusion rate can accommodate. From Agar:

This “waterfall,” of fluid moving from one compartment to another, is rate-limited to a maximum of 350 to 400ml/hr. It takes time for fluid to shift in your body so all is in balance. If fluid is pulled out of the blood too quickly during a standard in-center dialysis treatment, the rest of the chain reaction just can’t keep up. 

Yes, if some one eats at McDonalds all week, all of that salt and extra fluid is going to be sitting in the interstitial spaces throughout their body.  Any dialysis regimen that exceeds the basic diffusion rates of interstitial fluid back into the vascular compartment will cause intradialytic hypotension which must be considered even and perhaps most especially with noncompliant patients.

It is time, it is more than time, to come back to the basics of human physiology and recognize that short, rapid fluid removal is dangerous for anyone even if they are not adhering to good advice on salt restriction. It is time to recognize that there is a rate limiting diffusion process involved in ultrafiltration of fluid overloaded patients that should never be exceeded during fluid removal in usual chronic hemodialysis care.  It is my opinion that it is not only harmful to continue this practice but also cruel to continually subject patients to violent fluid removal leading to the "usual" post dialysis symptoms when they can be avoided by simply acknowledging the basic interstitial to intravascular diffusion rates and then incorporate this into dialysis practice. 

Comments

[Simon Prince]

Dr Laird- well said.

I share your enthusiasm and completely agree in principle. The only issue I have, is that it is just not an appropriate or feasible option for many dialysis patients I care for... They are disabled, may have dementia, or a poor home environment with little to no support. In these cases the home hemo option is dangerous and prohibitive. In-center daily nocturnal would be very costly as you know.. aside from the economic downside, I am all for it... BUT.. this brings me to another point.. If we as a society can stop dialyzing patients that are well into their 80-90s, with endstage co-morbidities, this may free up some of the resources to embark upon such a program as you highlight. Unfortunately, as you know it is not that easy...especially in this economic environment. We are unwilling/ unable to make the tough choices other countries have to limit dialysis to those with even the poorest outlooks.

[Peter Laird, MD]

Dr. Prince, thank you for your engaging and insightful comments. Much of the focus at DSEN has been on the pursuit of optimal dialysis and castigating usual dialysis therapy based mainly on the inadequate dosage of the intervention. As you have stated, it would be your own preference to go on home hemo if dialysis was in your future, which I pray it never is. However, with only 1% of American patients having the availability of this resource, it is a very underutilized modality. We here at DSEN enthusiastically and perhaps even aggressively advocate that it should be made more widely available which gets into CMS and the payment for this modality. We have a long way to go.

Part of the problem that we have encountered is America's love affair with renal transplantation to the exclusion of considering the long term beneficial statistics of quotidian dialysis regimens which have been shown to rival renal transplant survival data. In fact, Australia and New Zealand have achieved 2% mortality for patients dialyzing over 20 hours/week. For patients such as Bill and I with absolute and relative contraindications to transplant, it has been an uphill battle to at times educate our own nephrologists on the home dialysis and quotidian dialysis issues.

I would have to state that Bill has had a much easier time at it since he is part of the NorthWest Kidney Centers where Dr. Belding's influence still runs deep with people such as Dr. Blagg for instance. There are strong arguments for considering home dialysis over even the transplant option in selected patients.

DSEN believes it is time to recognize and embrace the other gift of life in kidney disease which is optimal hemodialysis. Yet, we come up against an entrenched bias against it which is unique to American nephrology that is not found in Japan, Europe and down under. I don't believe it is a sweeping generalization to critique what factors contribute to our last place finish in international dialysis statistics. Most American kidney professionals attribute this to an extended age of our dialysis population with multiple comorbidities and do not address the reality of our failed American dialysis strategy of short, violent dialysis sessions.

Keeping to the issue of intradialytic hypotension, the entire point of my post was to draw attention to the American approach of treating complications that could be avoided if we reevaluated our dialysis protocols and recognized that we are causing many of these symptoms by virtue of the manner in which we dialyze. In other words, the common dialysis symptomotology we see with many of our patients is actually iatrogenic in nature and Europe, Japan and Australia avoid it more often in their patients because that they have rejected short, violent dialysis protocols.

Short, fast and infrequent is the problem with long, slow and frequent the answer. It is a paradigm shift that is based on physiology and outcomes, not economics that gave us short, fast and infrequent in the first place. It is evidence based, not economic based. That in a nut shell is the failure of the American dialysis protocol.

It is time to return to the evidence as American medicine so boldly preaches, but in the case of dialysis patients so totally fails to practice. This may appear as a sweeping generalization on the outset, but at its core is the essential reason why America has a 2.5 times higher mortality rate than Japan. I urge all American nephrologists to consider the evidence compiled by your international colleagues and stop this dance with death that is unique in many ways to America alone.

[Simon Prince]

Your points are very well taken and the dialogue is enjoyable. I have read the studies and agree with your position. I.. like most American Nephrologists I believe would prefer quotidian dialysis. It isn't that we are against it, unaware of it, or think it is deleterious. It is more the feeling of constraint by the American health system that does not allow quotidian dialysis to be a viable option for our patients. I would clearly prefer it to 3.5-4 hr TIW HD for my patients if it was available.

[Peter Laird, MD]

I agree, thank you Dr. Prince for your sincere comments.

[Dori]

Dr. Prince, it is crucial not to look at the poor outcomes of in-center dialysis ("they are disabled, may have dementia...") and use them as reasons to deny people better treatment. Much of the disability seen in in-center dialysis is BECAUSE of in-center dialysis (see: Kutner N., et al, http://www.ncbi.nlm.nih.gov/pubmed/18178781?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum). If more people received better (read: longer and/or more frequent) treatments, many wouldn't be disabled--and some might not have dementia, either. I question how much home support is required, as folks like Bill P dialyze by themselves, without "supportive family members" to help.

In Australia and New Zealand, as many as 50% of patients dialyze at home, about 35% with PD and 15% with HD. In the US, fewer than 8% of people dialyze at home. Americans are not fundamentally different from Australians--but our healthcare system is.

According to the Dialysis Outcomes and Practice Patterns Study (DOPPS), the US has the poorest dialysis outcomes in the industrialized world, due in large part to short, thrice weekly treatments that are inherently unphysiologic. Kidneys maintain homeostasis. Standard dialysis as it is practiced in the US offers precisely the opposite. If we set out to develop a treatment designed to make people with kidney failure feel their worst, we'd choose 3x/week 3-hour treatments.

[Miriam Lippel Blum]

Well said, Dori. But how much poorer the dialysis companies would be (said with great sarcasm.)

[Dori]

Miriam, when working-age people on dialysis (who are 50% of the total) feel well enough to keep their jobs and their health plans, dialysis companies do BETTER, because they have more people with employer group health plans (EGHPs) that pay more than Medicare does. It improves their payer mix to offer PD, nocturnal dialysis in-center or at home, or short daily treatments. So, it's a win-win-win for patients, dialysis providers, and Medicare when people get better dialysis.

The real barrier to this, IMHO, is the "wall" between Medicare Part A (hospitalization) and Part B (outpatient services including dialysis). The renal community does not get "credit" for reducing hospitalization by offering better dialysis, so CMS has not yet routinely approved payment for a 4th dialysis treatment. In an integrated system like Kaiser Permanente in southern California, all of the incentives are aligned. With Medicare, they are reversed. This is just poorly constructed policy.

[Lana Shubina RN CNN]

My dialysis center opened In-Center Nocturnal Hemodialysis almost 3 years ago. Currently we have 18 patients who is coming to the unit 3 nights a week and getting 8 hrs long gentle slow dialysis. 60% of them are working full-time and feeling great after their treatments. Some of the older patients with poor cardiac status are not doing that well: they are feeling less energetic, often very tired after longer treatments. We still have few patients who continue to gain over 6kg between treatments. We use sequential UF, low sodium modeling (SVS 143 step) and ongoing education. All patients are reporting increased appetite and feeling less "drain" than after short dialysis sessions. Most of them are sleeping during the nights with or without sleeping aids, but few only have a short naps of 3-4 hrs and reporting that they have to go to bed at home after dialysis.
I think that Nocturnal In-Center Hemodialysis is one of the preferable treatment choices but not for everyone.

[Brian Steele-Sierk]

Heh- I ate two bowls of onion soup tonight, and am now hooking up to my nxstage.

The real is as stated- we assume in center as the "normal" treatment modality, rather than trying to find ways to get patients home.