Dialysis from the sharp end of the needle

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. 

Treatment Options for Intradialytic Hypotension

By Peter Laird, MD

The Renal Fellow Network is an excellent source of information on nephrology issues written by a doctor going through his own renal fellowship training. It has become a favorite part of my own day to catch up on what new and interesting topic he will discuss with one new topic devoted every day.

Yesterday's post is on treatment options for low blood pressure during dialysis sessions. This is a very common problem in American dialysis units, especially in those that treat with high blood flow rates, high flux filters and short dialysis times. He discusses several options for reducing these episodes during dialysis. From a technical point of view, they are useful adjuncts for treating patients subject to this complication, but he fails to discuss the most important aspect of intradialytic hypotension, why it happens in the first place.

Thus, I take issue with his response from three separate arenas. First, he does not address the most important factor which is dietary salt control in those patients that end up needing higher ultrafiltration rates to maintain their stated dry weight. Preventing the need for higher ultrafiltration rates encumbered by elevated sodium intake should be number one on the list for treating what is a chronic complication in many dialysis patients as Bill and Anna have recently commented on (here and here).

Reviewing all of his remedies for low blood pressures during dialysis we see once again the American bias to problems caused by an inadequate level of dialysis in the first place. Longer dialysis sessions in Europe, Japan and Australia avoid most of America’s complications caused by our unique rapid ultrafiltration rates during short sessions of 2.5 - 3 hours that most patients are subjected to. Simply lengthening the same fluid removal over a longer period of time will eliminate the majority of hypotensive events caused by this overly aggressive approach to dialysis.

With over forty years of observational studies in America and around the world, it's our short and fast paced dialysis regimens that should be a prime suspect for causing our last place ratings internationally. The US's poor CKD5 outcomes should challenge all American nephrologists to reexamine what can only be judged an unsuccessful approach. Yet, with this short treatise on intradialytic hypotension, it appears that those in training today still have not grasped the underlying causative factors leading to these hypotensive events in the first place. Why treat a complication that could be avoided in the first place?

Second, the entire issue of intradialytic hypotension is intertwined with the elevated risk of LVH/CHF due to issues of blood pressure control as well as elevated interdialytic fluid weight gains. The long term effects of poor fluid control leads to LVH and subsequent increased risk of sudden cardiac death. The European, Japanese and Australian first line remedy for this is to increase frequency of dialysis above 3.5 times per week, or increase the total weekly duration with a concomitant reduction in blood pump speed and ultrafiltration rate. Once again, comparing the American approach as found in this short treatise in the Renal Fellows Network to that of our colleagues overseas, we do not find a single remedy that will improve the longevity of the patients that they are caring for while quotidian dialysis regimens will.

Lastly, quotidian dialysis regimens in whatever form completely eliminate intradialytic hypotension for all practical purposes. Although I do enjoy the materials that this nephrologist in training presents on his site and I value greatly all that I learn from his efforts, I am also equally appalled by the complete avoidance of dialysis related issues that we have learned from our international colleagues. While I would give most of his articles very high marks, the current article on intradialytic hypotension falls short by failing to correlate causative factors with long term treatment options shown to eliminate this problem in the first place as we have learned from the many articles on quotidian dialysis.

It is time for American nephrology programs to take notice of the simple truths of those that keep their patients alive longer than we do here in America. Intradialytic hypotension is a direct complication of rapid, violent fluid removal by short and high intensity dialysis regimens especially in the frail and elderly patient with LVH from chronic fluid overload. It is time to mellow out and slow down our dialysis protocols and then every single remedy listed in the article in question would never need to be considered at all since the problem would no longer exist except on rare occasions. Until American nephrologists recognize that many of the usual complications of dialysis are actually caused by our failed approach to dialysis, we will continue to chase our tails treating that which we should instead prevent.

No, really. People with CKD (actually everyone) should not eat a lot of salt

By Bill Peckham

RenalWEB links to an interesting announcement from the American Society of Nutrition Salt reduction may offer cardioprotective effects beyond blood pressure reduction. There is a lot of research that tells us controlling salt is an important part of living with CKD. This research from the American Society of Nutrition that "salt reduction may offer cardioprotective effects beyond blood pressure reduction" is not specific for people with CKD it is a recommendation for everyone.

For people with CKD controlling salt is even more important. This year World Kidney Day on March 12th is being held in collaboration with World Hypertension Day on May 12. The reason for this collaboration is that the vast majority of people with early stages of CKD will die prematurely before they progress to needing renal replacement. This is due in large part to poor cardiovascular health. Everyone with CKD, without exception, needs to protect their cardiovascular health. Controlling salt intake is an important tactic in this fight. The sponsors of World Hypertension day, the World Hypertension League (I hope they all wear jump suits with rank designation patches) have compiled a lot of research into how everyone, including everyone with CKD, can protect their cardiovascular health.

The paper relevant to salt A Dash of Salt and Tone: Recent trials providing new insights into the diet-blood pressure healthlink, makes it clear that control of salt intake is an important part of a healthy diet and  "individuals typically considered to be at the highest risk for hypertension and cardiovascular events, the elderly and African-Americans, had the greatest reduction in blood pressure with these dietary alterations." Simple "dietary interventions consisting of reduced salt intake and increased use of fresh fruits, vegetables and low-fat dairy products" go a long way to a healthy heart. It's a great idea for a partnership and the people running the World Kidney Day effort should be applauded for this year's focus on cardiovascular health.

So it was with great dismay that while wandering cyberspace I came across this recipe in the Kidney Support Network's Xmas 2008 newsletter (pdf link). Per serving: Sodium (mg) 1530; Potassium (mg) 945; Phosphorus (mg) 370. 1530mg of Sodium per serving! I think the World Hypertension League would judge Devilled Sausages & Creamy Garlic Mash unfit for human consumption (to the Pressuremobile team!).

That's just ridiculous. I wrote to the Kidney Support Network:

I was looking through your newsletter - I would like to know more about your organization. For instance some details about the hemodialysis van that is available, I think that would be a great thing to make available here in the NW United States.

But I was SHOCKED and ALARMED by the recipe included in your December newsletter: Xmas Edition 2008 1530 mg of salt per a serving!?! That would be dangerous for people without kidney problems; for people with kidney problems it is without any doubt contraindicated. Salt causes thirst.

Eating one serving of Deviled Sausages & Creamy Garlic Mash would create a thirst that could only be satiated by drinking far too much fluid. People on dialysis must not eat this dish.

Hypertension is a leading cause of stage 5 chronic kidney disease. A diet high in salt can exacerbate hypertension. One serving of Deviled Sausages & Creamy Garlic Mash would very nearly use up a person's day allotment of sodium.

See the abstract Low sodium diet for dialysis patients: myth or reality?, talk to your own Dr. Agar to the south or believe the Rigby, Scribner, Ahmad's paper from 2001  Interdialytic fluid weight gain is mainly caused by sodium intake which makes the rather obvious point again that sodium intake drives thirst

For the sake of your community's health you must redact the recipe from the newsletter at once. And I would suggest rather than getting your recipes from Nestle Australia you should instead ask for permission to take recipes from "Cooking Without a Grain of Salt" available on Amazon.com

Reading it now, after sleeping on it, I would have written it differently but the reply I received makes it clear that it wasn't a mistake. That they do, in fact, think of Devilled Sausages & Creamy Garlic Mash as food for humans:

I hear and understand your concerns about the salt content in the recipe, however it  wasn’t just from Nestle for the general public as I think you have assumed, it was from a site specifically for kidney patients and was checked by dietitians who are our contacts here locally (here in Australia) prior to publishing it. From memory the recipe came from an American site DaVita, as we had to seek their permission to publish, but I will look into it further.

One of the unfortunate issues with diets for kidney patients is that they are all different – and there are very few recipes suitable for everyone. Some people have the fluid restrictions you speak of and others do not, some have to watch protein intake and I have heard of others who are put on high protein diets. It is extremely difficult for generalizations and what we encourage is everyone to do is to educate themselves on what they are able to consume based on their illness and treatment and monitor their health appropriately.

Okay it is true that some small number of people who are on dialysis and still have urine output do not have to strictly control their fluid, most are those who's CKD is due to PKD. I had some fluid output for the first four years of dialysis but that is a poor reason to hang your argument on because the relative numbers are small. The recipe is not healthy and it is particularly unhealthy for people with no renal function who the organization is dedicated to serve. Come on. 945mg of Potassium!

I never got past the sodium to notice the potassium until writing this post. This recipe is dangerous. If someone has this on the first night of their dialysis weekend and then has leftovers they could easily end up in the hospital or in the ground. Go ahead and keep in mind the varied needs of people with CKD but that should not conflict with offering only healthy menu ideas.

And no, the recipe did not come from DaVita, I will eat this blog if a DaVita dietitian signed off on this salt and fat concoction. It is beyond all belief that DaVita would shill for Maggi's little balls of death or whatever it is the recipe calls for. Google says the only other place the recipe shows up is on Nestle New Zealand. World Kidney Day is coming, let's all try to eat a healthier diet, a diet without a lot of salt. It's a simple way for everyone to live healthier and for people with CKD it is doubly important.

Delaying the onset of CKD5 through implant

Renal Business Today links to a story from The Mail online Tiny pump which could boost kidney patients' lives:

The idea is the new implant would be used before patients deteriorate to the stage where they need dialysis.

By boosting the rate at which blood flows through the kidneys, it's hoped it will speed up the removal of waste products and fluid.

The treatment - which is being developed by Nephera Ltd, an Israeli firm, and has been tested in animal studies - could mean many dialysis patients are free to carry on with their daily routine.

This approach of getting the most out of existing kidneys sounds very promising. Anything that can slow the progression of people to CKD5 creates great savings - money and misery - for all concerned.

Genetic testing won't keep you off dialysis

by Anna Bennett

In 1994, the gene for polycystic kidney disease was discovered. Although there was a huge buzz in the PKD world about it, I was uncharacteristically unfazed. I am second generation ADPKD. My mother was in CKD-3 when she gave birth to me in 1966, and twelve years later, she was in full blown CKD-5 with no option for dialysis. She died when she was 44.

I knew that I had ADPKD, I had know all of my life. When I was a child, I had genetic counseling, so I had already made the conscious decision to not have children. I was well educated in lifestyle choices to minimize the impact of the rapidly growing cysts in my body, my medical status was frequently reviewed and well documented, I was an ADPKD poster child and I already had the roadmap for my future. I didn’t feel the need for genetic testing.

But some people do, and I recognize that. The Human Genome Project has an online reference page for those who are researching genetic testing. This is not a test that someone should take lightly, in these days of electronic archives, lawyers rewriting medical policy and procedures, and the industry reeling from spiraling insurance and healthcare rates. Documentation that (even though you may be asymptomatic) you have a potentially deadly genetic disease, could be an economic as well as physical black cloud in your or your child’s life. When I was 25 and asymptomatic, my life insurance was denied – based on PKD being in my medical chart. I was in peak health, and I couldn’t buy life insurance.

The Council for Responsible Genetics has an online position paper on genetic discrimination. I think that this should be a must read for anyone considering genetic testing. Congress has passed a bill the Genetic Information Nondiscrimination Act of 2008, HR493.  This is a beginning, because we not only have to consider our health, but we also need to consider our civil rights.

NDT slaps down AIM over Vitamin D use in dialysis

RenalWEB links to an April 2008 editorial in Nephrology Dialysis Transplantation which is in response to a meta study and editorial published in the December 2007 in Annals of Internal Medicine.

This is about Vitamin D. The gist is that this meta study, a survey of all the data (papers going back to 1966) does not demonstrate that vitamin D works. The AIM editorial finishes by saying

Pending new evidence from randomized trials, decision makers, physicians, and payers should consider modifying practice guidelines, prescribing patterns, and reimbursement policies [for vitamin D] to reflect the current state of evidence.

This is a serious recommendation which would impact the provision of dialysis here and around the world. NDT steps up to the challenge though and in a really nice way says "You don't know what the hell you're talking about", or at least that's how I interpreted the editorial response. In blog terms it is a thourough Fisking of the AIM editorial. NDT finishes

we strongly disagree with the latter statement [quoted above]: It is absolutely not advisable to withhold the hormone, vitamin D, from dialysis patients, who are severely depleted of vitamin D. This recommendation is potentially dangerous!

Good for NDT. We need more push back on these headline grabbing over-reaches. Again, this points up the need for dialysis research. Dialysis has numerous unanswered questions. Fundamental unanswered questions. We need dialysis research that is independent of the renal pharmacy industrial complex and we need it soon. And in great quantity.

Dialysis blood pump speed and fistula health: Is there a connection?

Home Dialysis Central's topic of the month is by the good Dr. Agar who surveys the literature on the impact of dialysis blood pump speed on the fistula and secondly on heart health. This has been a topic of personal concern. When I first started connecting with the dialysis community on the internet and traveling/dialyzing in Europe the consensus opinion was that slower speeds were better - I asked for my blood pump speed (Qb) to be lowered to 350ml/minute even though it meant lengthening my treatments.

Generally, it seemed that Qb was slowing until the System One came out and again Qb was at the center of the discussion. With the NxStage the length of the treatment is directly tied to Qb - the slower Qb the longer the run. For the first time I was hearing about Qb > 500 - 600Qb! Was this higher Qb bad in itself, opinions differed.

Dr. Agar looks at the data and finds a lack of information. Ultimately the answer is maybe, no one really knows. Dr. Agar suggests that the lower flows between the needles could cause clotting issues and the greater turbulence at the venous needle could create issues but Dr. Agar wants hard data and there is none. He is left to go back to first principals:

Perhaps other effects may result, though. Here, I go back to my views about the harmful effects of shorter, more "gung-ho" dialysis. The short treatments made possible by raising the pump speed, in my view, yield poorer dialysis and to worse health and lower survival.

Now that I am dialyzing overnight at a 250Qb I'm on the side of the angels but the question remains - what, exactly, is the impact of high Qb? This is another call for basic dialysis research.

Free issues of peer reviewed magazines

RenalWeb links to Blackwell Synergy who has made one issue of three renal related magazines freely available:

• The January/February 2008 issue of Seminars in Dialysis, including these articles:
  • Editorial - The Optimal Hemoglobin in Dialysis Patients— A Critical Review
  • Opinion - five nephrologists answer: What Are the Problems with Using the Peritoneal Membrane for Long-Term Dialysis?
  • Special report - Dialysis Surveillance Report: National Healthcare Safety Network (NHSN)—Data Summary for 2006
• The January 2008 issue of Hemodialysis International, including these articles:
  • Special Article: Longer and better lives for patients … and their centers: A strategy for building a home hemodialysis program
  • Scholarly Review: Health-related quality of life in the era of erythropoietin
  • Original Articles: Dialysis adequacy and nutritional status of hemodialysis patients
• The February 2008 issue of Nephrology, including these articles:
  • Progressive Chronic Renal Disease: The third World Kidney Day: Looking back and thinking forward (Editorial)
  • Dialysis: Micronutrient deficiency in chronic kidney disease (Editorial)
  • Transplantation: Acute renal allograft rejection is associated with increased levels of vascular endothelial growth factor in the urine

These articles can get thick. For instance from Hemodialysis International: "Oral intake during hemodialysis: Is there an association with intradialytic hypotension? " would sound more familiar once it is translated: "Eating during dialysis - does it cause low blood pressure?" If you can get past all the unneccessary polysyllabic words there is a lot of good information in these three issues.

Wearable peritoneal dialysis device

This is an interesting patent for an artificial kidney dialysis system, which in fact combines waste removal and "an implantable fluid removing device". It seems to propose to use the sort nanoengineered dialysis membrane that Dr. Steinman described in video two of the CIMIT presentation. They use the phrase "another embodiment" often in the filing which I take to mean that this is in the early stages.

I was interested because I had not considered peritoneal dialysis as a way to make wearable dialysis practical. The nanoengineered filters cleanse the dialysate not the blood directly. This eliminates the blood access issue which I think is wearable hemodialysis's biggest challenge. Wearable peritoneal sounds more practical.

It's also interesting to consider the advantages of an implantable device that removes only fluid. I wonder if such a device could be used temporarily to get people to their dry or to eliminate the need for fluid control. Dialysis would be much less of a burden if people did not have to remove fluid. It's the buildup and rapid removal of fluid that causes the heart so much stress. Continuous fluid removal would make blood pressure control less complicated.

Rather than trying to match a kidney feature for feature, maybe the best approach is an incremental approach. First create an internal device to remove water only while, the current technology is used to cleanse the blood.