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Dialysis Discussion => Dialysis: News Articles => Topic started by: okarol on January 10, 2014, 12:06:21 AM
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NxStage Gaining Ground On Growing Adoption Of Home Hemodialysis
Jan. 7, 2014 12:33 PM ET | 4 comments | About: NXTM
Disclosure: I have no positions in any stocks mentioned, and no plans to initiate any positions within the next 72 hours. (More...)
NxStage Medical (NXTM) is a medical device company in the dialysis therapy market that develops, manufactures and markets innovative products for the treatment of kidney failure, fluid overload and related blood treatments and procedures. It is a smaller company in the market compared to established players, such as Fresenius (FMS) and DaVita (DVA). These two companies account for more than half of the conventional dialysis market segment in the United States. However, NxStage Medical's System One is currently the only portable system specifically indicated for use in the home hemodialysis market segment in the United States.
NXTM debuted in the stock market in late 2005. In 2011 NXTM crossed $25 before witnessing a secular downtrend in the next two years. In 2013 the shares of the company offered flat returns to investors. NXTM introduced home-based hemodialysis solutions in an immature market with limited adoptions. As a result, the company could never deliver positive earnings since its IPO. However, over the past few years the market has gradually become mature with adoption picking up slowly but steadily. I believe this year could be a blockbuster for the company with increasing demand for its System One home-based hemodialysis equipment.
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What Does NxStage Do?
NxStage operates in two segments, System One and In-Center. Its primary product, the NxStage System One, is a portable hemodialysis system designed to satisfy an unmet clinical need for a system that can deliver the therapeutic flexibility and clinical benefits associated with traditional dialysis machines in a smaller, portable, easy-to-use form that can be used by healthcare professionals as well as trained lay users in a variety of settings, including patient homes, hospitals and dialysis clinics.
The System One is approved for sale in the United States, Canada and certain other markets for the treatment of acute and chronic kidney failure and fluid overload. The company also obtained CE mark to sell the product in the European Union for treating the same diseases. The FDA has approved System One specifically for home hemodialysis as well as therapeutic plasma exchange ("TPE") in a clinical environment.
The company also sells a line of extracorporeal disposable products, such as needles and blood tubing sets, primarily for in-center dialysis treatments for patients with end-stage renal disease ("ESRD"). However, the company's largest market opportunity is for its System One equipment used in the home dialysis market for the treatment of ESRD.
NxStage Offers An Excellent Product
NXTM's innovative approach to treat renal care is creating significant opportunities for the company. Its home-based hemodialysis device System One, as mentioned above, has been designed to enable patients to perform hemodialysis on a daily basis in their homes, using simple plumbing and standard electrical connections. Its easy-to-use drop-in cartridge allows for easy and wipe-down disinfection after each use. See what the Clinical Kidney Journal ("CKJ") says about System One:
It embodies new concepts in dialysis machine design. Dialysis fluid is lactate based (like CAPD fluid) and flows are reduced to ∼120 mL/min while high blood flows are maintained. The efficiency of small solute clearance is thus maximized and approximates the volume of fluid used. The design is modular and the footprint is small, similar to that of an automated peritoneal dialysis ("APD") machine, which it resembles. Dialyser and lines are provided in a cartridge to simplify set-up and clean. For home use, a dialysate preparation system is used which is also cartridge based, thus avoiding the need for extensive building and plumbing work and to reduce the volume of fluid storage that can be problematic in peritoneal dialysis. The machine is portable and, when traveling, utilizes bagged dialysis fluid. Short daily dialysis is the standard mode, but nocturnal treatment, say, every other night, is also supported.
The primary advantage of System One lies in its frequent use in home hemodialysis therapy by dialysis patients who are seeking freedom, increased energy, and logistical benefits. Clinical data suggests that hemodialysis therapy administered five or six times per week, commonly referred to as more frequent therapy, better mimics the natural functioning of the human kidney and can lead to improved clinical outcomes, including lower mortality and improved survival, significant improvements in left ventricular mass, reductions in antihypertensive medications, reduced fluid overload, reduced depression and improvements in health-related quality of life.
ESRD is an irreversible, life-threatening loss of kidney function that is treated predominantly with dialysis, an essential therapy that removes toxins and excess fluids from the bloodstream. Unless a patient receives a kidney transplant, dialysis is required for the remainder of the patient's life. The most widely prescribed type of dialysis is hemodialysis, which typically consists of treatments in a dialysis clinic three times per week. ESRD affects over 550,000 people in the United States and 2 million people worldwide. Approximately 8% of the ESRD patients in the United States receive some form of dialysis treatment at home, most of whom are treated with peritoneal dialysis. Hemodialysis and peritoneal dialysis are both used to treat kidney failure. The difference is that hemodialysis uses a man-made membrane (dialyzer) to filter wastes and remove extra fluid from the blood, while peritoneal dialysis uses the lining of the abdominal cavity (peritoneal membrane) and a solution (dialysate) to remove wastes and extra fluid from the body.
Adoption Not Impressive, But Outlook Is Changing
Despite the fact that nocturnal home hemodialysis ("NHHD") can significantly improve patient health outcomes compared to conventional hemodialysis ("CHD") at health care institutions, the adoption of NHHD remains limited. Findings from various studies within the industry have shown that compared to CHD, self-care NHHD can lead to important health improvements in:
• Dialysis Adequacy / Effectiveness
• Survival / Mortality
• Anemia Status
• Blood Pressure
• Hospitalization Rates
• Fluid and Dietary Restrictions
• Prescription Drug Use
If the benefits of NHHD were just what the above list specifies, it would still be considered as a remarkable therapy option. But in practice, NHHD leads to an overall improved quality of life, including enhanced energy, improved appetite, sleep quality and sexual function, and increased rate of employment.
To understand why NHHD has not been widely adopted despite these huge benefits, a study was conducted by the researchers from the University Health Network and the University of Toronto. The study concluded that various patient-perceived barriers, such as fears of self-cannulation, a catastrophic event, and unknown burden on the patient's family, are responsible for the limited adoption of NHHD.
If this is bad news, the good news is that physicians and researchers are now increasingly trying to educate patients and their family members about the benefits of self-care home-based hemodialysis and associated hazards. It is expected that within a short span of time they would be able to fully convince the patient community the benefits of NHHD and impart necessary knowledge for its adoption.
Zero Competition
In addition to NxStage, Fresenius has also developed its own home-based hemodialysis system, apart from offering its customers the NxStage System One equipment. The most significant competitive advantage of System One over Fresenius' 2008K@home system is that it offers patients the freedom to travel and dialyze on the road or dialyze throughout their home. The 2008K@home is a simplified home-based machine, which offers visual support through step-by-step setup and treatment tutorials. The machine includes a wireless wetness detector and alarm, the "Diasafe Plus" filter to eliminate contaminates, and remote monitoring and data capture. But unfortunately the 2008K@home system does not offer portability.
Risk Versus Reward
The balance sheet of NXTM has no apparent weakness. The company is cash-rich with cash and cash equivalents of $83 million as of the third quarter of 2013. Cash burn is not alarming; in the third quarter cash burn was $11 million and included $5 million of capital expenditures associated with its manufacturing operations and its centers of excellence and approximately $2 million associated with the acquisition of its home business in the UK. Moreover, the company has no significant debt.
With a fairly robust balance sheet in hand, let's assess the risk-reward profile of the company.
Risk
The first risk is that NXTM is not yet profitable even after eight full years of existence. The company's full-year 2013 revenue is expected to be within the range of $261 to $262.5 million and net loss within the range of $19.5 to $18.5 million, or ($0.32) to ($0.31) per share.
NXTM depends heavily on two of its customers, which I feel is another risk associated with the company. Currently DaVita and Fresenius are two of NXTM's largest and most significant customers in the System One segment. Direct sales to DaVita represented 31%, 31% and 34% of its System One segment revenues during 2012, 2011 and 2010, respectively. Further, DaVita constitutes over 40% of its home hemodialysis patients. Direct sales to Fresenius represented 17%, 14% and 10% of the company's System One segment revenues during 2012, 2011 and 2010, respectively.
In my investment thesis, I assume that NXTM would soon become a profitable entity. In fact, this is what the thesis is based on. The purpose of the discussion I presented above is to establish that there is a very good chance that NXTM would soon become EPS positive with its System One equipment.
It is no myth that the benefits of home-based hemodialysis far outweigh the risks associated with it. Currently the most widely adopted form of dialysis therapy used in a setting other than a dialysis clinic is peritoneal dialysis. With physicians and researchers beginning to understand the benefits of more frequent home-based hemodialysis therapy at a significantly lower cost, which only System One can provide compared to its competitors offering peritoneal dialysis or conventional hemodialysis, I believe NXTM would seize a meaningful market share from its competitors in the treatment of ESRD. NxStage believes that approximately 10-15% of the over 385,000 ESRD patients in the United States currently receiving dialysis treatment would be appropriate candidates for home hemodialysis with the NxStage System One. This represents a huge opportunity that the company could tap with its System One device.
Reward
NXTM's long-term growth depends on the number of patients who adopt home-based hemodialysis and how quickly they adopt it, which in turn is driven by the number of physicians willing to prescribe home hemodialysis and the number of dialysis clinics able or willing to establish and support home hemodialysis therapies. If the company can convince the physician community and dialysis clinics by successful sales promotion, I estimate that the annual revenue of the company would cross $500 million within FY2015. If the industry average EBITDA margin of 17% is applied on the estimated revenue figure, NXTM's EBITDA would cross $85 million by FY2015. Now if we assign the industry average EV to EBITDA of 10x on NXTM's EBITDA, we can expect that its enterprise value will cross $850 million, currently which is $561 million. Let's add another $100 million of cash on that figure, and we get $950 million as the company's market cap, which translates into approximately $15.59 per share of NXTM. That represents ~50% upside from the current level around $10.50. I believe this could be a reasonable reward against a slim risk associated with the time frame when NXTM would become profitable.
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Conclusion
I have no doubt in my mind that home-based hemodialysis will become the standard therapy one day, because it is very hard to ignore the benefits of self-care therapy in the treatment of ESRD. However, it is interesting to see how the industry matures, overcoming the various patient-perceived barriers.
http://seekingalpha.com/article/1932581-nxstage-gaining-ground-on-growing-adoption-of-home-hemodialysis
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As doctor and care partner to my wife , I am a big fan of Nxstage. I dont own any stock and remain with no financial ties to the company.
I do beleive their system has some big advantages over the competing Fresenius system for many patients . While portability is a plus, I feel the big advantage is the ability to do near daily dialysis which more closely mimics the actual kidneys. 5 days per week is a big improvement over 3 or 4 days per week. (6 would even be better). There is less build up of toxins and fluid and dialysis is less harsh and feels better.
The system is not perfect but is the best we have currently.
For anyone incenter now I would suggest trying a week or two on 5 days per week NxStage. Our clinic is offering that as a trial in center now. The first 2 patients just switched over to NxStage from in center as they felt so much better on Nxstage ,5 days per week. I always say the proof is in the pudding, and it has proved itself so far quite well. My wife is the first patient our clinic had on Nxstage and she also saw the huge improvement in how she felt switching over. She has been using it for a year and a half now.
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A huge NxStage risk (speaking from an investment, not a medical, perspective) is the Fresenius PAK (Portable Artificial Kidney). The PAK appears to be sorbent technology small system similar to NxStage, but reportedly capable of generating URRs on par with the conventional machines like the 2008K and BabyK.
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A huge NxStage risk (speaking from an investment, not a medical, perspective) is the Fresenius PAK (Portable Artificial Kidney). The PAK appears to be sorbent technology small system similar to NxStage, but reportedly capable of generating URRs on par with the conventional machines like the 2008K and BabyK.
I can't talk about the PAK due to 5 year NGA, but the NxStage System One upgrade to high flow is a substantial answer to that. From the RSI and noted by Dr. John Agar who is a medical advisor for the PAK, the dialysate is "near" ultra-pure while the NxStage reaches ultra-pure dialysate.
http://www.nocturnaldialysis.org/technology_whats_coming.htm
In my opinion, any system that is ultra-pure has significant benefits clinically for patients as documented in several studies. The NxStage will now get up to 300 ml/min dialysate which if you look at the dialysate flow curves, it is on the plateau section of the curve and approximates in-center clearances. Since this is now FDA approved, it is quite a significant improvement and rivals the other systems Since NxStage is FDA approved, the other machines are at a great disadvantage at present. I welcome the soon arriving competition in the market place among dialysis machine manufacturers, but it is still a ways off apparently. We will have to see how the new additions affect the market place.
I would not count NxStage out of the competition by any measure used.
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Nephron Clin Pract. 2013;123(3-4):246-53. doi: 10.1159/000354714. Epub 2013 Sep 4.
Effect of using ultrapure dialysate for hemodialysis on the level of circulating bacterial fragment in renal failure patients.
Kwan BC, Chow KM, Ma TK, Cheng PM, Leung CB, Li PK, Szeto CC.
Author information
abstract
Background: Cardiovascular disease is the major cause of mortality and morbidity in dialysis patients. Recently, circulating endotoxin is found to associate with the systemic inflammatory state and cardiovascular disease of dialysis patients. Previous studies showed that the use of ultrapure dialysate for hemodialysis could reduce the exposure to exogenous endotoxin. We studied the effect of using ultrapure dialysate for hemodialysis on circulating endotoxin and bacterial DNA fragment levels and vascular stiffness. Methods: This is an open-labeled prospective study of 25 patients (14 male). Circulating endotoxin and bacterial DNA level, vascular stiffness as represented by arterial pulse wave velocity (PWV), nutrition and hydration status were monitored before and repeatedly throughout 12 months after the use of ultrapure dialysate for hemodialysis. Results: The average age was 58.9 ± 10.2 years; 21 patients completed the study. Within 4 weeks of conversion to ultrapure dialysate for hemodialysis, the plasma endotoxin level fell from 0.302 ± 0.083 to 0.209 ± 0.044 EU/ml (p < 0.0001) and then remained static, while serum bacterial DNA level remained similar. Furthermore, the time-averaged plasma endotoxin level during the study period significantly correlated with serum C-reactive protein level (r = 0.483, p = 0.017), carotid-femoral PWV (r = 0.455, p = 0.033), and malnutrition inflammation score (r = 0.461, p = 0.031). The time-averaged serum bacterial DNA level significantly correlated with malnutrition inflammation score (r = 0.550, p = 0.008) and inversely with subjective global assessment score (r = -0.543, p = 0.009), but not with PWV. Conclusions: In hemodialysis patients, circulating endotoxin level is associated with vascular stiffness and systemic inflammation. Using ultrapure dialysate for hemodialysis effectively reduces circulating endotoxin level in hemodialysis patients. The long-term benefit of using ultrapure dialysate for hemodialysis requires further study. © 2013 S. Karger AG, Basel.
PMID: 24008429 [PubMed - in process] Free full text
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Hemodial Int. 2010 Jan;14(1):39-46. doi: 10.1111/j.1542-4758.2009.00399.x. Epub 2009 Sep 16.
Solute kinetics with short-daily home hemodialysis using slow dialysate flow rate.
Kohn OF, Coe FL, Ing TS.
Author information
Abstract
"NxStage System One()" is increasingly used for daily home hemodialysis. The ultrapure dialysate volumes are typically between 15 L and 30 L per dialysis, substantially smaller than the volumes used in conventional dialysis. In this study, the impact of the use of low dialysate volumes on the removal rates of solutes of different molecular weights and volumes of distribution was evaluated. Serum measurements before and after dialysis and total dialysate collection were performed over 30 times in 5 functionally anephric patients undergoing short-daily home hemodialysis (6 d/wk) over the course of 8 to 16 months. Measured solutes included beta(2) microglobulin (beta(2)M), phosphorus, urea nitrogen, and potassium. The average spent dialysate volume (dialysate plus ultrafiltrate) was 25.4+/-4.7 L and the dialysis duration was 175+/-15 min. beta(2) microglobulin clearance of the polyethersulfone dialyzer averaged 53+/-14 mL/min. Total beta(2)M recovered in the dialysate was 106+/-42 mg per treatment (n=38). Predialysis serum beta(2)M levels remained stable over the observation period. Phosphorus removal averaged 694+/-343 mg per treatment with a mean predialysis serum phosphorus of 5.2+/-1.8 mg/dL (n=34). Standard Kt/V averaged 2.5+/-0.3 per week and correlated with the dialysate-based weekly Kt/V. Weekly beta(2)M, phosphorus, and urea nitrogen removal in patients dialyzing 6 d/wk with these relatively low dialysate volumes compared favorably with values published for thrice weekly conventional and with short-daily hemodialysis performed with machines using much higher dialysate flow rates. Results of the present study were achieved, however, with an average of 17.5 hours of dialysis per week.
PMID: 19758296 [PubMed - indexed for MEDLINE]
MeSH Terms, Substances
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The NxStage will now get up to 300 ml/min dialysate which if you look at the dialysate flow curves, it is on the plateau section of the curve and approximates in-center clearances.
Thanks for the information. I am on the BabyK EOD (though usually 4 days a week, Tues/Thurs/Fri/Sun) and my last URR was 76%. The Rn tells me their URR goal on NxStage is 40% for a 5 day patient, 38% for a 6 day patient. What URR is the high flow NxStage getting that "approximates" in-center clearance. If I can get something approximating the BabyK, it may be worth a switch.
Also, do you have any thoughts on the Fresenius 5008 hemo diafiltration system? (www.highvolumehdf.com)
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My wife gets 63% URR on 5 day per week NxStage at 30 liters dialysate. It is just about the same as in center now. If we needed better clearance we could raise the amount of dialysate. We dont run that fast either. Blood flow 340 , dailysate 10 liters per hour.
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My wife gets 63% URR on 5 day per week NxStage at 30 liters dialysate. It is just about the same as in center now. If we needed better clearance we could raise the amount of dialysate. We dont run that fast either. Blood flow 340 , dailysate 10 liters per hour.
How long do her 30 liter runs take?
I am going to try to arrange for a test run on the NxStage w/labs to see what sort of URR I get on the kind of treatment my doc would prescribe.
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We do 3 hours . It can be done faster or slower based on settings on machine. There is some flexibility.
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We do 3 hours . It can be done faster or slower based on settings on machine. There is some flexibility.
You are doing a great job of getting me interested in NxStage. I've been told to expect 45% URR with 3 hours; you are seeing 63%. I'm going to ask for pre/post BUN labs with my test drive so I see what I get. Thanks for the info.
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We do 3 hours . It can be done faster or slower based on settings on machine. There is some flexibility.
You are doing a great job of getting me interested in NxStage. I've been told to expect 45% URR with 3 hours; you are seeing 63%. I'm going to ask for pre/post BUN labs with my test drive so I see what I get. Thanks for the info.
URR all depends on how much you weigh and how much dialysate volume used. However, America spends way too much time focussing on URR and Kt/V which really have little to do with real dialysis optimization.
If you are going to the NxStage, avoid the American style dialysis philosophy that I am sure the trainer will tell you. Run the blood pump as fast as you can and crank it up to 500 ml/min if you can so you can get done as quickly as you can. That is just wrong if you wish to live longer.
Japan has the best outcomes and they have URR and Kt/V's far below those of the US. Total time on dialysis is by far a more important parameter to consider.
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I am pushing my doc to let me go nocturnal, but he says that has to wait until Fresenius has real time monitoring in place - which is supposedly "soon".
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I am pushing my doc to let me go nocturnal, but he says that has to wait until Fresenius has real time monitoring in place - which is supposedly "soon".
The America experience is sadly vastly inferior to many nations such as Canada just to the north. Nocturnal dialysis, extended dialysis with no partner is quite common. I guess with 1/4 of the world's lawyers, we will remain a backwoods dialysis provider to our patients in America for quite some time.
Bill Peckham dialyzes home alone and all he has is a medic alert alarm. With Nocturnal, you run so slowly that problems with access and issues with the machine are not common as long as you tape up and hook up correctly. I am not the least bit happy with FMC at present. I wish you luck getting the care you need. At least you have a nephrologist who is willing to go the nocturnal route. Time is the most important factor due to middle molecule clearances.
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I agree with Hemodoc on time on machine. I would suggest trying to get the most dialysate you can approved for Nxstage and run it slower like we do . That way you can get more time on machine if you can manage it. We run our blood at only 340 and are now slowing down the dialysate a bit (down to 9.6) too to get more time on machine. The other key is number of days on the machine. The more the better. We do 5 days and some do 6 days . Others only do 4.
If you look at another way of calculating dialysis adaquacy put out a few years ago, it takes the number of days per week squared times hours per day. A "good adaquacy"would be around 60 to 80 and higher. If for example you do 5 days for 3 hours per day you get 5 squared times 3 which equals 75. That would be considered good dailysis. Standard in center is only 3 times per week for about 4 hours which gives a number of 36 which is poor dialysis.
So Nxstage helps with that formula as dialyisis frequency is a big factor in the calculation. By upping from 4 days to 5 you get a big jump in the calculation. 4 days squared times 3 hours only gives 48 which is fair dialysis only.
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If you look at another way of calculating dialysis adaquacy put out a few years ago, it takes the number of days per week squared times hours per day. A "good adaquacy"would be around 60 to 80 and higher.
By that measure, I'm hitting 60 exactly.
One thing that is frustrating about treatment is the widespread acceptance of mediocrity from even the so called "good" doctors. Patients on 3x/in center are not even told how woefully inadequate the treatment is. I'm on "conventional home" and I believe I would be on 3x rather than EOD if I had not brought the subject up with my doc - who was most supportive once I asked. Maybe there is an unwritten rule among docs "do not disrupt the status quo".
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Our big problem in the US is the vast majority of dialysis patients are on Medicare for insurance. Medicare only pays for 3 days per week dialysis. That means any one who dialyzes more is effectively costing the company money as they dont get reimbursed for the extra days. That is why we had to fight so hard at first to get our clinic to allow us NxStage. We do 5 days per week on NxStage and they only get paid for 3 days by Medicare.
The US lets the insurance (medicare ) basically set the standard for dialysis . Its backwards. The insurance should not be deciding what is medically neccessary for patients. Also once size fits all with medicare. Theyt pay the same number of days for each patient (3) and do not allow individualization. So the doctors are trained in the US with this standard. It becomes their default for patients. It is hard to break habits in many cases for more dialysis.
Dr. John Agar in Australia , a world renouned nephrologist, feels the US is very backwards(stone age) in our dialysis methods. We get far less time at far faster blood speeds then is best for patients. The faster blood speeds damage fistulas and can stun the heart. He beleives time is the key. It takes more time to get to the middle molocules and to deal with fluid compartments. We dont do enough time in the US.
That is one reason we chose NxStage. WE get more days and hours on the machine . It is gentler that way also.
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I'm hoping to see Nocturnal become more available. I had to move to a clinic 2.5 hours away in order to Nocturnal NxStage. That clinic's standard procedure is to run the blood pump at 400, which I did while using 60 liters of dialysate over 8 hours. I did 5 or 6 days a week (6 days is 288 using the above formula).
I believe one nephrologist up at the local hospital is trying to get in-center nocturnal and another is looking to get Nocturnal NxStage. I'm sure part of problem/delay is the Medicare issue. The new transplant surgeon told me that Nocturnal is the way to go. Maybe he'll have some influence to get the ball rolling...
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I'm hoping to see Nocturnal become more available. I had to move to a clinic 2.5 hours away in order to Nocturnal NxStage. That clinic's standard procedure is to run the blood pump at 400, which I did while using 60 liters of dialysate over 8 hours. I did 5 or 6 days a week (6 days is 288 using the above formula).
I believe one nephrologist up at the local hospital is trying to get in-center nocturnal and another is looking to get Nocturnal NxStage. I'm sure part of problem/delay is the Medicare issue. The new transplant surgeon told me that Nocturnal is the way to go. Maybe he'll have some influence to get the ball rolling...
Your blood speed is quite high, especially for nocturnal. The whole idea of nocturnal is to run SLOWER and gentler. Most patients in Australia run 225 nocturnal according to Dr. Agar. Running 400 puts a huge stress on the heart and fistula. Dr. Agar mentioned to me that 350 is the high end range he would consider and lower is better. We run 340 now and plan to try even slower.
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Dr. Agar is the global king of nocturnal dialysis, in my very humble opinion. My conversations with him have always been so incredibly enlightening.
Let's face it. Healthcare philosophy in the US has always been reactive as opposed to being preventative. What we don't seem to understand (or what Medicare doesn't understand) is that 3xweekly incenter dialysis causes expensive problems. What we think we save in dialysis costs we more that doubly spend on treating the problems that this modality causes. It's stupid.
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If you look at another way of calculating dialysis adaquacy put out a few years ago, it takes the number of days per week squared times hours per day. A "good adaquacy"would be around 60 to 80 and higher.
By that measure, I'm hitting 60 exactly.
One thing that is frustrating about treatment is the widespread acceptance of mediocrity from even the so called "good" doctors. Patients on 3x/in center are not even told how woefully inadequate the treatment is. I'm on "conventional home" and I believe I would be on 3x rather than EOD if I had not brought the subject up with my doc - who was most supportive once I asked. Maybe there is an unwritten rule among docs "do not disrupt the status quo".
This is the Hemodialysis Product by Belding H. Scribner, MD; Dimitrios G. Oreopoulos, MD.
http://www.therenalnetwork.org/qi/resources/HDP.pdf
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I'm hoping to see Nocturnal become more available. I had to move to a clinic 2.5 hours away in order to Nocturnal NxStage. That clinic's standard procedure is to run the blood pump at 400, which I did while using 60 liters of dialysate over 8 hours. I did 5 or 6 days a week (6 days is 288 using the above formula).
I believe one nephrologist up at the local hospital is trying to get in-center nocturnal and another is looking to get Nocturnal NxStage. I'm sure part of problem/delay is the Medicare issue. The new transplant surgeon told me that Nocturnal is the way to go. Maybe he'll have some influence to get the ball rolling...
If you run a blood pump speed of 400 ml/min for 8 hours, that is 192 liters of blood. Coupled with 60 liters of dialysate, your FF is then 31.25. For nocturnal, that is a very high blood flow rate. One of the advantages of nocturnal is the ability to turn down the blood flow rate and still gain the power of TIME for middle molecule clearance. America is stuck on fast, high volume, violent dialysis sessions that damage the fistula, the heart and the entire cardiovascular system.
Most programs around the world run around 250 ml/min blood pump speeds for nocturnal. Japan does that with just about all of their patients. The reason that they get better outcomes is that America is stuck on Urea clearances that clinically have very little relevance while the rest of the world understands well that TIME and FREQUENCY are the two most important factors of middle molecule solute clearances which is what also matters clinically. In other worlds, America is a backwards nation as far as dialysis issues are concerned.
I addition, when NxStage first entered the home hemodialysis market, they had a motto of "one liter of dialysate is one liter of clearance." What were they talking about? They introduced a "MARKETING" mantra that sounded good of utilizing 100% efficiency of the dialysate. That is fine as it sounds, however, in reality, it is just a gimmick since at the same time, the low FF which correlate directly with dialysate flow rates is remarkably low. What does this mean to the patient? Solute clearances under the old NxStage recommendations are remarkably below standard in-center solute clearances.
So no matter how "efficient" the dialysate is with these NxStage recommendations, the efficiency of one dialysis session is horribly low when you figure in TIME as a factor. For instance, I run an FF of 45% which translates into a dialysate flow rate of about 167 ml/min with a blood pump speed of 370 for 4.1 hours. My Kt/V is about 0.8 with this regimen.
In-center, I run a blood pump speed of 380 for 4.0 hours and my Kt/V was 1.2-1.4. NxStage is simply a low volume system that especially at 20 or 25 liters is actually in my opinion just too low.
I would highly recommend that you consider discussing with your medical team the benefits of lowering your BFR to the 250 level and increasing your FF to a level that will allow you to dialyze your 8 hours with the time exactly the same. That would be with a BFR of 250 ml/min a total of 120 liters of blood during an 8 hour session making 60 liters of total dialysis volume run at an FF of 50%.
The good news that I suspect your medical team is unaware perhaps is that the FDA approved a NxStage system upgrade in April that should change medical practice for ALL NxStage patients but has not had any real impact to date. In this, the NxStage System One highflow will now be able to run a dialysate flow rate of 300 ml/min or 18 liters/hour.
http://ir.nxstage.com/releasedetail.cfm?ReleaseID=760385
In your case, a BFR of 250 ml/min with an FF of 50% would result in a 125 ml/min dialysate flow rate for 8 hours. If your medical team still wishes to maximize your dialysate under the marketing mantra of "one liter of fluid is a liter of clearance," looking at the solute flow curves, you are still way under the 200 ml/min "max" rate under the old NxStage guidance. For your medical team, this means that they would not need to get the new upgraded high flow NxStage System One since the current machine would work just fine at 125 ml/min. (Remember, the FDA approval is for a new machine that exceeds the old machine by a factor of 200 ml/min on the old to 300 ml/min on the new upgraded version)
Once again, remember, that this was a sales pitch, not a clinical reality since the only thing that matters is what the patient sees not what the dialysate sees in efficiencies. It is now outdate by the updated FDA approval of high flow dialysate system and practices SHOULD change but haven't as of yet.
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Dr. Agar is the global king of nocturnal dialysis, in my very humble opinion. My conversations with him have always been so incredibly enlightening.
Let's face it. Healthcare philosophy in the US has always been reactive as opposed to being preventative. What we don't seem to understand (or what Medicare doesn't understand) is that 3xweekly incenter dialysis causes expensive problems. What we think we save in dialysis costs we more that doubly spend on treating the problems that this modality causes. It's stupid.
I believe it is more than stupid, I believe it is actually a calculated evil on the part of our government. I believe that they don't want long term survival on dialysis and that at about 36 months average survival for all dialysis patients, they save money by dialysis patients dropping dead despite the high hospital costs associated with this. I cannot prove this but there was an abstract at I believe the 2010 ADC that was from a Canadian province. They calculated that if dialysis patients improved survival, they would bankrupt their entire allotment for all patients. That is the closest I have heard of any studies or any government policies expressing what I believe is the underlying logic of "WHY" they allow the current situation to continue and actually augment this with their policy decisions at the CMS level.
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The good news that I suspect your medical team is unaware perhaps is that the FDA approved a NxStage system upgrade in April that should change medical practice for ALL NxStage patients but has not had any real impact to date. In this, the NxStage System One highflow will now be able to run a dialysate flow rate of 300 ml/min or 18 liters/hour.
I wonder how the economic practicalities will play out - there are a lot of 12 liter NxStage units out there, and I would expect that there would be some resistance to replacing all of these with 18 litre units, since either (a) NxStage will not be able to charge extra for this, thus creating an incentive for NxStage to limit availability, or (b) NxStage will be allowed to charge clinics extra, thus creating clinic level resistance.
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The good news that I suspect your medical team is unaware perhaps is that the FDA approved a NxStage system upgrade in April that should change medical practice for ALL NxStage patients but has not had any real impact to date. In this, the NxStage System One highflow will now be able to run a dialysate flow rate of 300 ml/min or 18 liters/hour.
I wonder how the economic practicalities will play out - there are a lot of 12 liter NxStage units out there, and I would expect that there would be some resistance to replacing all of these with 18 litre units, since either (a) NxStage will not be able to charge extra for this, thus creating an incentive for NxStage to limit availability, or (b) NxStage will be allowed to charge clinics extra, thus creating clinic level resistance.
NxStage has been seen as friendly to dialysis patients. However, in reality, they are a for-profit dialysis provider now that they are opening independent treatment units directly to patients. We will see soon the real character of this company and whether they are as "patient friendly" as they would like us to believe.
As far as getting the upgrade, good luck. I have been trying for 6 months myself already and I won't hold my breath waiting.
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I believe it is more than stupid, I believe it is actually a calculated evil on the part of our government. I believe that they don't want long term survival on dialysis and that at about 36 months average survival for all dialysis patients, they save money by dialysis patients dropping dead despite the high hospital costs associated with this. I cannot prove this but there was an abstract at I believe the 2010 ADC that was from a Canadian province. They calculated that if dialysis patients improved survival, they would bankrupt their entire allotment for all patients. That is the closest I have heard of any studies or any government policies expressing what I believe is the underlying logic of "WHY" they allow the current situation to continue and actually augment this with their policy decisions at the CMS level.
Oh, I so hope you are wrong!
I did not know that there are now NxStage clinics! Where are they, and when did they open? What do you think made them decide to become for-profit dialysis providers? That's interesting and unnerving at the same time.
We read a fair amount about the research that is going on where "ghost" organs are being created and where bits and pieces are being "built" using stem cells/pluripotent cells. It seems that we are getting closer to the day when dialysis as we know it will be obsolete (and, for that matter, transplantation). What do you see happening to those companies that make money off dialysis patients, the Davitas and the Fresenii of the world? Just hypothesizing and extrapolating from what you have seen and have experienced, how do you see the post-dialysis/post-transplantation world? What do you think such a world might look like financially?
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If you run a blood pump speed of 400 ml/min for 8 hours, that is 192 liters of blood. Coupled with 60 liters of dialysate, your FF is then 31.25. For nocturnal, that is a very high blood flow rate. One of the advantages of nocturnal is the ability to turn down the blood flow rate and still gain the power of TIME for middle molecule clearance. America is stuck on fast, high volume, violent dialysis sessions that damage the fistula, the heart and the entire cardiovascular system.
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I would highly recommend that you consider discussing with your medical team the benefits of lowering your BFR to the 250 level and increasing your FF to a level that will allow you to dialyze your 8 hours with the time exactly the same. That would be with a BFR of 250 ml/min a total of 120 liters of blood during an 8 hour session making 60 liters of total dialysis volume run at an FF of 50%
Your post makes complete sense. Why do you think America is so backwards on the dialysis issues?
I was on Short Daily NxStage for 16 months with a blood flow rate of 450! I used 20 liters of dialysate and my treatments were about 4 hours long. I learned about Nocturnal through IHD, so I was surprised when I switched over to Nocturnal and they wanted me to run at 400 BFR. I ran for about 2 months before having access issues, got an infection in the fistula, and had a chest catheter installed. Even the very experienced nurses have problems with my twisty, branchy, deep diving fistula. I successfully used the chest catheter at home for about 7 months before receiving a transplant on November 16, 2013.
I'd definitely talk to the dialysis team about this if I was still on dialysis. I was thrilled when my cycler left; unfortunately, I traded a known set of issues/time constraints for some serious side effects. :(
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I believe it is more than stupid, I believe it is actually a calculated evil on the part of our government. I believe that they don't want long term survival on dialysis and that at about 36 months average survival for all dialysis patients, they save money by dialysis patients dropping dead despite the high hospital costs associated with this. I cannot prove this but there was an abstract at I believe the 2010 ADC that was from a Canadian province. They calculated that if dialysis patients improved survival, they would bankrupt their entire allotment for all patients. That is the closest I have heard of any studies or any government policies expressing what I believe is the underlying logic of "WHY" they allow the current situation to continue and actually augment this with their policy decisions at the CMS level.
Oh, I so hope you are wrong!
I did not know that there are now NxStage clinics! Where are they, and when did they open? What do you think made them decide to become for-profit dialysis providers? That's interesting and unnerving at the same time.
We read a fair amount about the research that is going on where "ghost" organs are being created and where bits and pieces are being "built" using stem cells/pluripotent cells. It seems that we are getting closer to the day when dialysis as we know it will be obsolete (and, for that matter, transplantation). What do you see happening to those companies that make money off dialysis patients, the Davitas and the Fresenii of the world? Just hypothesizing and extrapolating from what you have seen and have experienced, how do you see the post-dialysis/post-transplantation world? What do you think such a world might look like financially?
NxStage has more than one I believe. Here is I think the first:
http://ir.nxstage.com/releasedetail.cfm?releaseid=797232
As far a FMC and DaVita, they are investing heavily in the new technologies. Don't expect them to disappear any time soon.
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If you run a blood pump speed of 400 ml/min for 8 hours, that is 192 liters of blood. Coupled with 60 liters of dialysate, your FF is then 31.25. For nocturnal, that is a very high blood flow rate. One of the advantages of nocturnal is the ability to turn down the blood flow rate and still gain the power of TIME for middle molecule clearance. America is stuck on fast, high volume, violent dialysis sessions that damage the fistula, the heart and the entire cardiovascular system.
....
I would highly recommend that you consider discussing with your medical team the benefits of lowering your BFR to the 250 level and increasing your FF to a level that will allow you to dialyze your 8 hours with the time exactly the same. That would be with a BFR of 250 ml/min a total of 120 liters of blood during an 8 hour session making 60 liters of total dialysis volume run at an FF of 50%
Your post makes complete sense. Why do you think America is so backwards on the dialysis issues?
I was on Short Daily NxStage for 16 months with a blood flow rate of 450! I used 20 liters of dialysate and my treatments were about 4 hours long. I learned about Nocturnal through IHD, so I was surprised when I switched over to Nocturnal and they wanted me to run at 400 BFR. I ran for about 2 months before having access issues, got an infection in the fistula, and had a chest catheter installed. Even the very experienced nurses have problems with my twisty, branchy, deep diving fistula. I successfully used the chest catheter at home for about 7 months before receiving a transplant on November 16, 2013.
I'd definitely talk to the dialysis team about this if I was still on dialysis. I was thrilled when my cycler left; unfortunately, I traded a known set of issues/time constraints for some serious side effects. :(
Sorry to hear about your NxStage experience. Your story is exactly why I stated that America is quite backwards in its approach to dialysis. The rest of the developed world knows you must run longer, slower and more frequently than the American experience. The US dialysis system is based on a business model, not a medical model of ideal care. That really explains why America is backwards. Here, they want short, infrequent sessions on and off the needle as quickly as possible to run as many patients through the machine.
Telling you to run at 450 is a result of how NxStage designed their machine based on the American model of short dialysis, as short as possible. Many patients are told to INCREASE blood pump speed above what they ran in-center. That defies the logic of preserving fistulas with lower pump speeds as especially practiced in Japan where 250 is a common speed for in-center patients as well.
Running at 400 ml/min for nocturnal shows a lack of understanding of how nocturnal works. It is completely based on TIME not Urea clearances. Middle molecule clearance as well as PO4 is TIME dependent. There is an element of volume of dialysate, but the most important factor even with low volumes of dialysate is TIME. That is why many patients on 20 liter of dialysate on NxStage need phosphorus supplements with nocturnal regimens that they didn't need with the same volume on short daily dialysis.
So that in simple terms is the major reasons I made the statements in the prior post.
I wish you well with your transplant. It is not worry free but it does offer many advantages.
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I did not know that there are now NxStage clinics! Where are they, and when did they open? What do you think made them decide to become for-profit dialysis providers? That's interesting and unnerving at the same time.
Why is it unnerving? NxStage is a for profit company that was leasing machines, not a charity. They are just offering more services using the same business model.
It's like the bumper sticker on trucks "cash, grass or ass .... no one rides for free".
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After reading and emailing Dr. Agar and talking to NxStage people and my own experiences, I came to the realization that NXStage really comes down to dialysate volume and time on machine. The whole flow fraction idea is ridiculous as it is irrelevant. I just set our default FF at maximum and dont even look at where we actually are in each treatment. What I do care about is time on machine, blood speed and dialysate volume. The dialysate speed only is important interms of final time on machine . The faster I run the dailysate speed the less time on machine and vice versa.
Where Nxstage has its advantage is in the extra number of days of treatment per week, and the flexibility of running it as fast or slow as I want. I keep the blood speed down to 340 now but still get 63 liters of blood cleared through by slowing down the dialysate and getting a longer treatment. We run about 3:08 now. Thats 15 hours and 40 minutes per week.
There is no reason to run the blood speed over 350.
Nxstage weakness is volumes over 30 liters up to 50. Since the saks are 50 or 60 , there are problems with wasting dialysate over 30 and under 50. WE run 30 liters and I would hesitate to run over 30 or less than 50 or 60. They need more flexibility. I would love to tgry 35 to 40 liters but it wouldnt be easy on this system.
I dont understand any one at home running a blood speed over 350. The centers do it for time expediency to get people out faster but at home we can run longer and slower. I do like Nxstage for the ability to do that. Short of nocturnal which I cant do easily , NxStage offers the most time on machine daily treatment offers.
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I did not know that there are now NxStage clinics! Where are they, and when did they open? What do you think made them decide to become for-profit dialysis providers? That's interesting and unnerving at the same time.
Why is it unnerving? NxStage is a for profit company that was leasing machines, not a charity. They are just offering more services using the same business model.
It's like the bumper sticker on trucks "cash, grass or ass .... no one rides for free".
Because dialysis shouldn't be based on a "business model" and should not be "for-profit'. The US dialysis industry is rotten from top to bottom. We all know that. Imagine some company telling you that you can have your life saving treatment only on certain days. They get cash for putting your ass under the grass. Do you really want your treatment following the philosophy you read off of a truck's bumper sticker? Good luck with that.
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Because dialysis shouldn't be based on a "business model" and should not be "for-profit'.
Do you really think the NxStage would have been designed and brought through FDA approval by a bunch of volunteers, or that investors would have fronted the large amount of cash required (think IPO) to bring a new machine to market absent an expectation of ROI?
The US dialysis industry is rotten from top to bottom.
No doubt true in any business where there is a conflict between "best treatment" and "profit maximization"
Do you really want your treatment following the philosophy you read off of a truck's bumper sticker? Good luck with that.
It is not about what one "wants", but the reality of economics. I would love it if centers would dialyze me fore free, but then, I would also love it if Exxon would fill my tank for free. Both are equally likely.
I don't know of any dialysis center where the doctors, nurses and techs work for free, or suppliers that give away their machines and supplies. Non-profits can be every bit as ruthless as for-profit centers when it comes to "no payment, no service", and the distinction between the two is largely meaningless to the patient who is told "you won't be treated here until you, your insurance company or medicare agrees to pay us."
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What is the benefit of the high flow NxStage machine over the existing one? When it comes to the physics of these machines, I find it hard to understand. When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine, and that I would be no advantage to me. I like to be armed with knowledge so that I can aim to get the best treatment.
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When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine,
You've indirectly hit on one of my concerns about switching to NxStage. I'm 103kg EDW and concerned that lower clearances of NxStage will be really low given that I am on the large size (given how many patients I saw weighing at 70kg or so at the clinic).
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I was 95kg EDW when I was on NxStage and had no problems with clearances.
When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine,
You've indirectly hit on one of my concerns about switching to NxStage. I'm 103kg EDW and concerned that lower clearances of NxStage will be really low given that I am on the large size (given how many patients I saw weighing at 70kg or so at the clinic).
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What is the benefit of the high flow NxStage machine over the existing one? When it comes to the physics of these machines, I find it hard to understand. When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine, and that I would be no advantage to me. I like to be armed with knowledge so that I can aim to get the best treatment.
The regular machine runs up to 12 liters dialysate per hour. The high flow runs up to 18 liters per hour. There is no advantage to small people to switch. The larger patients will benefit as they can run larger amounts of dialysate quicker. It simply allows faster dialysis. If you are doing well at current amounts and run under 4 hours (not nocturnal) then there is no reason to switch. I do not plan to switch my wife.
If you are large and say need 60 liters per treatment, then speeding up from 12 liters per hour which takes 5 hours to new faster machine at say, 15 liters per hour would cut the time to 4 hours. At 18 liters per hour it would be 3hours, and 20 minutes. So there is advantage for larger volume patients.
Dont forget that time on machine is most important. Going too,fast is not good either. I woudnt go less than 3 hours , 5 days per week.
NXstage is all about total volume of dialysate used. The larger the person, the more volume required. My wife is small and only needs 30 liters to get a URR of around 60% usually.
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When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine,
You've indirectly hit on one of my concerns about switching to NxStage. I'm 103kg EDW and concerned that lower clearances of NxStage will be really low given that I am on the large size (given how many patients I saw weighing at 70kg or so at the clinic).
You should be able to get good clearances at your weight . I dont have all your particulars but based on a very generic person with your weight you could run 50 to 60 liters per treatment . Again that is very generic, you may need less . I looked at it with very good clearances and high KV/t. You would benefit from the high flow system but could also use the regular system at slower rates. Your nurse or doctor can run your profile on the on line calculator and give you exact figures on dialysate volume, blood and dialysate speed, and time on machine.
The pure flow system has saks of 50 and 60 liters. You get ultra pure dialysate with this which is purer than standard dialysis. That is anothe radvantageas it leads to less inflammation and cell damage.
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You would benefit from the high flow system but could also use the regular system at slower rates.
If I decide to switch, I will push for the high flow system and contact NxStage if my clinic has problems getting one for me, as I will lose all negotiating ability once the sale is made.
I know that NxStage will get directly involved to make a sale. One of the patients at my clinic was not considered a great home hemo candidate (non-compliant, always late for treatments). He contacted NxStage directly and asked "how do I get one" - and NxStage pressured the clinic to get him on home hemo. Word is he was a very successful home hemo patient and went from non-compliant to totally compliant once spared the indignities of the center.
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What is the benefit of the high flow NxStage machine over the existing one? When it comes to the physics of these machines, I find it hard to understand. When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine, and that I would be no advantage to me. I like to be armed with knowledge so that I can aim to get the best treatment.
Well, let's talk about the physiology of dialysis so that understanding these issues is pretty simple. Dialysis is based on the principles of osmosis involving semi-permeable membranes and solutes. For instance, potassium in a solution of higher concentration on one side of the semipermeable membrane will pass potassium molecules through the membrane from higher to lower gradient and water molecules on the other side passes through to the high potassium side until both are equal.
In dialysis, the same concept applies to a wide number of molecules. That is why your dialysis "bath" or otherwise called dialysate has specific concentrations of potassium, magnesium, calcium, sodium, glucose and buffers which in the NxStage is lactate. Urea is not part of the "bath" so the blood will always have a higher concentration than the "bath."
As the rate of dialysate increases, the urea clearance goes up in a linear fashion until about 200 ml/min. After that, it begins to plateau or flatten out the curve as the efficiency of removing urea drops. However, at all rates of dialysate, the higher you go, the higher the urea clearance is. Going from 100 to 200 ml/min, the efficiency is essentially the same. NxStage calls this "100%" dialysate efficiency at this part of the curve. They marketed their system on the mantra that 1 liter of dialysate is 1 liter of clearance. What they are not telling you is how efficient the dialysate is from the patient perspective. In other words, even if you run at 100% efficiency, but with too low a volume, you will not get as much urea clearance running at a "less efficient" 600 ml/min as in-center by far. It is a NxStage marketing scheme not a clinical outcome scheme.
I placed an excellent graph of this from Wellbound on a post I wrote a while back for DSEN:
http://www.billpeckham.com/from_the_sharp_end_of_the/2009/01/nxstage-dialysate-flow-rates.html (http://www.billpeckham.com/from_the_sharp_end_of_the/2009/01/nxstage-dialysate-flow-rates.html)
So in short, I personally believe EVERYONE on NxStage should max out their therapy and I know of no one according to the power of this graph showing increasing benefit at each step in higher dialysate flow rates who would not benefit from the high flow NxStage System One upgrade. However, the LDO's love NxStage for giving us a substantially lower "standard of care" on low volume home treatments. Without NxStage, dialysate volumes and rates would have continued at the conventional in-center rates of 1.5 to 2.0 times blood flow rates. The question then becomes, what will the legacy of NxStage become? One where we gained, or one where we lost? Looking at it from the dialysate flow rate alone and efficiency of dialysis based on urea clearances per TIME on the machine, we have clearly lost and the LDO's will not budge in getting it back. You can calculate how much dialysate volume and flow rates you would have at in-center rates just by multiplying your Blood Flow Rate (BFR) by a factor of 1.5 to 2.0. Putting it in NxStage terms that would be an FF of 150% to 200%. Looking at an FF of 35% that is quite usual with NxStage shows the power of in-center dialysate flow rates compared to the standard flow rates of NxStage on the old System One.
That is the new battle before us. With about 10 years of literature supporting low flow dialysate systems and information from the FREEDOM studies, we will be sore pressed to ever see the new upgrade UNLESS it is to reduce the frequency of dialysis by the LDO's. In fact, that is exactly how NxStage marketed their new high flow capacities last April.
"This latest regulatory milestone reflects strong and systematic execution against our product pipeline," said Jeffrey Burbank, Chief Executive Officer, NxStage Medical, Inc. "With this new capability, NxStage therapy may be prescribed less frequently, for example 3 times per week or every other day, at treatment times consistent with those that patients and physicians experience in-center today. We're strong believers in longer and more frequent dialysis for the clinical benefits; still, high flow opens the NxStage solution more broadly to the patient segment that wants the benefits of home, but at in-center frequency."[/b]
http://ir.nxstage.com/releasedetail.cfm?ReleaseID=760385 (http://ir.nxstage.com/releasedetail.cfm?ReleaseID=760385)
This leaves NxStage speaking out of both sides of their mouth. On the old side is higher frequency is important, on this side, higher volume is important and more frequency is not. Where NxStage will stand in the future as dialysis "advocates" remains to be defined in the coming years.
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When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine,
You've indirectly hit on one of my concerns about switching to NxStage. I'm 103kg EDW and concerned that lower clearances of NxStage will be really low given that I am on the large size (given how many patients I saw weighing at 70kg or so at the clinic).
I weigh about 90 kg and run 40 liters for 4 hours at a time. I am hoping to increase my volume. Volume and TIME on the machine are the biggest issues if you are considering switching to NxStage. If you can run nocturnal at 60 liters, doing the math of BFR of 250 for 8 hours, that is a BLP of 120 liters. with an FF of 50%, you will easily run the 60 liters at 125 ml/min, easily within the capabilities of the old System One and find that your clearances rival in-center and your phosphorus might need some supplementation which I believe is best done by diet means. Why take a pill when you could have a pizza for instance or a glass of chocolate milk. Think about it.
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This leaves NxStage speaking out of both sides of their mouth. On the old side is higher frequency is important, on this side, higher volume is important and more frequency is not. Where NxStage will stand in the future as dialysis "advocates" remains to be defined in the coming years.
Excellent point.
:beer1;
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This leaves NxStage speaking out of both sides of their mouth. On the old side is higher frequency is important, on this side, higher volume is important and more frequency is not. Where NxStage will stand in the future as dialysis "advocates" remains to be defined in the coming years.
Assume the following:
1. Higher flow rates are an improvement for people who do near-daily NxStage
2. Higher flow rates are essential for persons doing NxStage on an 3x or EOD protocol
3. NxStage has a s--tload of low flow rate machines in use
4. NxStage generally rents, rather than sells, machines - so an upgrade for an existing user is a cost, not an extra sale.
Now, the problem for NxStage becomes how to promote the new machine without motivating everyone to upgrade.
Should NxStage:
1. Promote the new options made possible by the high flow machine
or
2. Do the above, but also remind patients that the new machine will result in "improved treatment" for persons already getting "adequate treatment"? (and, in doing so, initiate returns of their 12L machines, and assure that new patients will universally demand the 18L units, thus orphaning the inventory of 12L systems)
In days of old, a genius names Chet Osborne came out with one of the first personal computers - the Osborne One. It sold well, he was making a fortune, and all was well. His company then proceeded to announce a newer and improved model - before that product was ready for sale, and when there were still lots of Osborne One's in the distribution channel. That one mistake effectively killed his company.
I suspect the NxStage lack of emphasis on improvement for existing customers is to avoid what is commonly referred to cannibalism in business, and in cases of pre-announcement causing the cannibalism, is known as the "Osborne Effect".
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When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine,
You've indirectly hit on one of my concerns about switching to NxStage. I'm 103kg EDW and concerned that lower clearances of NxStage will be really low given that I am on the large size (given how many patients I saw weighing at 70kg or so at the clinic).
I weigh about 90 kg and run 40 liters for 4 hours at a time. I am hoping to increase my volume. Volume and TIME on the machine are the biggest issues if you are considering switching to NxStage. If you can run nocturnal at 60 liters, doing the math of BFR of 250 for 8 hours, that is a BLP of 120 liters. with an FF of 50%, you will easily run the 60 liters at 125 ml/min, easily within the capabilities of the old System One and find that your clearances rival in-center and your phosphorus might need some supplementation which I believe is best done by diet means. Why take a pill when you could have a pizza for instance or a glass of chocolate milk. Think about it.
You sort of made my point about the low flow machine being adaquate for many patients. Even at the maximum of 60 liters per treatment, the low flow machine can handle it if you spend anough time on the machine (5 hours for 60 liters at 12 liters per hour). Time on machine is one of the most important factor in dialysis . So the system can work .
Based on your size (90 kg) a generic patient like you would need 40 to 50 liters at 5 days per week. If you ran 50 liters at maximum 12 liters per hour, that would give a treatment time of slightly over 4 hours. 50 liters makes more sense as the sak holds 50 liters anyway. That would give you about 25% more dialysis volume. You could still use the low flow system .
I dont think NxStage is talking out of both sides of their mouths as much as dealing with reality. A lot of patients dont want to do more than 3 days per week of dialysis even though it is poor dialysis. So by offering this as an option they are opening up their system to more potential patients . Thats simply good business. They still stand by the option of more frequent dialysis as preferable.
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I dont think NxStage is talking out of both sides of their mouths as much as dealing with reality. A lot of patients dont want to do more than 3 days per week of dialysis even though it is poor dialysis. So by offering this as an option they are opening up their system to more potential patients . Thats simply good business. They still stand by the option of more frequent dialysis as preferable.
They are dodging the question: Does upgrading from a 12L to 18L and increasing flow for existing patients, who are receiving adequate dialysis, improve their treatment? If the answer is yes, the best thing for patients is an upgrade - but that may not be best for NxStage.
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I dont think NxStage is talking out of both sides of their mouths as much as dealing with reality. A lot of patients dont want to do more than 3 days per week of dialysis even though it is poor dialysis. So by offering this as an option they are opening up their system to more potential patients . Thats simply good business. They still stand by the option of more frequent dialysis as preferable.
They are dodging the question: Does upgrading from a 12L to 18L and increasing flow for existing patients, who are receiving adequate dialysis, improve their treatment? If the answer is yes, the best thing for patients is an upgrade - but that may not be best for NxStage.
You are stll missing the point. Its not the speed or flow rate that matters, its the VOLUME of dialysate. The high flow machine simply goes faster and is useful for patients who need higher volumes (60 liters) who want shorter dialysis. There is no advantage at all to others who are on lower volumes and need the speed at a slower rate to get enough time on machine.
Dr. Agar talks about the "waterfall effect" which in simple terms means more time on machine gets better clearance of the middle molecules. Going too fast with shorter times loses this effect. Time is critical , not speed.
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There is no advantage at all to others who are on lower volumes and need the speed at a slower rate to get enough time on machine.
Dr. Agar talks about the "waterfall effect" which in simple terms means more time on machine gets better clearance of the middle molecules. Going too fast with shorter times loses this effect. Time is critical , not speed.
Take the example of a patient who is getting nice long times. Does increasing the speed, without decreasing the time, offer any benefit to the patient?
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When I asked my nurse, she just said that they would only benefit bigger patients who require more time on the machine,
You've indirectly hit on one of my concerns about switching to NxStage. I'm 103kg EDW and concerned that lower clearances of NxStage will be really low given that I am on the large size (given how many patients I saw weighing at 70kg or so at the clinic).
I weigh about 90 kg and run 40 liters for 4 hours at a time. I am hoping to increase my volume. Volume and TIME on the machine are the biggest issues if you are considering switching to NxStage. If you can run nocturnal at 60 liters, doing the math of BFR of 250 for 8 hours, that is a BLP of 120 liters. with an FF of 50%, you will easily run the 60 liters at 125 ml/min, easily within the capabilities of the old System One and find that your clearances rival in-center and your phosphorus might need some supplementation which I believe is best done by diet means. Why take a pill when you could have a pizza for instance or a glass of chocolate milk. Think about it.
You sort of made my point about the low flow machine being adaquate for many patients. Even at the maximum of 60 liters per treatment, the low flow machine can handle it if you spend anough time on the machine (5 hours for 60 liters at 12 liters per hour). Time on machine is one of the most important factor in dialysis . So the system can work .
Based on your size (90 kg) a generic patient like you would need 40 to 50 liters at 5 days per week. If you ran 50 liters at maximum 12 liters per hour, that would give a treatment time of slightly over 4 hours. 50 liters makes more sense as the sak holds 50 liters anyway. That would give you about 25% more dialysis volume. You could still use the low flow system .
I dont think NxStage is talking out of both sides of their mouths as much as dealing with reality. A lot of patients dont want to do more than 3 days per week of dialysis even though it is poor dialysis. So by offering this as an option they are opening up their system to more potential patients . Thats simply good business. They still stand by the option of more frequent dialysis as preferable.
If you look at the future of artificial renal replacement options, all that I have spoken to in person involved in these endeavors is looking at weekly Kt/V's of 7-8 which is manifold higher levels than the defined "adequacy" of 2.0 weekly Kt/V that is the standard of care today. For anyone that understands these issues, then the issue of what is the optimal NxStage volume comes into view quite easily.
Where NxStage will venture is completely up in the air right now with their statement announcing the System One upgrade to high flow which was FDA approved last April. As noted previously, this is their statement:
This latest regulatory milestone reflects strong and systematic execution against our product pipeline," said Jeffrey Burbank, Chief Executive Officer, NxStage Medical, Inc. "With this new capability, NxStage therapy may be prescribed less frequently, for example 3 times per week or every other day, at treatment times consistent with those that patients and physicians experience in-center today. We're strong believers in longer and more frequent dialysis for the clinical benefits; still, high flow opens the NxStage solution more broadly to the patient segment that wants the benefits of home, but at in-center frequency."
How far NxStage takes the "at in-center frequency" is completely undefined at the moment. I know one very prominent nephrologist who will be addressing this issue in one of his 4 talks at the upcoming ADC next month. This would be a step back for a company that has cut it's teeth on the high frequency daily market standing as an "advocate" for dialysis patients. As I stated, it is an undefined marketing strategy the remains for the future to see where they will really stand on this ESPECIALLY once they begin to open more and more free standing dialysis centers. Will NxStage be the next Rubin dialysis, or will they be the next FMC or DaVita. It is for NxStage to define this themselves.
When looking at the Baxter machine already in use in Europe for home use, they provide in-center dialysate flow rates. In such, for myself, a 4 hour treatment at a blood flow rate of 350 ml/min would mean 525 ml/min dialysate using a factor of 1.5 for calculation. That would be 126 liters of dialysate for the Baxter VIVIA system. I believe that they are already directly targeting NxStage's low flow system by calling this new machine High Dose Dialysis. Bill Peckham dialyzed on the Aksys machine for I believe 2 years and states it is the best he has ever felt while on dialysis.
http://www.baxter.com/press_room/press_releases/2013/12_20_13_vivia.html
The advent of this machine obtaining the CE mark in Europe which is the counterpart of America's FDA is one reason why NxStage has responded with their "High Flow" NxStage System One upgrade. NxStage Announces FDA Clearance for New High Flow Capabilities with NxStage System One Yet, NxStage still falls far short of the VIVIA in dialysate clearances. Baxter also achieves much higher Endotoxin clearance than the American AAMI guidelines for standard in-center machines here in the US.
So should the message be that 30, 40 liters, 50 liters or 60 liters is "optimal." Absolutely not. That remains a competitive disadvantage for NxStage. It will be interesting how this plays out but for myself, NxStage is not gaining my favor with low flow dialysis. The very first thing I did when I started NxStage was to double the dose of my bags from 20 liter to 40 liters at my insistence over the objections of my nephrologist and the entire medical team. I feel justified that NxStage is doing exactly the same thing 4 years later with their "new" High Flow capacity.
http://www.billpeckham.com/from_the_sharp_end_of_the/2010/02/taking-nxstage-system-one-to-the-max.html
It is is mistake in their design that all the researchers looking into the new generations of renal replacement therapy disdain. In fact, one such researcher well know for his device stated to me flatly, NxStage is a lousy machine. Why, due to the low dialysate flow rates. They are quite puny compared to all other home dialysis machines in development and some already in the market place in other places around the world. I believe NxStage will have to do better than 60 liters total volume and 300 ml/min to compete in the new world of dialysis machines soon to come, well if the FDA ever gets around to approving any of them that is.
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There is no advantage at all to others who are on lower volumes and need the speed at a slower rate to get enough time on machine.
Dr. Agar talks about the "waterfall effect" which in simple terms means more time on machine gets better clearance of the middle molecules. Going too fast with shorter times loses this effect. Time is critical , not speed.
Take the example of a patient who is getting nice long times. Does increasing the speed, without decreasing the time, offer any benefit to the patient?
You must clarify which "speed" you are referring. Blood flow rates should be kept to a minimum with Japan finding 250 ml/min ideal even in-center. Dialysate flow rates are optimal at a ratio of 1.5 to 2.0 x the BFR. NxStage cannot approach that ratio even in the "High Flow" upgrade. BTW, Dr. Agar is NOT a fan of NxStage at all due to their low dialysate volumes and flow rates and is not advocating this machine for his patients in Australia.
The main focus of Dr. Agar's talk on the "waterfall of dialysis" is not about dialysate flow rates, but instead about avoiding high ultrafiltration rates that leads to collapse of the cardiovascular system by greatly exceeding the plasma refill rates.
http://www.homedialysis.org/news-and-research/blog/27-dialysis-waterfall-forget-urea
So in short, the optimal dialysis prescription is low BFR, dialysate flow rates 1.5 to 2.0 x BFR and enough TIME on dialysis to keep UF rates near the physiologic extracellular refill rates back into the cardiovascular system. Dr. Agar is planning further articles on these issues at the HDC site in the near future and John has an excellent ability to communicate these complex physiology issues in very simple terms that even accomplished researchers can appreciate. Add in Ultra-pure dialysate with the lowest endotoxin levels practically possible and those are the chief components of a single dialysis session that matters the most.
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That waterfall is not only rate-limited for fluid, it is rate limited for solutes, too, and different solutes move down that waterfall at different rates. Some zing down the gradients but others get stuck...like sticks on the rock face of a real waterfall...and take longer to be shaken loose.
THis is also part of the waterfall theory from John Agar. I beleive it is equally important, especially for patients that dont remove fluid during dialysis . Again it is time on machine , not speed to get to the middle molocules.
John talks about 3 compartments . The first is intra cellular, the second is extracellular, the third is blood.
Fluid and toxins(urea, middle molocules) all start in effect at the intracellular level where metabolisim occurs. Then via osmosis _diffusion etc. , they move across the cell membranes to the extra cellular space outside the cells but not in the blood. (interstitial). Then finally they diffuse into the blood. This all is rate limited and takes time.
Now as John talks about, we only can access the blood in dialysis . That is the furthest down the waterfall or third compartment. If we try to go too fast we clear out only the blood but dont get to the cellular level as that diffusuion takes TIME. Going too fast, we reduce the blood water levels too fast . Faster than they can be replenished by the diffusion from the cells to the interstitial to the blood. This can lead to collapse of the circulatory system. So again time is important.
If we go too fast we reuce the toxins in only the blood but not the cells.
Peter talks about dialysate speed at 1.5 to 2 times blood speed as "ideal". How do we know that. ? I would like to see studies proving this is true and not just accepted "fact" without soild proof scientifically. Is it possible that at those rates we are actually going too fast for some patients ,if not all. ? Is it possible that by going this fast we are removing molocules faster than we can diffuse them across the three compartments and thereby clearing blood mainly but not getting to the cells that effectively UNLESS WE RUN VERY LONG HOURS LIKE NOCTURNAL thereby giving enough time to finally diffuse the three compartments.
The basis of NXStage is by slowing the dialysate we go slower with the dialysate but due to the increased contact with the blood get more saturation of the dialysate giving proper clearance of the blood. BUT could there be another benefit????
By going slower with the dialysate we are giving the natural diffusion across the compartments more time to work effectively? In effect we are not just clearing the blood fast but slowely clearing all 3 compartments at a more natural physiological speed that is GENTLER to the body and patient.
My point is many patients immediatly feel better clinically on NxStage then traditional dialysis. I know of quite a few just here in my area where that has ocurred. The reason may come down to a slower gentler more physiologically compatible dialyisis that works WITH the three compartments not faster than difussion can occur.
I have seen far too many patients on standard dialysis that feel sick after each treatment. It is too fast and harsh. It is as simple as pulling from the blood too fast , before the diffusuion can occur across the compartments thus creating strong osmotic pulls that are way faster then the body is used to , and the sick feelings, cramps , nausea , headaches are all related to this.
My wife has NO water taken off ever yet even she felt awful on standard dialysis. It wasnt the water coming off too fast . I beleive it was the movement of ions and molocules TOO FAST across the 3 compartments . On Nxsatge she feels better each minute on dialysis and by the end is ready to exercise on the treadmill for 30 minutes. IT is the slow steady dialysis that allows this. It clearly is at a speed that the body can handle without stressing the natural physiology.
Now if you want to talk standard measuremets, however how crude , her URR runs around 60% so clearly we are doing the job compared with traditional faster dialysis.
I set her prescription up with a kt/v at 3.0 when I did the online calculater. That is higher then "required" by most clinics. She is getting good quality dialysis on 5 days of NxStage. In fact when I do any calculations on the online calculater on Nxstage I routinely use 3.0 as my kt/v. So far Nxstage has met that number with their prescription, so their theory is holding up. My wife is measuring out at over 3.0 when her blood work is done. (in her case it is at 30 liters dialysate only, so we have a lot of room to grow if needed).
Nxstage with the higher speeds coming out will be available to larger patients now. 60 liters can be done as fast as 3 hours 20 minutes at new maximum speed, and easily 4 hours for more time. I dont intend to switch to it as we are doing fine at our current speed of dialysate of 9.7 to 10 for 3 plus hour treatments. Clinically she is doing fine which as a doctor is my most important criteria. I see nothing to gain with faster treatments.
Something I have learned in 25 years of medicine practice, more is not always better. Sometimes less is far better. Too many people think if a little helps, more is better. This is generally not true. Sometimes it is actually far worse.
I may be proved wrong, but I do have a good understanding of physiology and the body . I beleive that we may be trying to go too fast with dialysis .; Not the time alone but the speed we actually try to clear molocules and of course water. WE may be causing untold trauma to the various organs and systems causing a cascade of changes and events that eventually damage the body. I know the Japanese run far slower then we do and perhaps their data will prove my point. but their dialysate speeds may be too fast.
I would like to see long term studies(over 10 years) when possible of NxStage and the slower dialysate principle. It may have been a marketing tool for them but THEY MAY HAVE INADVERTENTLY STUMBLED ON A CRITICAL IDEA THAT SLOWER DIALYSATE SPEEDS MAY IN FACT BE BENEFICIAL. We will see. So far I have at least seen this clinically in a few patients. They simply feel better.
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There is no advantage at all to others who are on lower volumes and need the speed at a slower rate to get enough time on machine.
Dr. Agar talks about the "waterfall effect" which in simple terms means more time on machine gets better clearance of the middle molecules. Going too fast with shorter times loses this effect. Time is critical , not speed.
Take the example of a patient who is getting nice long times. Does increasing the speed, without decreasing the time, offer any benefit to the patient?
That wont work on Nxstage. The whole point of the system is a set amount of volume . So with the same volume always if you increase the speed of the dialysate will automaticlly reduce the time. There is no way around that.
Again the prescription is based on your size, hematocrit, amount of fluid to be removed, and desiredkt/v/. I use 3.0 for our kt/v by the standards used in the US we are getting better then minumum dialysis. Whether that actually means anything, I dont know. BUT I will say that we are meeting that goal on our blood work . We are getting the 3.0 kt/v.
So the prescription works. We use 30 liters. slightly over 3 hours. (we run 9.7 per hour)
With your size you would require probably 50 liters as a guess. So at 50 liters you could run standard speed up to 12 per hour for time of slightly over 4 hours. Or you could go faster with shorter times on the high flow.
Try it and see how you feel with gentler dialysis. AS in my previous post yopu may find you feel better on slower gentler dialysis.
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Try it and see how you feel with gentler dialysis. AS in my previous post yopu may find you feel better on slower gentler dialysis.
I am pushing to get overnight which will give the benefits of long/slow no matter what the machine. The problem about "see if I feel better" is that I already feel great. Dialysis (6 months PD; one year hemo) has been a mega inconvenience, however, I have been feeling better than I ever expected to based on the storied I had heard from patients. And no, I don't have any residual left propping me up.
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this article hints at faster more agresssive dialysis causes issues with osmotic changes and hypo tension
Am J Nephrol. 2013;38(5):388-96. doi: 10.1159/000355958. Epub 2013 Oct 26.
Dialysis dose and intradialytic hypotension: results from the HEMO study.
McCausland FR, Brunelli SM, Waikar SS.
Author information
Abstract
BACKGROUND:
Intradialytic hypotension (IDH) is common and is associated with increased morbidity and mortality in chronic hemodialysis patients. A higher dialysis 'dose' may generate transient intradialytic osmotic gradients, predisposing to intracellular fluid shifts and resulting in hypotension.
STUDY DESIGN:
We performed a post hoc analysis of the HEMO study, a multicenter trial that randomized chronic hemodialysis patients to high versus standard Kt/V and higher versus lower membrane flux. In order to achieve dose targets, per protocol, adjustments were made in membrane efficiency, blood flow or dialysate flow before changing session length. Detailed hemodynamic and urea kinetic modeling data were abstracted from 1,825 individuals. The primary outcome was the occurrence of hypotensive events necessitating clinical intervention (saline infusion, lowering of ultrafiltration rate or reduced blood flow).
RESULTS:
Intradialytic hypotensive events occurred more frequently in the higher-Kt/V group (18.3 vs. 16.8%; p < 0.001). Participants randomized to higher-target Kt/V had a greater adjusted risk of IDH than those randomized to standard Kt/V [odds ratio (OR) 1.12; 95% confidence interval (CI) 1.01-1.25]. Higher vs. lower dialyzer mass transfer-area coefficient for urea and rate of urea removal were associated with greater adjusted odds of IDH (OR 1.15; 95% CI 1.04-1.27 and OR 1.05; 95% CI 1.04-1.06 per mg/dl/h, respectively).
CONCLUSIONS:
Higher dialysis dose, at relatively constrained treatment times, may associate with an increased risk of IDH. These findings support the possibility that rapidity of intradialytic reductions in plasma osmolality may play an important role in mediating hemodynamic instability during dialysis.
© 2013 S. Karger AG, Basel.
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That wont work on Nxstage. The whole point of the system is a set amount of volume . So with the same volume always if you increase the speed of the dialysate will automaticlly reduce the time. There is no way around that.
I have failed to properly formulate my question.
Assume I am prescribed X liters and run for 4 hours at 200ml/hour. Now, assume I have an 18L machine at my disposal. Is there any benefit to asking my doc to prescribe 1.5x liters at 300ml/hour to get more clearance in the same treatment time?
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Try it and see how you feel with gentler dialysis. AS in my previous post yopu may find you feel better on slower gentler dialysis.
I am pushing to get overnight which will give the benefits of long/slow no matter what the machine. The problem about "see if I feel better" is that I already feel great. Dialysis (6 months PD; one year hemo) has been a mega inconvenience, however, I have been feeling better than I ever expected to based on the storied I had heard from patients. And no, I don't have any residual left propping me up.
Overnight is definatly a better way to go if you can manage it. It is longer and slower. I hope you can pull it off.
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That wont work on Nxstage. The whole point of the system is a set amount of volume . So with the same volume always if you increase the speed of the dialysate will automaticlly reduce the time. There is no way around that.
I have failed to properly formulate my question.
Assume I am prescribed X liters and run for 4 hours at 200ml/hour. Now, assume I have an 18L machine at my disposal. Is there any benefit to asking my doc to prescribe 1.5x liters at 300ml/hour to get more clearance in the same treatment time?
Basic math. Same x volume at faster speed means shorter time on machine. You may get slightly quicker clearance but lose time which causes loss of the gain so it evens out . In the end it is still VOLUME . Read my articles on speed of dialysate. I beleive it is detrimental to go faster. Slower gentler is better
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Overnight is definatly a better way to go if you can manage it. It is longer and slower. I hope you can pull it off.
I have been told I can have overnight as soon as the local Fresenius clinic is able to offer remote monitoring for home hemo patients, or immediately if I can get a family member to agree to stay up all night to monitor me. I haven't have much luck with the later, but I have been assured that the monitoring is coming "soon".
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When you do go to nocturnal , rmember to slow down your blood flow to save your fistula. In Japan and Australia they run about 225 to 250 . Its gentler on the whole body and can save your heart and access.
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When you do go to nocturnal , rmember to slow down your blood flow to save your fistula. In Japan and Australia they run about 225 to 250 . Its gentler on the whole body and can save your heart and access.
My doc has already mentioned he will be doing that, along with moving me from a 15ga to a 16ga needle.
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Dear Obsidianom,
There are quite a few studies on solute diffusion rates. The end points of those are focussed on middle molecule clearances as well as PO4. The smaller molecules diffuse quite well. The middle molecules are most dependent on time on the machine and frequency, but they are also greatly influenced by highflux artificial kidneys and total dialysate volume. The main issue that Dr. Agar wished to communicate with his waterfall post is that volume, i.e., Ultrafiltration volumes and interdialytic fluid gains are the most important factors that kill patients. I was one of three people Dr. Agar asked to review and comment on his paper before he published it and that was the focus of our joint discussions.
So, the studies are relatively conclusive. In discussing NxStage with Dr. Agar, he is unimpressed with this machine for one reason, low dialysate flow rates. I am sure he would confirm that. If you look at my post in DSEN back in 2010, that was also the focus of my article stating to take NxStage to the max. That remains a significant detriment and reason why Australia has almost uniformly rejected NxStage. In addition, Dr. Agar points out that NxStage was designed on the failed American fast, violent dialysis session model of care that is also uniformly rejected in Australia and New Zealand. He much prefers the Baxter VIVIA system now with CE mark approval in Europe and pending FDA approval here.
So, as much as I appreciate what I have gained on NxStage the last 5 years, I cannot defend the low volume dialysate flow rates that is at the heart of their philosophy. In the end, the FREEDOM studies showing low dialysate volumes and flow rates may retard implementation of the better "HIGH DOSE" protocols with the new NxStage upgrade. I fear that people like me that desire to truly take NxStage "to the max" will never have that opportunity because NxStage has created a newer, lower "standard of care." In the end, should this occur, this will result in diminished benefits to patients. I have always believed that the NxStage low volume, low flow dialysate rates was a mistake. As you have noted, your wife felt terrible on the low volume NxStage and gained immediate benefit from increasing the dosage to 30 liters as you have documented in some posts here. That is proof in itself of the dangers of the NxStage philosophy of low volume dialysate. It is a failed paradigm that will be most difficult to rid from our system but that will be one issue that Dr. Agar will address directly next month at the ADC. Defending NxStage on this issue I believe is completely counterproductive in my opinion.
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Actually John just answered an unrelated thread at Home Dialysis Central on FB on exactly why he is not a fan of the NxStage System One and why he has rejected it for his patients in Geelong:
Now here's the next thing ... and I know some of you will have picked up that I am not fully convinced about the NxStage system. Why? Why has there been a reluctance in my part of the world (all the 'error' issues alluded to by Maz and Trevor aside) to accept this nice little portable machine? Well, the NxStage was designed (primarily) for US dialysis, for a home HD market that it (the NxStage) has almost on its own - and spectacularly - grown from nothing to a now creditable 1-1.5% of dialysis. Full marks and all credit to it that it has done so! But, it was designed principally to provide fast, hard (bad) but more frequent (good) dialysis, but in the home. To do this, but with a limited volume of bagged or batched dialysis fluid - ultra pure, as Peter rightly says .. a clear tick - it had to introduce a reversal of the standard dialysis practice of a high dialysis fluid and low blood flow ratio. It had to turn that long-standing dialysis dictum around and on its head, instead scripting a high blood flow to low dialysis fluid flow ratio - a reversal it named as the filtration fraction. In 'conventional single pass' dialysis (ie: Ian Chitty's Fresenius 4008B which, incidentally, we also use here in Geelong) - or any similar single pass system - the blood flow rate is commonly about half the dialysis fluid flow rate ... say, a Qb of 250 -300 ml/min paired with a Qd of 500-600 ml/ min. But, NxStage was (at least initially) limited to a 25-30 litre dialysis fluid batch. While it can do a bit better than that now with the PureFlow, it can still, at best, only offer a maximum dialysate volume per treatment of <60 litres. To compensate for this very low dialysis fluid volume and its associated low Qd, the counter-current pass of blood across the dialyser HAD to be ramped up! That meant reversing the Qb:Qd ratio so that Qb was 2-3 x greater than Qd ... the very opposite of conventional dialysis where Qb is only 1/2 the rate of Qd.
The problem, for us here in ANZ, is that we think this only serves to rob Peter (pun intended) to pay Paul!
To get anywhere near adequate clearance, the NxStage system and its blood/fluid flow dynamics required a very high Qb ... in turn demanding that the AVF be driven at flows that were anathema to us ... and, to be honest, they still are. We do not use high a high Qb. We think high Qb's are detrimental to good AVF care. Using the kind of Qb needed to compensate for the low flow dialysis fluid rates of the NxStage simply, to our view, introduces another 'bad' thing into the dialysis equation. Not only is a venous 'blast' back into the return vein of 350+ anathema to us, but to run a Qb of 350+, an arterial end 'suck' of the same amount is needed ... with the potential (and actual) result of structural damage to the AVF the arterial end too - at BOTH ends - venous and arterial. To be plain, we don't think that's a good trade, if you dont have to. And, in single pass systems, you dont have to!. But, turning down the pump speed on a NxStage to 300-ish (or, better, even lower - NB: our home patients on single pass systems run Qb's of 225 ml/min) would cause the filtration fraction physiology of NxStage to fail, and 'adequate' dialysis clearance would be unachievable.
So, for this, and other reasons, we have decided to stick with what we do ... at least until newer, portables appear that allow low Qb's yet provide for a high clearance by still allowing a high Qd. How might that happen. Well, sorbent regeneration of the dialysis fluid for reprocessing then re-passing the dialysis fluid around and around, would allow that ... but, we would have to be convinced of (a) safety and (b) that the sorbent would not be supersaturated such that breakthrough occurred. It's not a new concept ... some of the 'old hands' like Nancy,will recall the REDY system. Other options may also emerge, but that discussion is not for here or for now.
Meantime, we remain comfortable, here in ANZ, with providing good dialysis clearances yet at low pump speeds (low Qb's) ... and we are likely to continue to do so until something better is on offer. Dialysis is, in essence, a trade off - as no system is ideal - but we believe it best to recommend to our patients to trade what is, in truth, still difficult portability for better fistula care, optimal small and middle molecular clearance and, through longer dialysis, to ensure a low UFR that does not threaten myocardial stun and allows intra-dialytic trans-compartmental fluid equilibration. For the reasons that underpin this last point, see the HDC blog on the Dialysis Waterfall Part 1. I think that will be our collective view here, at least till something better comes along.
Dori is right, choice IS important, and while mobility DOES matter to many, it is important, too, to make sure that patients who choose mobility understand that by doing so, they may sacrifice other benefits.
Now ... I can just imagine a raft of posts coming back in response to this post ... "I have run at flow rates of 450 for decades and my AVF is fine - etc etc" ... and that may well be true, for some - but it is unlikely to be true for most or all.
Again, the weakest link in your life-sustaining dialysis is not the machine but your access. Access protection HAS to be a paramount priority. I try to live and deliver that priority.
John Agar:
Sent from my iPad
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To HemoDoc(Peter)
"Our facility-based conventional patients run Qb’s of 325 on a 3 x 4.5-5 hr schedule … and her 5 x 3 hr schedule should still drive better clearances than they get at an equivalent Qb!r)," ( From John Agar to me via email pertaining to my wife on NxStage)
"As regards the waterfall concept – it applies equally to fluid and solute (see Part = just up) – though with solutes, there are greater disparities as a result of the differences between small solute clearance (ie: urea) and middle molecular clearance (ie: PO4 as a surrogate" Quote to me from John Agar
Now I want to discuss why I disagree that NXstage is as flawed as you have posted. (I have great respect for your knowledge and experience and this is just a debate, not personnal. You have taught me a lot).
Nxstage is not perfect. I can think of many things I would do differently including more flexibility on the saks size and types. BUT, it is the best we have for home use in the US. I have practiced medicine for 25 years and deal with realities. I run my own practice and know the business side of US medicine all too well. I am currently in the midst of a medicare RAC audit that many docs who do durable medical products are facing for items we provided patients 3 years ago. It is a terrible waste of our time . The worst part is the company medicare hired to do the audit gets a percentage of any money they can take back from us. That is like giving police a commission for every ticket they write out as their pay. It creates a system that is ridiculous. BUT that is the US medical system we live in. So its the same for dialysis.
Nxstage is a public company that has stockholders it is responsible to. That means they come before patients. That is the way of free enterprise in the US. Now I wont debate whether thnis is good or bad , as that is a whole other topic. BUT it is the reality we are in. So whiile we may want to get "perfect " dialysis from them , we have to remember they deal with economic forces that are pulling on them all the time.
Nxstage provided a way for much easier more frequent dialysis in the US. The other system form Fresenius is more labor intensive for the patient at home. It isnt as easy to use and requires special electical and plumbing lines and more space.
The big advantage of NXstage is the frequency of treatment. I know it can be done fewer times , but most patients do 5 days per week or more. The other system is done 3.5 or 4 days per week. Now in regards to John Agar and the fluid waterfall, this is a big ADVANTAGE. Less water builds up between treatments and less has to be taken off allowing slower UFF which is what the whole theory is about. He points out that 5ml/hour times the weight in kg is the max. speed that is safe for UFF. For example a 100 kg person would be at a max of .5 liter per hour safely. That is easier to achieve with more frequent dialysis like on Nxstage.
Now John Agar doesnt like NxStage as much as their home system in Australia. But his reality is far different then the US. They do almost exclusively nocturnal , 6 to 8 hour dilaysis. That is not going to happen easily here in the US. It is a different mind set there. NxStage may not be better for them but in the US we dont do that kind of time on machine they do and so comparing NXstage to their home machines isnt a fair comparison in the US.
NxStage still offers more total time on machine then the other home system here unless the other is nocturnal. For day time use it is still superior time on Nxstage.
Now go back to my point about speed of dialysis. I still dont see any studies or even the ability to measure how fast diffusion FROM ONE COMPARTMENT TO ANOTHER takes place . I am not talking about diffusion across the dialsisis filter from the blood. I am talking about from the cells to the interstitial compartment and then from the interstitial to the blood where we finally access it in dialysis. That to my knowledge has not been or may not be measurable easily. Yes we clear the blood fast but what about the rate the molocules go from the cells to the intercell area and then to the blood. ? My best guess is that it is quite variable form patient to patient based on factors like proteins in the system and other molocules that vary greatly from patient to patient. As a surgeon I have seen how different exudate in the tissue is from patient too patient and how much this effects healing rates . Some patients have thick protien filled exudate while others are more watery and thin. This clearly will effect diffusion at the cellular level. So bottom line, we dont have proof that speed of dialysis clearance can be truly measred at the cell and intreacellular level, we just test the blood where we have access . This is just the final step in the line from compartment to compartment. We cant prove what speed is actually most efficasious as we cant measure the inner compartments . Going too fast may be detrimental to some patients. See my earlier post with the abstact article on that .
So bottom line, NxStage may in fact be more suitable for some or many patients as it is a slower dialysis . It may be less harsh on the body.
I did some checking on Nxstage with slower blood speeds as John Agar beleives we should do. I found at least for my wife I could run as slow as 250 blood speed and still get a Kt/v of 3.0 ( I realize this is an imperfect measure of dialysis but its all we have). It simply requires we run longer dialysis sessions ( long enough to get similar blood volume as at higher speeds) which is what John Agar prefers. So according to the on line calculator Nxstage can handle slow blood speeds . I plan to keep lowering ours over time and check this out .
Now I agree that the original dialysate volumes were too low. I increased ours from 20 to 30 as I have posted. But actually with the on line calculater now available , I can see where it appears they have upped the volumes form 2 years ago . I got to 30 liters by using THEIR online calculator . It gave me the prescription of 30 liters at 5 days. I also know my wifes numbers from her blood draws pre an post show she is getting what is predicted for numbers so the calculator seems to work. I do beleive you could benefit from going to 50 liters as you have stated. That is not Nxstages fault, but the people in your clinic who wont listen to you.
So , yes its an imperfect system, but so is everything in life . All we can do is continue to strive for better. I commend you for all your efforts .
Given where we are in the US TODAY, I still prefer NXstage to anything else currently available here. I am thankful they made home dialysis so easy for me to do for my wife, and how good she feels on it. :clap;
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I admire the tireless work that John Agar dies for kidney patients. However he mentions trade offs, and how patients need to consider portability against more clinical outcomes. At the end of the day though, he is an outsider looking him. He clearly understands and empathizes with patients more than the majority of nephrologists, but he is not living with the reality itself and we have to consider the reality of trade offs. The fact is that as patients we have to balance not only physical trade-offs but also the psychological aspects too. Having a huge machine that prevents travel is anathema to me. I have a thirteen year old son and have been on dialysis for most of his life, and all of his life for the time he remembers. To deny him the opportunity to enjoy simple pleasures of childhood is just not worth sacrificing. Maybe I have a fatalistic attitude, but I have been dealing with this for more than twenty years. I should have even dead twenty us years ago. I have had twenty plus years of bonus days. I know that it is unlikely that I will have a normal lifespan. I am at peace with that. In the meantime, I will continue to do the best I can for both my physical and psychological well
-being. When a better portable option comes along, I will definitely be interested. Until then I will stick with my NxStage, together with its shortcomings, but also the benefits that I personally desire.
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NxStage is indeed a reliable and easy to use machine. It is also the choice of machines I went with back in June of 2009 understanding also the limitations of their low flow capabilities.
They have also set a new "low flow" standard that now accepted by the LDO's will be VERY hard to overcome as they now have the upgraded machine. When Baxter and FMC with the PAK get into the market which will happen one of these days, who knows when, I was told by the ex-CEO of FMC that it would be FDA approved by January of last year.
I won't hold my breath in getting the full 60 liter machine in a 4 hour session any time soon if ever. It sets up a choice for me when the Baxter and FMC PAK come on line of dumping NxStage. They will have to try and compete with this standard flow machines which are now called "High Dose." The marketing of the Baxter machine tells the story that NxStage has reset the dialysate flow curve standard and not to our benefit.
In that, the nephrologist of America are pretty uniform of their disapproval of NxStage. We are simply caught in a market where it is big, hard to manage, huge RO system and expensive plumbing and electrical work with the Baby K, or the simple to use NxStage that allows NxStage to expand the market. I have been relatively silent about the deficiencies of NxStage in the last 5 years because it was the only real game in town. That is no longer true. However, I did set out the principles of what I needed NxStage to do back in my post in 2010. The volume is simple too low.
Interestingly, I had a conversation with Dennis Deneau, one of the inventors of the NxStage System One and a Vice President of the company, at the 2011 ADC in Phoenix where I spoke at the Saturday Home Dialysis Symposium. I bluntly told Dennis, give me a machine that can do 60 liters in 4 hours and I will be happy with NxStage. Their ultra-pure dialysate remains their biggest competitive factor. He told me, I don't believe we can do that, but you will be happy with our new machine coming out. I can't take credit for the new 60 liter capability, but I am sure I am not the only person that they had that request. For me to feel well, I need three days in a row of NxStage before I take my break. Two sessions leaves me a bit down as far as how I feel. That is on 40 liters. Their clearances are simply too low. For 4 hours of dialysis, I get a Kt/V of only 0.8 at best. That is a poor use of 4 hours as far as solute removal. If I can get above 1.0 in a single session, then I have taken NxStage to the max. Will I ever see that with the LDO's having studies such as the FREEDOM study showing them that 20 liters in 3 hours is all you need? I won't hold my breath.
As far as what your clearances are with short or long dialysis sessions, as I referred to you earlier in two pm's, using 30 liters of dialysate over 3 hours or 8 hours, the clearance will be exactly the same. Brent Miller of Washington Medical School in St Louis discussed that at the 2011 ADC as well.
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I admire the tireless work that John Agar dies for kidney patients. However he mentions trade offs, and how patients need to consider portability against more clinical outcomes. At the end of the day though, he is an outsider looking him. He clearly understands and empathizes with patients more than the majority of nephrologists, but he is not living with the reality itself and we have to consider the reality of trade offs. The fact is that as patients we have to balance not only physical trade-offs but also the psychological aspects too. Having a huge machine that prevents travel is anathema to me. I have a thirteen year old son and have been on dialysis for most of his life, and all of his life for the time he remembers. To deny him the opportunity to enjoy simple pleasures of childhood is just not worth sacrificing. Maybe I have a fatalistic attitude, but I have been dealing with this for more than twenty years. I should have even dead twenty us years ago. I have had twenty plus years of bonus days. I know that it is unlikely that I will have a normal lifespan. I am at peace with that. In the meantime, I will continue to do the best I can for both my physical and psychological well
-being. When a better portable option comes along, I will definitely be interested. Until then I will stick with my NxStage, together with its shortcomings, but also the benefits that I personally desire.
As a doctor I absolutely see your point. Medicine is an art not a pure science. What is best on paper isnt always whats best for an individual patient. I try to practice that way. For you and many others Nxstage is a better choice because of factors like portability like you stated, or in some cases patients in rural areas with limited water(like me) who need a system that uses less water, or in many cases patients who simply need the easiest machine to use , or prefer more days on then they get with other systems.
There are always trade offs in real life medicine. Some patients have to take less medicine than ideal due to cost , or wont take optimum doses of medications due to side effects that they wont live with. There is always the quality of life issue that doctors should never forget. The patients have to live with the medicine or in this case the machine, and their quality of life cannot be discounted even if the treatment is sacrificed to some extent.
I have an inter5esting story as patient in my case rather than as doctor. When I was diagnose with stage 2 plus rectal cancer in 2006 I was told by all my treating physicians that the standard treatment would be a total perineal resection which would leave me with a permanent colostomy. Now I am an athlete and have been since I was a kid. i work out 2 hours perday even now at age 60 plus. I couldnt see myself accepting a permanent bag on my abdomen.
I did my own research and found an alternative that was common in Europe (but not in the US) and that involved less invasive surgery after chemo and radiation shrunk the large tumor. I was told by several doctors I would be risking my life and one told me I would "die needlessly". I stuck to my choice and ran my own treatment and found a surgeon who would do the local resection to save my body integrity. It is now 8 years later and I am still here. I was recently checked out by that surgeon who proclaimed me cancer free.
The moral here is that quality of life matters . As a patient I chose to go with a lesser quality procedure and risk death as quality of life is critical to me. I made a trade off knowing the potential consequences (death). I beleive every patient should have their quality of life taken into account and allow them to make their choices accordingly.
For you and my wife, NxStage is the choice . Perhaps it isnt as "good" as standard dialysis , although I am not convinced of that. But it allows for a better quality of life for some. Un til something better comes along, I am sticking with it for my wife.
(If I had the colostomy I am not sure I could care for my wife now and so the choice I made effected her just as yours effects your child).
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NxStage is indeed a reliable and easy to use machine. It is also the choice of machines I went with back in June of 2009 understanding also the limitations of their low flow capabilities.
They have also set a new "low flow" standard that now accepted by the LDO's will be VERY hard to overcome as they now have the upgraded machine. When Baxter and FMC with the PAK get into the market which will happen one of these days, who knows when, I was told by the ex-CEO of FMC that it would be FDA approved by January of last year.
I won't hold my breath in getting the full 60 liter machine in a 4 hour session any time soon if ever. It sets up a choice for me when the Baxter and FMC PAK come on line of dumping NxStage. They will have to try and compete with this standard flow machines which are now called "High Dose." The marketing of the Baxter machine tells the story that NxStage has reset the dialysate flow curve standard and not to our benefit.
In that, the nephrologist of America are pretty uniform of their disapproval of NxStage. We are simply caught in a market where it is big, hard to manage, huge RO system and expensive plumbing and electrical work with the Baby K, or the simple to use NxStage that allows NxStage to expand the market. I have been relatively silent about the deficiencies of NxStage in the last 5 years because it was the only real game in town. That is no longer true. However, I did set out the principles of what I needed NxStage to do back in my post in 2010. The volume is simple too low.
Interestingly, I had a conversation with Dennis Deneau, one of the inventors of the NxStage System One and a Vice President of the company, at the 2011 ADC in Phoenix where I spoke at the Saturday Home Dialysis Symposium. I bluntly told Dennis, give me a machine that can do 60 liters in 4 hours and I will be happy with NxStage. Their ultra-pure dialysate remains their biggest competitive factor. He told me, I don't believe we can do that, but you will be happy with our new machine coming out. I can't take credit for the new 60 liter capability, but I am sure I am not the only person that they had that request. For me to feel well, I need three days in a row of NxStage before I take my break. Two sessions leaves me a bit down as far as how I feel. That is on 40 liters. Their clearances are simply too low. For 4 hours of dialysis, I get a Kt/V of only 0.8 at best. That is a poor use of 4 hours as far as solute removal. If I can get above 1.0 in a single session, then I have taken NxStage to the max. Will I ever see that with the LDO's having studies such as the FREEDOM study showing them that 20 liters in 3 hours is all you need? I won't hold my breath.
As far as what your clearances are with short or long dialysis sessions, as I referred to you earlier in two pm's, using 30 liters of dialysate over 3 hours or 8 hours, the clearance will be exactly the same. Brent Miller of Washington Medical School in St Louis discussed that at the 2011 ADC as well.
I dont see why you are having such a hard time going from 40 to 50 liters as you are dumping the extra anyway. That makes no sense. I ran some numbers on a generic patient your size and NxStage calls for 50 liters at 5 days for a Kv/t of 3.0 which decent. You are simply not geting enough volume . That is not Nxstages fault. That is the fault of your clinic. I think you might find you feel a whole lot better at 50 liters if you try it.
I hate going behind the backs of clinics but perhaps it is time for you. Why dont you try it for a week or 2 and see how you feel and get some labs done with it. Maybe that will convince them.
50 liters at the max. of 12 liters per hour is a 4 hour and about 10 minute treatment. So it will only add 10 minutes to your time.
I have read several studies on the advantages of ultra pure dialysate including less inflammation and less heart damage. So that does remain a big plus for Nxstage.
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Actually, NxStage is complicit since they have published quite a few studies in their FREEDOM series showing improved outcomes on 20 Liters. The LDO's are running with this now and as long as someone has a weekly Kt/V over 2.0, they say you don't need any more. Anyone trying to get the high flow NxStage is going to be hard pressed to provide medical justification for that to these for-profit dialysis providers. If nothing else, it will make a good opening post on my blog after not writing for about a year.
As far as my situation, it is all about control and shows the fact that they could care less about how I feel or how my outcome is long term. Pure evil really.
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Basic math. Same x volume at faster speed means shorter time on machine. You may get slightly quicker clearance but lose time which causes loss of the gain so it evens out .
We are still speaking on different wavelengths ;D Assume that my doctor prescribes a higher volume of dialysate since a higher flow rate allows me to use 1.5X liters of flow instead of X liters in a single treatment. Consider a non-nocturnal treatment, and that with the 12L machine, my doc were to prescribe a volume that runs 4 hours at a 200ml flow rate. Assume further that nocturnal is not possible, and that neither my doc or I consider a 6 hour treatment reasonable. Would I see an improvement with 1.5X the dialysate, running at 300ml, over the same time? We are NOT talking constant volume.
By the way - thanks to all who have replied, particularly hemodoc and obsidianom - this has been a fantastically informative thread.
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Basic math. Same x volume at faster speed means shorter time on machine. You may get slightly quicker clearance but lose time which causes loss of the gain so it evens out .
We are still speaking on different wavelengths ;D Assume that my doctor prescribes a higher volume of dialysate since a higher flow rate allows me to use 1.5X liters of flow instead of X liters in a single treatment. Consider a non-nocturnal treatment, and that with the 12L machine, my doc were to prescribe a volume that runs 4 hours at a 200ml flow rate. Assume further that nocturnal is not possible, and that neither my doc or I consider a 6 hour treatment reasonable. Would I see an improvement with 1.5X the dialysate, running at 300ml, over the same time? We are NOT talking constant volume.
By the way - thanks to all who have replied, particularly hemodoc and obsidianom - this has been a fantastically informative thread.
The short answer is yes, the higher you take NxStage on clearances, the better your solute clearance for you the patient. I first wrote about the NxStage clearances and WHY the standard NxStage dosage was not a correct philosophy back in January of 2009, a few months before I started on my own NxStage treatments in June of 2009.
http://www.billpeckham.com/from_the_sharp_end_of_the/2009/01/nxstage-dialysate-flow-rates.html
If you look at the pop out of the slide showing the dialysate flow graph, you will see visually that for every increase in dialysate flow rates along the entire curve, there is a corresponding improvement of clearances. I looked at the issue once again in a year later talking about taking the NxStage System One to the max.
http://www.billpeckham.com/from_the_sharp_end_of_the/2010/02/taking-nxstage-system-one-to-the-max.html
If you look at the graph in this post by Dr. John Daugirdas, you will see how single pool Kt/V measurements are correlated with frequency and the resultant weekly Kt/V. The goal of several devices known and some not known yet are to bring the weekly Kt/V to the 7-8 levels approximating 40 ml/min of renal function. One reason to set this level is that in children, if you don't get them to the 40 ml/min level, they won't grow. That is the level that Victor Gura is looking at with his latest version of the WAK. The prototype achieved 25 ml/min clearances.
So stating that a Kt/V of 3.0 is good doesn't give the whole story of where the innovative devices, many of which no one outside of the cloistered researchers have ever seen, and the direction that these researchers are heading and why they have this level of clearance as their goal. If that is what research states is the direction we should head, why wait 2, 3, 5 or 10 years until the FDA approves these devices in development today. If I can achieve a weekly Kt/V of 4-5 by taking NxStage to the max, why wouldn't I do that now with the technology available right now?
If we don't push the LDO's to raise the limits, we will be stuck in the mortality and morbidity that has given America a black eye when it comes to dialysis issues. There is a truth in dialysis that holds true in almost all situations that more is better when it comes to improved solute clearances and increasing TIME and frequency on dialysis.
So, the short answer is yes, it will improve your clearances and the long answer following explains in part why.
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Basic math. Same x volume at faster speed means shorter time on machine. You may get slightly quicker clearance but lose time which causes loss of the gain so it evens out .
We are still speaking on different wavelengths ;D Assume that my doctor prescribes a higher volume of dialysate since a higher flow rate allows me to use 1.5X liters of flow instead of X liters in a single treatment. Consider a non-nocturnal treatment, and that with the 12L machine, my doc were to prescribe a volume that runs 4 hours at a 200ml flow rate. Assume further that nocturnal is not possible, and that neither my doc or I consider a 6 hour treatment reasonable. Would I see an improvement with 1.5X the dialysate, running at 300ml, over the same time? We are NOT talking constant volume.
By the way - thanks to all who have replied, particularly hemodoc and obsidianom - this has been a fantastically informative thread.
First off , thanks to all who are reading this and the feedback. I enjoy adding what i can and drawing out from Peter some of his genius.
I have been ironically doing most of this while watching Nxstage work on my wife , while monitering her treatment. I marval at the engineering of dialysis machines .
Now to answer your question exactly, if you go to 300 ml per hour for the same time of 4 hours, you would get 72 liters of dialysate , which Nxstage cant do . It maxs out at 60 liters. At 200 ml per hour you get 48 liters total vloume. So in theory you gain more dialysate at a faster speed. ____----BUT what do you really gain?????
Well, if you look at Peters (Hemodoc) graph you see that with Nxstage you get 200 ml/per min clearance of urea at 200 ml/per minute dialysate rate or 1 to 1. Its a nice easy fit. What is interesting is at 300 ml/min dialysate rate , you only go to about 230 ml./min urea clearance . Not a big improvement. So by going up 50% in dailysate , you only gain about 15 % clearance. Not that much benefit really.
I agree with Peter that maxing out the 200 ml rate is still best. Running the standard machine at 12 liters per hour (200 ml /min) is most efficient. The high flow machine really is for larger people who need 60 liter treatments and dont want to go 5 hours . They can cut it to 3hour, 20 minutes at fastest.
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So by going up 50% in dailysate , you only gain about 15 % clearance. Not that much benefit really.
Excellent - this was the sort of answer I was looking for. But, I don't see why I shouldn't go for the 15% gain if I am ambe to negotiate for the bigger system ;D
The high flow machine really is for larger people who need 60 liter treatments and dont want to go 5 hours
What is the weight cutoff for "larger"?
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Basic math. Same x volume at faster speed means shorter time on machine. You may get slightly quicker clearance but lose time which causes loss of the gain so it evens out .
We are still speaking on different wavelengths ;D Assume that my doctor prescribes a higher volume of dialysate since a higher flow rate allows me to use 1.5X liters of flow instead of X liters in a single treatment. Consider a non-nocturnal treatment, and that with the 12L machine, my doc were to prescribe a volume that runs 4 hours at a 200ml flow rate. Assume further that nocturnal is not possible, and that neither my doc or I consider a 6 hour treatment reasonable. Would I see an improvement with 1.5X the dialysate, running at 300ml, over the same time? We are NOT talking constant volume.
By the way - thanks to all who have replied, particularly hemodoc and obsidianom - this has been a fantastically informative thread.
The short answer is yes, the higher you take NxStage on clearances, the better your solute clearance for you the patient. I first wrote about the NxStage clearances and WHY the standard NxStage dosage was not a correct philosophy back in January of 2009, a few months before I started on my own NxStage treatments in June of 2009.
http://www.billpeckham.com/from_the_sharp_end_of_the/2009/01/nxstage-dialysate-flow-rates.html
If you look at the pop out of the slide showing the dialysate flow graph, you will see visually that for every increase in dialysate flow rates along the entire curve, there is a corresponding improvement of clearances. I looked at the issue once again in a year later talking about taking the NxStage System One to the max.
http://www.billpeckham.com/from_the_sharp_end_of_the/2010/02/taking-nxstage-system-one-to-the-max.html
If you look at the graph in this post by Dr. John Daugirdas, you will see how single pool Kt/V measurements are correlated with frequency and the resultant weekly Kt/V. The goal of several devices known and some not known yet are to bring the weekly Kt/V to the 7-8 levels approximating 40 ml/min of renal function. One reason to set this level is that in children, if you don't get them to the 40 ml/min level, they won't grow. That is the level that Victor Gura is looking at with his latest version of the WAK. The prototype achieved 25 ml/min clearances.
So stating that a Kt/V of 3.0 is good doesn't give the whole story of where the innovative devices, many of which no one outside of the cloistered researchers have ever seen, and the direction that these researchers are heading and why they have this level of clearance as their goal. If that is what research states is the direction we should head, why wait 2, 3, 5 or 10 years until the FDA approves these devices in development today. If I can achieve a weekly Kt/V of 4-5 by taking NxStage to the max, why wouldn't I do that now with the technology available right now?
If we don't push the LDO's to raise the limits, we will be stuck in the mortality and morbidity that has given America a black eye when it comes to dialysis issues. There is a truth in dialysis that holds true in almost all situations that more is better when it comes to improved solute clearances and increasing TIME and frequency on dialysis.
So, the short answer is yes, it will improve your clearances and the long answer following explains in part why.
I agree with more is better with time and frquency. That makes sense as kidneys function full time and dialysis is very limited time. So more is clearly better. BUT------I am not at all sure about speed . (dialysate speed)
Lets look clinically since that is something we can all relate to. I am hearing over and over about patients switching to the slower dialysate Nxstage system and feeling a whle lot better clinically. Again going back to my own wife it has been night and and day. Now in some cases that could be frequency as it is done more days then other systems.
But at least in some cases like my wife, we dont remove any fluid due to residual kidney function. Going more days obviously makes UFF less stressful as less is removed daily. But if there is no UFF then we look only at solute clearances. Why does higher frequency (more days) dialysis lead to feeling better? Well the variable here is more time on machine done at slower speeds. We are getting the same kt/v but doing it slower and gentler.
My wife used to get awful headaches and feel quite ill after conventional in center dialysis. That is with NO UFF. The classic story I hear form hundreds of patients is they feel washed out and tired and often headaches after dialysis. Now on Nxstage none of that occurs for my wife (she feels energized after treatment) and for countless others. The main difference is the SPEED of dialysis or the urea cleance which runs under 200 ml/min on the graph. Conventional runs closer to 300 ml/min which is 50% faster.
Now to me as a clinician in thinking rather than a researcher , I would go with the slower gentler dialysis . Now reaearchers are working to get better systems as Peter has written. But remeber, research starts on models and then animals but cant measrure HOW IT FEELS clinically until it is tested on humans for years. Too many drugs have been developed by researchers with lab models and on animals that when used on humans either didnt work as well or caused significant, even lethal side effects later. Just because we can do something to the body doesnt mean it is in our best interest clinically.
Going back to basics. The body works on homeostasis. Basically it tries to even out or rebalance the system after any cahnges occur . this is especially true if we artificially change or perturb the system. We can effect change but the body will try to go back to its set point.
Now my point is we can clear the blood faster with conventional dialysis then with Nxstage . Say for example its 300 ml/min to 200 ml/min blood clearance. Now as the blood is cleared more of the solutes have to come from the inner 2 compartments (cell and interstitial) via osmosis /diffusion to fill the gap or vaccum that clearing the blood has caused. MY QUESTION STILL IS HOW FAST IS TOLERABLE TO THE BODY before we create side effects like cramps, headaches , fatigue and general ill feelings. As we perturb the nsystem and it tries to right itself to homeo stasis we can pay a price clinically in feeling ill. Example ; we can technically lower blood pressure by taking off a lot of fluid and dehydrating the patient. But they will feel lousy and then homeostasis comes into play and the body will try to right it by increasing our thirst and reabsorbing water and decreasing urine output. Eventually it will fail and blood pressure will evn out as it was before through homeostasis.
Going too fast with dialysis because we can doesnt mean we should. I still want to see long term studies (over 5 to 10 years ) on a slower dialysate model such as Nxstage.
The other issue is the kidney is a very complex organ that is not simply a filter as some seem to think. Yet we do dialysis with just 2 things going on. We filter the blood through a counter current filter system and we remove fluid via hydrostatic pressure. We use fixed dialysate chemisty that dosnt have flexibilty to regulate sodium or calcium well for example. There are articles out now questioning this and why we dont have more variable dialtsate with flexible sodium and calcium levels. So we are still very backward in our technology . This may be more important then simple solute clearance. WE also need to look at the other basic functions of the kidney and try to mimic them.
Without getting too esoteric, the kidney transports ions and solutes across the loop of Henle with very low differentials between the osmotic pressures on both sides. So there may be a lot of filtration of blood but at the osmotic levels it is slow and gentle. Perhaps there is a lesson there for us in looking at dialysis . Perhaps NxStage has bumped into something that we should be looking at . Slower dialysis may mimic more closely what really goes on at the basic levels of kidney physiology. Clinically they seem to have a product that creates a less harsh dialysis and people feel better on it. Isnt that some of what medicine is about? Remeber the motto "First do no harm".
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So by going up 50% in dailysate , you only gain about 15 % clearance. Not that much benefit really.
Excellent - this was the sort of answer I was looking for. But, I don't see why I shouldn't go for the 15% gain if I am ambe to negotiate for the bigger system ;D
The high flow machine really is for larger people who need 60 liter treatments and dont want to go 5 hours
What is the weight cutoff for "larger"?
There is no exact cut off. They use a calculator (it is on line for medical people to use) that takes into account weight, height, sex, age, hematocrit , and UFF needs. I ran a generic for you base only on weight and I beleive it came out to about 50 liters but again that is very generic without your particulars and also without your blood speed and other info. You could easily run 50 liters on the slower system at 12 liters per hour for 4 hours, 10 minutes.
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You could easily run 50 liters on the slower system at 12 liters per hour for 4 hours, 10 minutes.
Great info - thanks again.
This would put my treatments on par with what I do now with the BabyK, though I only do 4 days a week with that systems (Tues/Thurs/Sun 4 hours and Friday for 3 hours), so it appears that for me the option would be "daily" rather than "short daily". Given that, I wonder if there would be a benefit to NxStage 5 or 6 days a week as opposed to increasing the BabyK frequency. They don't make figuring this out easy.
But, the real issue is getting onto nocturnal with a slower blood flow.
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You could easily run 50 liters on the slower system at 12 liters per hour for 4 hours, 10 minutes.
Great info - thanks again.
This would put my treatments on par with what I do now with the BabyK, though I only do 4 days a week with that systems (Tues/Thurs/Sun 4 hours and Friday for 3 hours), so it appears that for me the option would be "daily" rather than "short daily". Given that, I wonder if there would be a benefit to NxStage 5 or 6 days a week as opposed to increasing the BabyK frequency. They don't make figuring this out easy.
But, the real issue is getting onto nocturnal with a slower blood flow.
The big advantage of adding days by going to 5 or 6 is less UF required per treatment and less water build up between treatments.
John Agar writes that safe speed UFF is below weight times 5ml/hour. So if you weigh 100 kg , the safest speed would be max. 500 ml /hour or .5 liters per hour. Above that speed begins to stun the heart and avove 10ml/hour times weight which in this case would be 1 liter per hour, CAN BE DEADLY. So if you have less water to take off per session it is easier to stay at a slower safer number. Personally I would go as slow as possible to reduce all the negative issues with faster speeds like cramps and headaches etc.
Obviously nocturnal would allow slower UF by its very nature anyway.
If you do daytime, Nxstage gives you more time on machine then your current time of 15 hours. You would get at least 21 hours at 5 days and 25 hours at 6 days which approaches nocturnal levels. Remember that time on machine is still the most critical factor . The whole waterfall effect takes TIME. In Australia where John Agar is they prefer at least 24 hours weekly.
So whatever you do try to add time. My wife is half your size and has a lot less muscle yet she gets the same number of hours you get now. That is why her kt/v weekly runs over 3.0. on Nxstage. Those 15 hours she gets clear her out as she only weighs 52kg. You weigh twice that almost and so your 15 hours arent going to do as much.
You also have more muscle(i hope) and that creates more urea and creatinine.
You could consider addding time on your current system if they will let you. Another day would be helpful. Remember kidneys run 7 days per week. Missing 3 days puts a lot of stress on the body.
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AND ON A FINAL NOTE -------GO PATRIOTS!!!!!! -- BEAT DENVER!!!
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So if you weigh 100 kg , the safest speed would be max. 500 ml /hour or .5 liters per hour.
More interesting data - please keep it coming.
I generally run in the 500ml to 600ml/hour range, much less on the days when I do two treatments without a day of in between.
I will ask my doc what he thinks about me adding another day to my current protocol.
Above that speed begins to stun the heart and avove 10ml/hour times weight which in this case would be 1 liter per hour, CAN BE DEADLY.
I ran at that sort of rate when I was new to D when I had an in-center appointment after the 2 day gap. Avoiding that gap was one of the motivators for going to home treatment.
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The issue of osmotic gradients during dialysis and the "possible" contribution to intradialytic hypotension is tempered by the reality that Sodium modeling used so widely in American dialysis units to prevent lowering of the osmolality by increasing sodium levels in the dialysate is one of the largest contributors paradoxically to intradialytic hypotension by aggravation of interdialytic weight gains from net sodium accumulation. This is one of the biggest contributors of left ventricular hypertrophy seen in dialysis patients.
Today, the best practice is to match sodium levels in the dialysate to plasma sodium levels in the patient. The discussion in the HEMO post hoc analysis on osmotic shifts causing hypotension is first of all speculative since post hoc analysis of different factors outside of the original study parameters are NOT randomized and controlled as other factors in the original study hypothesis. I did not spend $38.00 to get the full article, but they did not control for how the Kt/V in the high study group were manipulated through various interventions such as different artificial kidneys with variable membrane characteristics, variable blood flow rates, variable dialysate flow rates before changing session lengths.
It appears that you have extrapolated the results to dialysate flow rates alone which is really a stretch on this article since their High Kt/V group had multiple manipulations of several independent factors. In addition, the entire juxtaposition of Dr. Agar's article on the waterfall of dialysis is a treatise against the very practices utilized in HEMO study, a very unique American modality of dialysis that focuses on Kt/V which by the way is a dimensionless calculation only. What exactly does a ratio without dimensions really mean? Dr. Agar makes this point right from the beginning in the title of his article: The Dialysis Waterfall (Forget Urea: It’s Fluid That Kills)
Far too much emphasis has been placed on an arbitrary and flawed concept—Kt/Vurea—to the detriment of all else.
Kt/Vurea was developed over 30 years ago after the publication of the NCDS study following 165 patients over 24-48 weeks of 1970's low-flux hemodialysis. None were over 60 and none were diabetic ... not quite a "normal" dialysis population.
Worse, all focus was on one small molecule, urea, thought then to best represent a marker of good clearance. While we now know that it would be hard to find a less representative "toxin" (its trans-compartmental kinetics bear little or no relationship or similarity to the behavioral kinetics of any of Vanholder's vast list of uraemic toxins), Kt/Vurea is still used in the US as the marker of "adequacy." What bunkum!
We now better understand the importance of middle molecules like β2M, homocysteine, and the hydrophilic envelope around tiny phosphate that turns it into a time dependent trans-membrane traveller. Even then, this focus implies that dialysis is all about solute clearance. Another myth. Bunkum again!. . .
Most commonly it is fluid, not solute, that maims and kills the dialysis patient. It is fluid that stifles the breath, stretches the heart past the zenith of Starling's curve, and—when removed—is commonly removed so fast that the blood pressure and circulation collapses, coronary and myocardial perfusion falls, and the heart is stunned. That sequence is not solute-related. Tick that up to fluid!
In the dialysis setting, when fluid is discussed, it is all too often in tones of anger and confrontation. Dialysis staff regularly berate patients over excess fluid gain (the surrogate phrase for non-compliance) without considering why. After all, it is the patients' fault. More bunkum!
http://www.homedialysis.org/news-and-research/blog/27-dialysis-waterfall-forget-urea
The majority of articles on how to treat intradialytic hyptension are generated here in America BECAUSE of our short, violent dialysis sessions with high volumes of rapid fluid removal. That is indeed the point of Dr. Agar's article the specific target of his article is unique American style dialysis protocols not found elsewhere in the developed nations.
Looking at how the HEMO study developed the differing Kt/V groups, a study from DOPPS by Saran et, al in 2006 points out a major flaw of the HEMO study:
Longer treatment time and slower ultrafiltration in hemodialysis: Associations with reduced mortality in the DOPPS
In our study, the association of longer TTs and lower mortality was strongest in Japan, followed by Europe and the US (Figure 3). Although the explanation for this somewhat differential gradient in the relationship by region is not entirely clear, it may be due in part to the fact that in Japan, Kt/V targets are more often achieved by prolonging TT, whereas in Europe or the US, reliance on blood flow rates and dialyzer size to achieve Kt/V targets may be more common.
http://www.nature.com/ki/journal/v69/n7/full/5000186a.html
The DOPPS article goes on to show that treatment time (TT) is perhaps the largest determinant of the incidence of intradialytic hyptension (IHD). In the end, the post hoc analysis of the HEMO study on osmotic shifts leading to hypotension is an attempt to justify the American practice of sodium modeling in patients which is known today to increase the risk of cardiac injury. Matching the sodium to the plasma levels prevents this cycle of volume expansion during dialysis from high sodium loads leading to incredible thirst and huge weight gains between sessions. Once again, Dr. Agar dealt with this directly in his article above:
A Daily Scenario In Most Dialysis Units:
A patient arrives for dialysis with excess fluid to remove.
This is what tends to happen:
A (sometimes ugly) confrontation occurs with: "... you have not adhered to your fluid restriction ..."
With lots of fluid to remove, a high ultrafiltration rate (UFR) is required and set.
Surprise: the patient goes "flat" halfway through. Urgent "resuscitation" starts, with N saline (of course). But wait: isn't dialysis meant to be removing excess salt and water?
After loading up with salt and water, more fluid is taken off, and fast, for time is now short. Even if more flats are avoided, cramp is not and, at the end of dialysis, the patient is as limp as a potted plant at the end of a hot day ... and is grumpy ... and feels like death warmed up.
Before you is a patient with a maximally contracted circulating volume —to the point of circulatory collapse and hypotension. Before you is a patient with a maximally activated thirst mechanism. Thirst is an irresistible, primal, survival instinct buried deep in the brain stem. The patient is without a hope of suppressing it.
What, then, does the patient do? He/she drinks! So would you —you would have to! Your brain stem would insist on it! And so this "noncompliant" patient complies with the primal survival drive of thirst, and drinks!
In 2 days time (or 3, at the staff-convenient weekend), the patient returns, finally revitalized by fluid, but extra kilos "over". More angry berating ensues "You must be more compliant, you are killing yourself ..."
No ... we are the ones doing the killing.
Mind you, Dr. Agar DID NOT write this article for his colleagues in Australia or New Zealand. This is meant specifically for an American audience since this is a unique American treatment problem. So, if osmotic shifts have any part of IHD, not proven even after speculation of this issue for 30-40 years, it begs the question of why America ignores the most obvious cause, our short, fast and violent dialysis practices.
For the NxStage, even a max 300 ml/min dialysate flow rate is far below standard dialysate rates. Focussing on the Kt/V alone misses the essential message of Dr. Agar's treatise on fluid management in dialysis patients. It is an iatrogenic issue as Agar states above, No ... we are the ones doing the killing.
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So if you weigh 100 kg , the safest speed would be max. 500 ml /hour or .5 liters per hour.
More interesting data - please keep it coming.
I generally run in the 500ml to 600ml/hour range, much less on the days when I do two treatments without a day of in between.
I will ask my doc what he thinks about me adding another day to my current protocol.
Above that speed begins to stun the heart and avove 10ml/hour times weight which in this case would be 1 liter per hour, CAN BE DEADLY.
I ran at that sort of rate when I was new to D when I had an in-center appointment after the 2 day gap. Avoiding that gap was one of the motivators for going to home treatment.
The risk of more frequent dialysis is access issues. Unfortunately both frequency and total dwell time is associated with increased infections and other complications to the access. There appears to be many factors involved in this including integrity of the skin which is a barrier breached with each dialysis session. However, when looking at mortality and morbidity, despite potential increased access issues, mortality improves with each 30 minutes of additional dialysis as noted in the Saran article from DOPPS above. For those nephrologists who are enlightened on optimal dialysis issues, which is a minority of US nephs, the consensus appears to focus on 40 hours a week of dialysis as a reasonable target of the best you can do. Obviously, everyone must fit dialysis into their own personal goals outside of dialysis and other constraints, but for those who can accomplish this, they have the best outcomes.
Pauly et al in 2009 showed that nocturnal hemodialysis was equivalent in outcome with cadaveric transplant which opens up further discussion on the risk, benefits and alternatives for all renal replacement modalities in any given individual:
Survival among nocturnal home haemodialysis patients compared to kidney transplant recipients
Robert P. Pauly1, John S. Gill2, Caren L. Rose2, Reem A. Asad3, Anne Chery4, Andreas Pierratos5 and Christopher T. Chan3
+ Author Affiliations
Abstract
Background. Kidney transplantation is the gold standard renal replacement therapy. Nocturnal haemodialysis (NHD) is an intensive dialysis modality (6–8 h/session, 3–7 sessions/week) associated with a significant improvement of clinical and biochemical parameters compared to conventional dialysis. To date, no studies have compared survival in patients treated with NHD and kidney transplantation.
Methods. Using data from two regional NHD programmes and the USRDS from 1994 to 2006, we performed a matched cohort study comparing survival between NHD and deceased and living donor kidney transplantation (DTX and LTX) by randomly matching NHD patients to transplant recipients in a 1:3:3 ratio. The independent association of treatment modality with survival was determined using Cox multivariate regression.
Results. The total study population consisted of 177 NHD patients matched to 1062 DTX and LTX recipients (total 1239 patients) followed for a maximum of 12.4 years. During the follow-up period, the proportion of deaths among NHD, DTX and LTX patients was 14.7%, 14.3% and 8.5%, respectively (P = 0.006). We found no difference in the adjusted survival between NHD and DTX (HR 0.87, 95% CI 0.50–1.51; NHD reference group), while LTX survival was better (HR 0.51, 95% CI 0.28–0.91).
Conclusions. These results indicate that NHD and DTX survival is comparable, and suggest that this intensive dialysis modality may be a bridge to transplantation or even a suitable alternative in the absence of LTX in the current era of growing transplant waiting lists and organ shortage.
http://ndt.oxfordjournals.org/content/24/9/2915.abstract
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Thanks, Peter. Your input is much appreciated. Am learning a lot.
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Longer treatment time and slower ultrafiltration in hemodialysis: Associations with reduced mortality in the DOPPS
Peter, you and John both preach water is the killer as well as needing longer treatment times and slower UF. WELL NXSTAGE DOES ALLOW THIS. You may not like the dialysate speed but regardless it allows more frequent dialysis with more total time and consequently slower UF. Doing dialysis 5 days per week allows much less fluid removal and also slower speed of the removal.
If it really is water that kills then NxStage really is superior to the other home therapies as it is more frequent .Yes the dialysate is slower but since you guys both claim it is not urea that kills , but water then I stand by my point that Nxstage home therapy at 5 or 6 days per week solves the water issue nicely.
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"For the NxStage, even a max 300 ml/min dialysate flow rate is far below standard dialysate rates. Focussing on the Kt/V alone misses the essential message of Dr. Agar's treatise on fluid management in dialysis patients. " This is your quote from above.
The below is a quote from John Agar to me in an email.
"In contrast, we run our Qb at 225 ml/min = a much more sedate and AVF-friendly flow rate, I believe ...
Our standard single-pas Qd is 300 ml.min
This creates a Qd:Qb flow rate ratio of ~ 1.33."
NOW ISNT IT INTERESTING THAT HE RUNS DIALYSATE AT 300 ML/MIN AND NXSTAGE CAN NOW GO TO 300 ML/MIN. So why not run Nxstage at max dailysate of 300 and blood flow rate at 225 or so like they do in Australia? Nxstage IS capable of this. Again I point out that this system can work quite effectively even cpmpared with John's "perfect" rates in Australia. I realize we would need to max out the dialysate to near or at 60 liters to get enough time , but it is doable. At 18 liters per hour (300 ml/min) Nxstage would need to run at least 54 liters to get 3 hours per treatment. Thats not a bad number for many. 60 liters would take 3 hours and 20 minutes. At 5 days per week it would give a solid 16 hours and 40 minutes total.
So Nxstage can be run at eqivilant dialysate rates to what John uses in Australia. Nocturnal would be out but at least daytime would work well.
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Longer treatment time and slower ultrafiltration in hemodialysis: Associations with reduced mortality in the DOPPS
Peter, you and John both preach water is the killer as well as needing longer treatment times and slower UF. WELL NXSTAGE DOES ALLOW THIS. You may not like the dialysate speed but regardless it allows more frequent dialysis with more total time and consequently slower UF. Doing dialysis 5 days per week allows much less fluid removal and also slower speed of the removal.
If it really is water that kills then NxStage really is superior to the other home therapies as it is more frequent .Yes the dialysate is slower but since you guys both claim it is not urea that kills , but water then I stand by my point that Nxstage home therapy at 5 or 6 days per week solves the water issue nicely.
Dear Obsidianom,
Not sure what I would call here is preaching, hopefully I am basing my views not on my opinion alone, but well done studies over many years that are ignored for the most part by the American nephrology community.
You are right, urea in itself is not one of the more toxic components of the uremic condition. At least by our current understanding. Dr. Agar and the data that Dr. Agar bases this opinion is that Urea clears easily, but it is the more dangerous components of uremia such as high PO4, and middle molecules that mediate much of the damage of CKD along with p-cresol. The message is that measuring urea but ignoring the middle molecules and PO4 is the wrong emphasis. Now, solute clearances do matter so you must have the correct ratio's of blood flow to dialysate flow. NxStage reverses the usual 1.5-2.0 X BFR and so you must have high blood flow rates to get an "adequate" clearance. That is where the concept of "FF" came from instead of just setting a direct dialysate flow rate. Nevertheless, the ratios are just too low and very inefficient at the point of view of the patient.
Using Kt/V as a measure for comparison only, my 4+ hours on NxStage gains me less than 2/3rds the same clearance on a standard machine. I believe at 60 liters I could be about 90-95% of in-center clearances which coupled with the ultra-pure dialysate would be an advantage. However, the new portable machines, the FMC PAK and the Baxter VIVIA have near ultra-pure dialysate and much higher clearances. Where that plays out as best is probably yet to be determined, but in the minds of American nephrology folks, the higher Kt/V performances of these other machines, will make it hard for NxStage to compete in all likelihood.
So, no, it is not urea that kills to the best of our current knowledge.
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"For the NxStage, even a max 300 ml/min dialysate flow rate is far below standard dialysate rates. Focussing on the Kt/V alone misses the essential message of Dr. Agar's treatise on fluid management in dialysis patients. " This is your quote from above.
The below is a quote from John Agar to me in an email.
"In contrast, we run our Qb at 225 ml/min = a much more sedate and AVF-friendly flow rate, I believe ...
Our standard single-pas Qd is 300 ml.min
This creates a Qd:Qb flow rate ratio of ~ 1.33."
NOW ISNT IT INTERESTING THAT HE RUNS DIALYSATE AT 300 ML/MIN AND NXSTAGE CAN NOW GO TO 300 ML/MIN. So why not run Nxstage at max dailysate of 300 and blood flow rate at 225 or so like they do in Australia? Nxstage IS capable of this. Again I point out that this system can work quite effectively even cpmpared with John's "perfect" rates in Australia. I realize we would need to max out the dialysate to near or at 60 liters to get enough time , but it is doable. At 18 liters per hour (300 ml/min) Nxstage would need to run at least 54 liters to get 3 hours per treatment. Thats not a bad number for many. 60 liters would take 3 hours and 20 minutes. At 5 days per week it would give a solid 16 hours and 40 minutes total.
So Nxstage can be run at eqivilant dialysate rates to what John uses in Australia. Nocturnal would be out but at least daytime would work well.
I believe that is John's settings for his nocturnal patients obtaining about 40 hours of dialysis a week. And yes, NxStage can indeed produce that ratio for a short period of time. For nocturnal, you would have an FF of 50% to run 60 Liters of dialysate with a BFR of 250 ml/min for an 8 hour run. Given that PO4 and middle molecules are TIME dependent, a direct head to head comparison of middle molecule clearances is in order since many people on NxStage for nocturnal treatments need PO4 supplements. TIME is the most important factor in many ways, but that does not diminish the aspect of solute clearances especially at the short daily dialysis times of 2-3 hours used with the 20-30 liters dosage most NxStage people utilize today.
So, while urea is not the essential component of uremia and not the goal of dialytic therapies, solute clearances of the other molecules does remain an important aspect. The message John is putting across is a critique of the American reliance on urea kinetics as a measure of "good" dialysis when it is anything but that. You can crank up the blood flow rate, put a larger kidney on the machine and get very high Kt/V measurements in 3 hours of in-center dialysis, but the patient is dead in 3 years or less. That is what John is advocating against. This is a unique American problem in many ways.
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I think we are on the same wavelength here for the most part.
My defense of Nxstage is that of our CURRENT machines available it is the best we have I beleive.
When my wife was in center she felt horrible each treatment on the Fresenius machine. That is without fluid being taken off. WE were offered and actually pushed to the Fresenius machine to take home. It would have been a max. of 4 days per week.
Based on how my wife felt on Fresenius machine and the fewer days of dialysis and the ease of setup and use on Nxstage (and no special electric or water systems) we chose to go with Nxstage. I have never regretted our choice. She is doing so much better on Nxstage 5 days per week.
Now when newer systems come available in the future I will carefully look at them and also get your opinion . However who knows how long that will be. It could be years before we see that in the US as the FDA is slow at times.
By the way Fresenius just had over 100,000 dialysis machines recalled by the FDA. That is a lot of machines in the US alone.
Thank you for this enlightening discourse we have been involved in .
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What are the clearances for the dialyzer used by NxStage?
In particular, what is the NxStage dialyzer's Middle Molecule Performance (mL/min)?
I have never been able to get that info from NxStage. --One can easily find that information for Fresenius dialyzers:
http://www.fmcna-dialyzers.com/pdf/Optiflux%20Product%20Brochure%20Section/101046-01%20Optiflux%20High%20Flux.pdf
Have any of you measured your β2 microglobulin blood levels (mg/L)?
Reference range for non-ESRD is 1.0 -1.8
Inquiring minds would like to know.
8)
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I think we are on the same wavelength here for the most part.
My defense of Nxstage is that of our CURRENT machines available it is the best we have I beleive.
When my wife was in center she felt horrible each treatment on the Fresenius machine. That is without fluid being taken off. WE were offered and actually pushed to the Fresenius machine to take home. It would have been a max. of 4 days per week.
Based on how my wife felt on Fresenius machine and the fewer days of dialysis and the ease of setup and use on Nxstage (and no special electric or water systems) we chose to go with Nxstage. I have never regretted our choice. She is doing so much better on Nxstage 5 days per week.
Now when newer systems come available in the future I will carefully look at them and also get your opinion . However who knows how long that will be. It could be years before we see that in the US as the FDA is slow at times.
By the way Fresenius just had over 100,000 dialysis machines recalled by the FDA. That is a lot of machines in the US alone.
Thank you for this enlightening discourse we have been involved in .
The prior FMC CEO, Ben Lipps told me in January 2012, it would be out by the of that year. The VP for research told me later it should be by July 2013. You are right, who knows when it will come to pass. The FDA is quite slow in granting approvals even when items in use in Europe and Australia years ago still can't get approval here. Something just not right.
No matter what machine, the basic concepts will remain the same. Likewise, I am not holding my breath waiting for the American nephrologist to become enlightened any time soon either.
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Hemodial Int. 2014 Jan 19. doi: 10.1111/hdi.12125. [Epub ahead of print]
Which fluid space is affected by ultrafiltration during hemodiafiltration?
Tapolyai MB, Faludi M, Fülöp T, Dossabhoy NR, Szombathelyi A, Berta K.
Author information
Ultrafiltration (UF) is a common procedure performed during almost all dialysis sessions. During UF, several liters of fluid are removed; however, what proportion of this fluid is removed from which fluid space could not be clinically measured easily until now; we designed this study to evaluate the fluid spaces most affected by UF. This is a prospective cohort study of 40 prevalent chronic hemodialysis patients receiving thrice weekly hemodiafiltration (HDF). We measured the patients' fluid spaces using a whole-body bioimpedance apparatus to evaluate the changes of fluid spaces before and immediately after the HDF sessions. We recorded the data on fluid spaces, UF volume, and blood pressures. The cohort consisted of 40 prevalent HDF patients, aged 60.0 ± 5.2 years (37.5% men; 27.5% people with diabetes), and body weight 71.03 ± 15.48 kg. Achieved UF was 2.38 ± 0.98 L on HDF (measured fluid overload: 2.35 ± 1.44 L). The extracellular fluid (EC) volume decreased from 16.84 ± 3.52 to 14.89 ± 3.06 L (P < 0.0001) and intracellular fluid (IC) volume from 16.88 ± 4.40 to 16.55 ± 4.48 L (P = 0.45). Although urea volume of distribution remained effectively unchanged (31.38 ± 7.28 vs. 30.70 ± 7.32 L; P = 0.45), the degree of EC volume overload decreased from 13.60% ± 7.30% to 3.83% ± 8.32% (P < 0.0001). The mean arterial pressure also decreased from 122.95 ± 19.02 to 108.50 ± 13.91 mmHg (P < 0.0001). We conclude that source of net fluid loss by ultrafiltration is almost exclusively the EC fluid space. The intracellular fluid space is not significantly affected immediately after HDF.
© 2014 International Society for Hemodialysis.
This is a very interesting study. I go back to my posts of Jan 17/18 on this thread I write about osmosis rates from compartment to compartment. This study actually shows that with standard machines UF removes water initially only from the extracellular compartment. By doing that fast I beleive they are creating an osmotic gradient that must then shift to equilibrate. Perhaps this is why so many patients feel so awful when UF is done quickly. Also how about measuring the molocule changes from compartment to compartment. That would be interesting.
So again, with Nxstage dialyzing 5 days per week, less fluid is removed per treatment and can be done slower/gentler. This study at least indicates this is a better way to go . It also backs John Agars blog on waterfall concept of fluid removal. Too fast is deadly.
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Certainly, post dialysis fatigue (PDF) is a multifactorial issue as just about everything in dialysis. However, there is developing and confirmed evidence that recurring myocardial ischemia related to excessive ultrafiltration rates and collapse of the ECF, cardiovascular system with low perfusion of blood to the heart is the primary event causing PDF.
Association of segmental wall motion abnormalities occurring during hemodialysis with post-dialysis fatigue
Background Post-dialysis fatigue (PDF) is a common, debilitating symptom that remains poorly understood. Cardiac wall motion abnormalities (WMAs) may worsen during dialysis, but it is unknown whether WMA are associated with PDF.
Methods Forty patients were recruited from University of California San Francisco-affiliated dialysis units between January 2010 and February 2011. Participants underwent echocardiograms before and during the last hour of 79 dialysis sessions. Myocardial segments were graded 1–4 by a blinded reviewer, with four representing the worst WMA, and the segmental scores were summed for each echocardiogram. Patients completed questionnaires about their symptoms. Severe PDF (defined as lasting >2 h after dialysis) was analysed using a generalized linear model with candidate predictors including anemia, intradialytic hemodynamics and cardiac function.
Results Forty-four percent of patients with worsened WMA (n=9) had severe PDF, compared with 13% of patients with improved or unchanged WMA (P = 0.04). A one-point increase in the WMA score during dialysis was associated with a 10% higher RR of severe PDF [RR: 1.1, 95% CI (1.1, 1.2), P < 0.001]. After multivariable adjustment, every point increase in the WMA score was associated with a 2-fold higher risk of severe PDF [RR: 1.9, 95% CI (1.4, 2.6), P < 0.001]. History of depression was associated with severe PDF after adjustment for demographics and comorbidities [RR: 3.4, 95% CI (1.3, 9), P = 0.01], but anemia, hemodynamics and other parameters of cardiac function were not.
Conclusions Although cross-sectional, these results suggest that some patients may experience severe PDF as a symptom of cardiac ischemia occurring during dialysis.
http://ndt.oxfordjournals.org/content/early/2013/06/05/ndt.gft097.abstract
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Very interesting article. thank you.
I was actually taking off fluid today on my wife which is very rare. She seemed to drink a lot lately and overwhelmed her kidneys. I could here her all night breathing hard last night and she had trouble on the treadmill breathing. She had gained about .5 kg which is alot for a 52 kg woman. I followed John Agars fromula for UF speed . 52kg times 5ml/hour . That gave about 250 ml/hour UF speed. That was quite gentle on her . I took off .3 liters to be conservative as I can take off more tomorrow as we dialyze again tomorrow. That is one advantage to our Nxstage system .We dialyze more frequently and can be more gentle and conservative when taking off fluid as there is usually tomorrow.
The best part is she felt better after dialysis and was breathing better with no cramping or feeling washed out.
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The Fresenius 2008h/k/t series "recall" is because of the saline bag filling with dialysate during prime/setup if the drain line is clogged. It is not a "recall" per say but a Level II - notification to all users. I received the letter (http://www.nephrologynews.com/ext/resources/files/saline-bag--HHD.pdf) along with a form I was asked to sign and fax or return confirming I received the letter.