Hello,
Dialysis can not replace the natural function of a kidney; it can only approximate some of the functions. With the best current membranes utilized in the dialysis filters there is a sharp decline in the removal of molecules from about 1000 molecular weight (30 % of urea’s clearance) to 12,000 molecular weight (0 percent clearance). The kidney will maintain 100% clearance regardless of molecular size upto 30,000 molecular weight.
Its a fact of physics that the smaller molecules will be removed at a higher rate then the larger molecules and the longer you dialyze the greater the clearance of the larger molecules. The smallest molecules such as urea (60 molecular weight) will have much smaller quantities removed after 4 hours as the blood concentration has been substantially reduced ( urea reduction of 70% is about a kt/v of 1.4 ) and there is less to remove (dialysis clearance is exponential, not linear ).
Adequate dialysis , ie dialysis that restores a sensation of feeling well and being well, most likely is dependant on the clearance of molecules much larger than urea. This is why “more is better”.
Now what do you get comparing the urea clearance of dialysis with a kidney?
kt/v per session x sessions per week = KT/V per week
1.4 x 3 = 4.3
1.4 x 6 = 8.6
2.8 x 3 = 8.4
2.5 x 6 = 15
4.2 x 6 = 26
urea clearance of kidney in cc/min = KT/V per week
15 = 4.3
30 = 8.6
50 = 15
90 = 26
comparing a kt/v of 1.0 to 1.4 is like comparing a kidney clearance of 10 to 15 cc/ min. Not a whole lot better is it , when it would take a kt/v of 8.4 per session to equal a kidney clearance of 90 cc/min.
“adequate” dialysis with a kt/v of 1.4 x 3 per week is approximately having 15 cc/min of urea clearance in the kidney (but the kidney is also clearing the higher molecular weights at that rate and the dialysis is not). How many people felt well when their kidney function was down to 15 %?
dialysis for about 4 hours x 6 days per week gets you to 50% of normal urea clearance.
nocturnal dialysis for 9hrs x 6days per week gets you to 90% of normal urea clearance.
As the saying goes, individual mileage may vary, but if you want to begin to replace some of the clearance in the native kidney, more dialysis is needed and the current standard is woefully inadequate but financially feasible.
I mentioned this to my neph. yesterday as a matter of fact! I told him I don’t feel bad, but don’t feel good. When he asked what I meant I told him I felt about like I did 1 1/2 to 2 yrs before starting dialysis. I was still walking around but didn’t feel well. Of course not, my kidney function was declining. I liken it to the way one feels when recovering from a bout of the flu. The neph. agreed that although dialysis three days per week is good, it is not great and simply cannot replace the 24/7 function our kidneys once had.
I call this feeling “the electric door theory”. I used to be so perky I got to the electric doors before they opened; now they open, close and open again by the time I get there. The neph. and staff, and even other pts. remark that I have so much energy, and look so good, but alas they aren’t comparing me to what I used to be like, but rather are comparing me to all the other pts. in the unit, which are 70+ years old with multiple health problems. If you are a younger pt. in most dialysis units you are lost in the shuffle, with a clearance and hemoglobin that is adequate for a nursing home pt., but not a younger pt. who desires to be active and productive. Lin.
Hello,
It’s actually worse than I told. .When you started HD you likely still had about 5 to 10 cc/min of residual renal function. Eventually this is lost. Has anyone ever had their dialysis prescription increased from a kt/v of 1.4 to a kt/v of 2 or 2.4 per session as they lost their native renal funciton?
One point that I forgot to make earlier is that the “standard” we are comparing daily/nocturnal home hemo to–conventional, in-center, 3x week treatment-- has never been scientifically proven itself in the sort of double-blind, randomized study that some folks have been suggesting here.
Standard treatment is simply a historical artifact of the shortage of dialysis machines in the early '70s (one machine could be used for twice as many patients if each got treatment every other day). In the 80s when high flux membranes were introduced, allowing more efficient dialysis, instead of providing a better treatment in the same amount of time (then about 4-5 hours), times were cut to offer the same inefficient treatment faster!
When I started working in this field, ~1989, the standard for Kt/V was 0.8. The original DOQI guidelines for HD adequacy raised that somewhat, to 1.2–but didn’t really go much beyond the existing RPA guideline on that topic.
We’re looking at anecdotal evidence of how patients feel as being “soft” and “not scientific.” But we need to acknowledge that our measures of “adequacy” are mathmatical formulas based on unproven assumptions about how the body works. The “V” in Kt/V, for example, can never really be KNOWN, only estimated. And we know that urea is a stand-in for other molecules that may be far more important, but that we can’t measure…
IMHO, the purpose of dialysis is not to keep people merely existing, but to allow them to LIVE fully. Lin has posted very articulately about how her lab values are perfect–but she doesn’t feel well. How she, or any other individual, feels on dialysis is the true test of adequacy. It’s unfortunately not very scientific, and I truly hope that we find a way to quantify the difference between daily/nocturnal dialysis in a way that will be respected by scientists and clinicians, but in the meantime, it’s in the right direction and deserves our respect.
I want to be a Guinea Pig :lol: I trully want to have energy and be productive again. I struggle to keep weight off, exercise, keep the house clean ect… I’m ONLY 50 yrs. old and not lazy, just lethargic. If this is happening to me, there must be countless others that are struggling with the same feelings. If we’re willing to devote to taking care of ourselves we should be allowed to. I should think they would want more folks doing home hemo because that would mean we would free up chairs in the unit for the folks who aren’t able to do home hemo. Too, little staff is required for home pts… Lin.
Many opinions are offered, but the facts are the facts. How does the patient feel? Kt/v is meaningless if the patient is not well during tx and functions poorly outside dialysis. Long dialysis is certainly superior to the way dialysis has typcially been delivered in-center. But longer time is required to compensate for the lack of efficiency of a tx done correctly. If one patient can go from inefficient in-center txs, with all that goes with it ( i. e. fatigue, loss of stamina, loss of appetite, poor nutrition etc) and become completely restored to excellent health, with pink complexion as well, so can others. It is not the length of time that determines the quality of tx, rather it is the efficiency. A machine has not been invented yet that can do dialysis efficiently without any human expertise. But it is correct to say than an efficient machine is 95% the tx. It is the combination of an efficient machine and a throughly skilled tech that provides efficient dialysis, and we have experienced that an efficient tx can be achieved in 1/3 the time of long dialysis. Nevertheless, we respect any modality a patient chooses and we especially feel that a patient has the right to the machine of his choice.
Let’s me first address a pet peeve of mine. The proof is not in the pudding. The only way this saying makes any sense is when it is quoted correctly – The proof of the pudding is in the eating. In other words this saying maintains that there is no way to tell if some thing is good unless you actually try it and thereby gain first hand experience.
This is relevant to the discussion at hand because the only way any person would know if they are receiving short 3xWeek treatments equivalent to more frequent long slow treatments is by trying both and reporting on the differences and/or similarities. Just as the only way for someone to tell which pudding is better is by trying both. So ED until the person you are experimenting on eats the nocturnal and/or daily pudding you do not really know if your efficient dialysis is as good. Isn’t that correct?
IMHO what we need is to take people who are capable and want to do home hemo out of units and give them a chance on a home hemo program, same machines ect… and then do a study to see if these same people are doing better using a whole list of criteria, but the same criteria used to judge how well an incenter pt. is doing. As a pt. who feels ok incenter, but not that great, I would like people to not just look at me and my labs, but to aske me “so, how do you really feel”. It’s not the machines because I believe the machines are all capable of delivering a good tx… It’s the set up and time limitations in the unit that matter. Obviously because the same machines are used for slow nocturnal and home hemo as are used in the unit. I’ve been on the Althin (Braun), FMC h and now k, and still don’t feel any better. I look great, my labs are wonderfull, and the only health problem I have is the pkd. I have no fluid removal, am on no meds except for epo and Hectoral via tx… I’m 50 yoa and have no energy, and never trully feel well. Finally this week my new neph. said to me that three times a week txs. are not optimal, just ok as they do not even come close to the 24/7 toxin removal that normal functioning kidneys do. Lin.
I agree that everyone is different, and not everyone requires the same amount of dialysis. For me personally, nocturnal has been the best thing thats happened to me, as far as dialysis goes. I didnt even know about it until I was almost ready to go home on HD. Just looking at my blood results is proof of how good it is. And my hospital admissions have been alot less!
When I was on PD I basically spent alot of time with my head in a bucket. After about 12 months it got so bad I was not eating or drinking anything at all. I was admitted at least 6 times for this until I was put on HD after practically begging for a permacath. The thing that annoyed me was, I would be admitted with dehydration, they would give me IV fluids, made me feel a bit better, and was sent home. I would then get sick again, and be admitted again for the same thing. One doctor even said it was a “social” problem!! :roll:
Anyway, I was then put on HD (5hr 3-4 times per week), which helped a bit, but took a while for me to stop having the nausea and vomiting. What really helped was having the transplant removed. After that op and being on home HD for 4 months I was feeling a hell of a lot better, with minimal nausea.
Then started nocturnal, and after a month or so I started to feel even more better. I do have more energy, but its not constant, it is different for me every day. It is now coming into 6 months that Ive been on nocturnal and my energy is still improving. I am now able to do things I couldnt do before, like gardening, cooking alot more, housework etc. I am also able to do a bit of excercise on my good days.
I really am soo much better than before. I have also got my sex drive back from having none whatsoever, so it has to be good! hahahaha