Citrate Dialysate?

Hello Dr. Agar,

I have recently come across Citrate Dialysate and they claim that it offers better clearances including for middle molecules. The thing that caught my eye however was the claim that you could reduce the requirement for heparin.

For someone like me who has been on dialysis for almost 15 years now, heparin has been a worry. I use about 10,000 units every night for my nocturnal sessions (of 7 hours). My skin has become very thin and gets cut easily.

What are your thoughts on this Citrate Dialysate? Is it good? Is it safe? Can you really avoid heparin during nocturnal dialysis if you use this dialysate?

Thanks!
Kamal



This is not going to be a straight-forward, from the hip, response as we have not used citrate dialysate (cost and availability being two of the key issues).

To answer this carefully and well, I will need to put a bit of time into the answer … something I will not have for a few days as I have only just flown in from the US after the ADC in San Antonio.

I will come back to this post over the next few days and update it when the back-log here has cleared.

I hope thats OK, Kamal.

Just check back now and then to see when I have got around to expanding the answer.

[U]See - now - below …[/I]

Dear Kamal

I have given a not dissimilar answer to this back on 6th Jan 2010 under the heading Heparin and GI haemorrhage where I discussed, briefly, the counter-options to heparin and where I touched on the use of citrate dialysate within the answer.

First, I have absolutely no experience with citrate dialysate. It is not widely available in Australia, while I think it is also more expensive than standard dialysate (I am checking on this latter issue) … but there would certainly be cost and registration implications if it were to be presented to our TGA, making its use less attractive.

Todd Ing has a quite special experience in and knowledge about citrated dialysate and Dori may wish to pass this question through to him for an addended answer. However, there is no doubt that it has been both investigated and used to minimize or negate the need for using systemic heparin to prevent clotting within the dialyser – as well as some evidence to support better tolerance of the dialysis treatment by selected patients as well as reports of improved clearance by some researchers.

It is important, when looking at the research papers on the use of citrate’ in dialysis, that care is taken to distinguish between the data on citrate used as an alternative to a heparin lock for dialysis IJ catheters … where there is a significant danger to calcium levels and to over-anticoagulation if inappropriately used or dosed … and citrate used as an alternative to acetate in the dialysate of bicarbonate dialysis – as well as, in the latter, the use and outcomes in RRT (renal replacement therapy) as they apply to acute kidney injury in ICU units (the various options in CRRT) and as they apply to chronic maintenance dialysis techniques.

Certainly, quite a bit of work suggests that citrated dialysate may have a number of potential advantages in the ICU setting for ICU-based CRRT techniques.

There is research data that reports better clearance of soltues, a better eKt/V, better middle molecular clearance (as evidenced by a fall in b2 microglobulin) and, yes, its use as an alternative to anticoagulation.

The data in maintenance dialysis, however, is not so clear cut. I am aware of only one case report (from Chris Chan – who, incidentally, used this very case as his discussion reference for a session on anticoagulation options in dialysis at the ACD in San Antonio last week) where citrisate (= citrated dialysate) was tried in NHHD – but not, it turns out successfully. There is a report of this case of Chris’s team (1st Author; Rose Faratro) … “The use of alternative anti-coagulation strategies for a nocturnal home hemodialysis patient with heparin-induced thrombocytopenia” … at:

http://findarticles.com/p/articles/mi_m5PMC/is_4_18/ai_n31203690/

To quote the citrate section directly from Rose’s paper (URL as above) …

[I]“On researching other forms of anticoagulation strategies, the HHD team, which includes the patient, opted to trial citrate dialysate (Citrasate). Although not available in Canada, as citrate dialysate has not as yet been approved by Health Canada, special consideration was given to our patient. The anticoagulant “citrate” is in the dialysate. The anticoagulant mechanism of citrate dialysate occurs when citrate enters the bloodstream and binds to ionized or free calcium, thus removing calcium from the blood-clotting cascade. This inhibits the blood from clotting, but may also, in theory, decrease the blood calcium level. The concentration of citrate in citrate dialysate used in this trial was 2.4 mEq/L. Unfortunately, the ability to measure the effects of citrate dialysate as an anticoagulant has not been developed.

The patient was trialed on citrate dialysate and did well on conventional dialysis, but it did not allow the patient to convert to nocturnal hemodialysis. Firstly, the patient was able to extend treatment time only to four-hour sessions. Secondly, the HDF could not be discontinued, as the blood circuit would clot regardless of citrate dialysate. However, the patient’s calcium levels were not significantly influenced by the citrate in the dialysate (see Table Three), and hemostasis at puncture sites remained at 30 minutes.” [/I]

So … to answer your question, we still don’t know.

My suspicion would be that:-

(a) you, like us, would have import and registration cost issues to start with

(b) even if available, then the cost implications for the longer, dialysis hours of nocturnal dialysis might prove a significant hurdle

© importantly, the anticoagulant effectiveness and the monitoring process for citrasate in NHHD, in particular, are unknown

(d) and as all this is outside my personal experience, a foil to this answer might be a ‘chip-in’ from Todd Ing who may entirely disagree with all I have said and say ‘he’s typing bunkum’ … or from Chris Chan, as the only person I am aware of who has actually tried it in an NHHD patient.

I am not sure if any of that helps … but at the end of the day, I don’t think I would be encouraging you to go down this track – isolated to a degree as you are there in India – before quite a body of work was done on the use of citrasate in maintenance day-based dialysis … then, if appropriate, the work were extended to its’ assessment in overnight dialysis.

Thanks Dr. Agar. That helped! I guess I will not use it for now.

Kamal