Preventing Extracorporeal Clotting in the Acute Setting

Chisca, RN · Oct 6, 2013

You've got the saline flush angle covered, if you know beforehand the patient has a history of clotting you could suggest a citrasate solution to the nephrologist. Citrasate in the acid bath prevents calcium from being used in the clotting cascade and it is quickly metabolized by the body so it doesn't lead to systemic anticoagulation. Our unit stocks citrasate solution in 2K and 3K baths and we use it mostly with CRRT because of the slow blood flows and longer treatment times. Everyone's blood will clot sooner or later because when blood comes into contact with a foreign body (plastic in the tubing) it initiates

clotting, some patients are just more sensitive than others.

westieluv · Oct 7, 2013

Thanks for your reply. I have never heard of any of our nephrologists ordering citrasate in a patient's bath, and I know that we don't stock it. I wish we did, it sounds like a great idea that would prevent a lot of headaches.

Guttercat, ASN, RN · Oct 10, 2013

I am getting pretty comfortable in the acute HD setting, but I still worry about clotting the dialyzer during each tx. It has only happened to me on a handful of occasions, and my more experienced co-workers assure me that it happens to them too, that sometimes it just can't be prevented, but do any of you have any tips that would help to prevent it from occurring? I know how to increase my UF goal and then flush with NS liberally to compensate and prevent clotting, but sometimes I don't like to do that, especially if the pt is trending very hypotensive during the tx. We don't use heparin in our acute setting, so what else can I do to make sure that extracorporeal clotting, and the subsequent restringing of the machine, is less likely to happen?

It's a delicate dance sometimes, as you are experiencing.

A question, though. Why is heparin not used at all in your inpatient program? Fear of HIT? Fear of bleeds? Of course, many patients in an acute setting have medically complex issues and/or are unknown entities (ARF or newly-minted ESRD). But, still, I am questioning the rationale behind this broad, overarching policy of "no heparin."

As a side note, I've only had (annecdotally speaking) moderate success with Citrasate. I don't know if the "success" is coincidental, or is a direct result of its use.

Chisca, RN · Oct 11, 2013

A question, though. Why is heparin not used at all in your inpatient program? Fear of HIT?

My current medical director is adamantly opposed to heparin because of HIT. The environment I work in is a teaching hospital and he is instructing the fellows and residents not to use it. We still have private practice docs who don't have a problem ordering it so I'm not sure if this a temporary fad or the result of some new research.

Guttercat, ASN, RN · Oct 12, 2013

My current medical director is adamantly opposed to heparin because of HIT. The environment I work in is a teaching hospital and he is instructing the fellows and residents not to use it. We still have private practice docs who don't have a problem ordering it so I'm not sure if this a temporary fad or the result of some new research.

Yeah. I've seen docs jump on the latest ( scientific study-du-jour) bandwagon, only to jump off again a few months later. That said, if they are liable for unforeseen HIT incidences (however rare they may be in actuality), I can understand their conundrum.I really should google the latest research...One of the docs I worked with developed a "no heparin" habit for all ARF's/new-onset ESRD patients coming through the hospital doors. Made some treatments a nightmare. I think they wait for what the inpatient dialysis nurse reports back, and consider heparin initiation from there. That takes some of the potential legal heat off their backs.

ausrnurse · Oct 12, 2013

I don't really like saline flushes either - you're just giving the pt extra volume that you then need to get rid of, and one of the very experienced nurses I have worked with feels that it doesn't really prevent clots, it just lets you see that they are forming.

Honestly, if you're not using heparin, I think you just need to be able to recognise when you are going to lose your circuit and get the patient off before you lose their blood as well. I keep a close eye on my venous pressures and TMP and when they start to rise, I start getting ready to run back.

Chisca, RN · Oct 12, 2013

I keep a close eye on my venous pressures and TMP and when they start to rise, I start getting ready to run back.

And many times it is just in the venous chamber. I've tried to think of ways to avoid this, cardiac stents are coated with tacrolimus to prevent clotting but this would be expensive to do for a dialysis circuit. The venous chamber is enclosed to allow a blood sensor to determine flow, what if this could also emit a small, low frequency vibration that would keep the platelets from aggregating? Another idea would be some way to electrostatically charge the surface of the tubing to repell clotting? This is done in metal painting to get paint to adhere better to a surface so maybe the charge could be reversed? The things you think of during a four hour treatment at 2 o'clock in the morning. :)

NurseRies, BSN, RN · Oct 12, 2013

Thanks for your reply. I have never heard of any of our nephrologists ordering citrasate in a patient's bath and I know that we don't stock it. I wish we did, it sounds like a great idea that would prevent a lot of headaches.[/quote']
A couple things to watch for are to prevent total clotting of the system by monitoring your chambers, venous pressure, and TMP. If the TMP started at 40, and is now down to 10, but hovering between 10 and 0, return the blood and restring. Also if the TMP is positive, return blood immediately! Sometimes we can't prevent clotting, but we can prevent blood loss. Other nurses tease me occasionally bc they want to hold out as long as possible (maybe due to laziness or just don't want to change the system), but if the TMP is positive, chambers are dark, and I have an hour or more left, I am switching that system.
A very experienced dialysis nurse told me to tilt the dialyzer slightly so that it is diagonal, in hopes that any clots or small air bubbles that may cause clots will float to the sides instead of making it to the venous chamber. I don't really believe in the flushing theory, I mean it doesn't usually hurt to try, unless your patient needs fluid off desperately and had a low BP, in which case, I withhold the flushes.
One other prevention trick is to not have the blood pump stop if at all possible. If you keep flushing a catheter, adjusting a needle, or reversing the lines, the treatment gets paused and clots form when the blood pump stops. If your machine is constantly alarming, that person is way more likely to clot the system. My doctors don't give heparin very often either, so for me I try to prevent the loss of blood, and switch out the system before a total loss.

westieluv · Oct 13, 2013

The main thing that I am getting from this thread, which actually helps me immensely, is that this happens to the best of dialysis nurses and fairly often. I have had the impression that having to restring the machine is a personal failure and that I should/could have done something to prevent it. I'm now getting the impression that it isn't me, it is simply the process of hours of HD without heparin. Whew!

The thing that shakes my confidence is when a patient or their family member says, "Well, that's funny, XYZ Nurse never seems to have a problem when they do it." That makes me feel absolutely incompetent, even though XYZ Nurse assures me that this does, indeed, happen to her.

So much to learn, so much confidence to gain! :unsure:

Guttercat, ASN, RN · Oct 13, 2013

I've been able to head a complete or partial system clot-off at the pass many times ( via noting TMP/VP changes), but, other times (especially patients prone to clotting) you have either seconds or no seconds to react.

It's always good, especially on unknown entities (new/acute), to have all the supplies and the know-how to change out the venous tubing in a hurry. Saves on fluid return and blood loss. Especially if you can catch it before the dialyzer goes.

Chisca, RN · Oct 13, 2013

One of the first problems Dr Georg Haas faced in 1924 was how to prevent blood from clotting when removed from the body. His technique involved removing 400cc of blood, cleaning and then returning it to the patient. He used leeches to obtain hirudin to act as a anticoagulant. His first treatment only lasted 15 minutes. Not sure if it was due to clotting. He is credited with having performed the first dialysis treatment on a human but none of his patients survived longer than 6 days.