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Dialysate Temperature and Sodium Modeling/Profile


I have 1.5 years of hemodialysis experience as an RN. I worked in chronic setting for 9 months then went on two Acute setting in hemodialysis. I am currenlty in Acute setting at a large hospital in Atlanta area. I am still trying to learn when and when not use sodium profiling(linear,step, exponential) and when to increase or decrease dialysate temp during HD. Besides following the physician's order can somebody explain those two topics?

Chisca, RN

Specializes in Dialysis. Has 37 years experience.

1. Temperature. Cooling the dialysate causes vasoconstriction and an increase in BP. Our units policy is there must be an order for anything less than 36 degrees.

2. Sodium modeling. Water follows salt and if you increase the serum sodium it attracts water into the blood stream. We always end the modification 1 hour before the end of treatment. Linear/step/exponential is doctor preference. The effect on your pt will be as if you gave them a big bag of salty chips. They are going to get thirsty and more than likely have a drink. Or two.

Sodium modeling is also used in head injuries where neuro doctors want the pt to be hypernatremic to reduce swelling in the head. Those patients are usually too sick to stick their head under the faucet but if they could they would.

Wow, ok. Thank you very much for your input! So per the order and guidelines I would only use sodium modeling on a patient who is edematous? For example. Not use sodium modeling on somebody who for instance just has low bp, but has low bp and is edematous? I would lower the dialysate temp for somebody who needs bp support but not necessarily use sodium modeling? Would you be able to give me an example or two of when you would use sodium modeling or lower the dialysate temp? Per MD order of course.

Chisca, RN

Specializes in Dialysis. Has 37 years experience.

Only in the case of neuro patients do I consider sodium modification to have any value for the patient. Ask yourself what happens when the patient is off dialysis? The sodium is going to equilibrate and the patient you chilled for BP control is going to warm up. We have one nephrologist that likes to use sodium modeling for cramping. Sometimes it works. Mostly not. I will do both therapies if ordered but I have not seen any clinical benefit if it is only to support BP.

Where I am, sodium modeling has been discontinued and exact dialysate temperatures are not prescribed.

There is a temperature range, but we can use nursing judgement to adjust within the allowable range. Truth be told, using temperature to manage BP is not actually addressing the issue. It's like a cheat code. The underlying cause needs to be addressed--fluid volume, slow vascular refill, LVH or whatever the case.

As for sodium modeling, all it really does is make patients thirsty. When I was in chronics, there was a patient who insisted on going back to sodium modeling--because he believed it helped with his cramping. However, the cramping was caused by trying to remove too much fluid during a treatment and the excess fluid gains (usually over 5L between treatments) were caused by the patient being very thirsty after treatment and never being able to meet target weight. There was one instance that I've seen sodium modeling benefit a patient--a 93 year old who had stopped eating or drinking, missed several treatments and was uremic. Given fluid bolus before treatment with sodium modeling, the patient started drinking and gradually eating; they received daily treatment for about eight days straight. I really thought the patient was going to die and that the treatment prescription was futile...I was wrong.

There are ways to calculate the sodium and program a model that won't cause excess thirst--but it's not practical to do a custom model for every patient.

My two cents...sodium modeling is only appropriate in specific circumstances, not for the management of hypotension.