CRRT, TPN and Phos

[VCU07]

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For this of you who manage critical care pts, what's the most phos you have put in a TPN for a CRRT pt? Got a level <0.5 with 60mmole naphos in tpn and that's after an additional 45mmole bolus. Thanks

 

[njac]

For this of you who manage critical care pts, what's the most phos you have put in a TPN for a CRRT pt? Got a level <0.5 with 60mmole naphos in tpn and that's after an additional 45mmole bolus. Thanks

Wayyyy back in residency I had an HD or on TPN whose phos we couldn't get over 0.7.

We ended up pouring fleets phosphosoda in the HD bath.

CRRT though. Does the patient have any functioning enteral access?

 

[VCU07]

Unfortunately, no enteral access. It always freaks me out to use extremely high doses of electrolytes in parenteral nutrition. May need consider phos in the crrt fluids. Thanks

 

[njac]

Any chance you can get Q12H chemistries and maybe run a separate "electrolyte bag" so you wouldn't have to waste an entire TPN when they turn around?

Phos is a tough one, for multiple reasons.

 

[VCU07]

I thought about an electrolyte bag too. I don't see this pt. Coming off crrt any time soon. In fact, she continues to deteriorate. I'm trying not to give out too much info for privacy regulation. Got q12 chemestries and a prn phos in place.

 

[Eugenia]

I always thought HD does NOT remove phos unlike CVVH which does remove phos.
Can somebody comment on that?

 

[PharmDstudent]

How are the na and k levels looking? What about increasing phos by adding and then adjusting kphos in addition to having naphos? What about chloride levels? Can you ditch kcl for kphos or more naphos for nacl? Does she have calcium and an acetate in the TPN? (Remember that Phoslo is calcium acetate.)

 

[njac]

I always thought HD does NOT remove phos unlike CVVH which does remove phos.
Can somebody comment on that?

My understanding was that because the vast vast majority of phos is intracellular, you don't see a significant removal on labs with HD because you will have extra cellular movement.

Versus with CRRT, because you're not stopping it, you don't measure this same equilibrium, and it's a more consistent removal and extra cellular flow.

My severely hypophosphatemic lady definitely had a total body deficiency, she was another with a multitude of issues, medical and surgical.

 

[VCU07]

I already have 60mmoles of phos in the tpn....no nacl or kcl. I also bolused her with another 45mmole. She's had a total of 105mmoles daily for the past two days (210mmoles total). I've never given a pt this much phos for the level to go down even further! I may be taking njacs advice and see if we can add fleets to dialysate.

 

[Eugenia]

NJAC, thank you for clarification.

At our institution we never add phos to dialysate bath.
I have never seen kphos/naphos given as a bolus either
We are only allowed to dispense 15-30 mmol/250 NS IV run over 4-6 hrs as per hospital policy.

 

[njac]

It's incredibly rare for a patient with renal dysfunction to be hypophosphatemic, we're usually fighting the other direction.

The phosphosoda in dialysis bath was an out of the box suggestion (can't remember whose idea it was in the end) that ended up working.

You are correct that phos isn't "bolused" per se, the administration that you described is the usual manner that supplementation is given. Even with NaPhos, it is usually given ~30mmol/6hr. I think the "bolus" term was used to describe a one time supplemental dose, vs existing phos running continuously via TPN.

 

[VCU07]

Yes, the word bolus in this case was meant to denote an exogenous source outside the tpn. In terms of the phos, it recovered to 2.2 the next day. New challenges now exist as the pt is being switched to HD. Thanks guys

 

[KidPharmD]

Just as a note. (Glad you found a solution) In my expierence with TPN and CRRT of any kind, if the CRRT is having a profound effect on an electrolyte, the effect is usually too great to be controlled with TPN. We always give supplement outside the TPN or adjust the Dialysate/Replacement fluid.

 

[Dred Pirate]

Just as a note. (Glad you found a solution) In my expierence with TPN and CRRT of any kind, if the CRRT is having a profound effect on an electrolyte, the effect is usually too great to be controlled with TPN. We always give supplement outside the TPN or adjust the Dialysate/Replacement fluid.

same here, usually the crrt fluid is best to control electrolytes.

If you have issues with Na or K, does your institution use glycophos?