Replacement Fluids and Blood draw.

[Cryannurse]

I am a IV Nurse at one of the VA Hospital in MN. My other nurses and I were trying to figure out something about blood draw and replacement fluid like K+ and Mag. Most of the floor nurses believe that it is one hour after the fluids have been replaced, but we can't find any research to back this up. Does any one have a policy or any information about when to draw blood after electrolyte replacement.

[iluvivt, BSN, RN]

This is what I know about potassium...I will have to look into the Mag info. I am assuming you do not have a KCL protocol and are following each MDs orders. A serum K+ of 3-4mEq/L correlates with a 100-200 mEq loss. Post infusion of K. K+ levels can be expected to increase 0.25 mEq/L for each 20 mEq dose. Serum K+ levels should be drawn no sooner than one hour after administration and preferably more than one hour after the administation. It takes more than one hour for peak effect. Most protocols that I have seen are anywhere from 1-2 hours post infusion. I will see if I can find some specific info on mag draw post infusion.