Final answer:
To prepare the 250 mL bag of normal saline with an ordered concentration of 25,000 units, the RN will need to add 625 mL of heparin.
Step-by-step explanation:
To calculate the amount of heparin that the RN needs to add to the 250 mL bag of normal saline (NS), we can use the equation:
(Heparin Concentration) x (Heparin Volume) = (Ordered Concentration) x (NS Volume)
Let's plug in the given values: 10,000 units/mL x (Heparin Volume) = 25,000 units/250 mL
Now, we can solve for the Heparin Volume:
Heparin Volume = (25,000 units x 250 mL) / 10,000 units/mL = 625 mL