There are several scenarios... Sometimes K+ is already mixed in the parenteral solution like in the 20 minute example I give you in the videos and you see the bag with red writing on top indicating that it is already in the bag.
At other times, you have "Concurrent" infusion where you parenteral fluid and IV piggy bag going at the same time. Some of the pumps you can set up with concurrent infusion so you can administer the K at a faster rate otherwise it is irritating to the vessels.
Or you can do what you used to do, backflow and mix some NS into the bag of K... and then still give it slow... because even if you backflow, cause there is only so much reserve space, the amount may still not be significant to give it at a faster rate.
In the 20 min checks... I was just talking about all the variations you might see. If it mixed in the parentral IV 1000 mL bag, then mention it in the Parenteral Fluids box. If it is a separate bag and flowing concurrently or by itself, since it has therapeutic value to it, I would write that under IV medications.