question about IV pump

[newohiorn]

I'm pretty sure I know the answer to this but since I really irritated my preceptor by arguing with her about this yesterday I want to be sure. I just transferred to a critical care unit so I'm in orientation but I've been a nurse for about a year and a half so I think I have a decent understanding of IV pumps.

My patient had 0.9 NS running as a maintenance IV on a pump. There was a piggyback of 3% normal saline (500 ml bag) that was to have run for 3 hours at a low rate prior to the start of my shift. When my preceptor and I went to check the patient the pump screen showed that the primary was running at 50 ml/hr but the piggyback rollerclamp was still open (with at least 300 ml left in the bag) and the piggyback bag was still raised higher than the primary bag. I pointed it out because I believe the pump was still pumping in the piggyback fluid (now at the primary rate) because the pump is going to pull from the higher bag if all stopcocks are open regardless of whether or not the screen says primary or piggyback as the pump doesn't know which bag is primary or piggyback. The preceptor disagreed with me stating the pump would pull from the primary because that's what the screen showed and she tried to demonstrate that but the piggyback bag appeared to be the one dripping before she got mad and ripped it down. I wasn't trying to be right to be right--I needed her to see that the patient may have still been getting the 3% for longer than ordered in case it would cause him a problem. Am I correct?

[AirforceRN, RN]

I don't know if these are "new" or not but the pumps we use in Vancouver know which bag its drawing from. They do this by using an electronic "eye" type device that clips on to the drip chamber of the primary bag. If the piggyback is supposed to be running and the eye senses drips from the primary the pump switches to tkvo and alarms. Similarily, if the primary is supposed to be running and the eye senses no drips the alarm sounds. Its a pretty good system and works well but can be defeated by filling the primary chamber up all the way so the eye cannot sense any drips.

[RNNPICU, BSN, RN]

In my hospital our, and am in PICU, we can program our pumps to run the secondary line. The flush fluid needs to be hanged lower than the secondary infusion, in this case the 3%. I usually program a flush of the primary fluid, just to ensure the pt gets the total dose, and I program it at a different rate just so there is no confusion as to which is infusing. Also, our pumps will have secondary scrolling across and then wil make a series of a few beeps to let you know it finished. I also stay and watch to make sure the right IV fluid is infusing (primary vs secondary)

[Christie RN2006]

I see 3% NaCl used mostly in closed head injury pt's to reduce cerebral edema. I didn't see that mentioned in the link.

We occasionally use it for our closed head injury patients too, but the majority of the time we use mannitol.