Fully running IV Piggyback meds?

[HelloThere247]

Hello, everyone. Question — how do you guys get IV piggyback meds to fully run in? I will often come back to a ‘complete’ infusion but like a third or, on rare occasion, even what looks like half of the contents of the piggyback still present in the bag. I hang the fluids that a med is piggybacking on the hook included in our secondary line sets (at full length) and our Alaris pumps are preprogrammed with most of our medication rates and volumes. It’s bizarre. This never used to be an issue - the meds used to run fully and have a little overfill left to keep lines from running dry - but lately, they aren’t. I haven’t changed anything and our primary and secondary lines, pumps, meds, and fluids are the exact same as always.. I would literally rather be running the line dry than continuously having medication be not fully administered, but I don’t think I could run it dry even if I tried because my piggybacks won’t fully go in. When the pumps swap to KVO or maintenance fluids, in theory, the piggyback should still be running if it’s not dry because of gravity and they still don’t. Most of my concern about this is regarding patients not getting their full dose of meds (often antibiotics) in a timely manner, but it’s also frustrating to think an infusion will be complete and coming in to half a bag.  Does anyone have any tips? I was considering starting to vent all of my piggybacks to see if that helped at all until I realized our regular secondary lines don’t have vents. I’m at a loss for what else I could try. I can’t imagine that it’s just more overfill either unless we’re really out here overfilling things like Piper/Tazo (Zosyn) 3.375g/50mL with a solid 20-30 mL of overfill. Could be, but I doubt it. 
 

TIA.

[heron, ASN, RN]

Backflow from main line?

[MunoRN, RN]

In my experience a partially infused secondary bag occurs because the hook used to hang the primary bag was folded in half (to be about 6-8 inches long).  

The basic premise of a primary/secondary infusion is that you are creating a single fluid column, so if the top of your primary bag is in the general vicinity of the bottom of the secondary bag, then the secondary will not completely empty due to the similar height of the two bags combined with the small amount of resistance that occurs in the tubing.

[marienm, RN, CCRN]

We use Alaris pumps too.  Occasionally I've had a problem where I've screwed the secondary set onto the primary line and backprimed it (so it seems patent), but it must not be fully threaded because the secondary med will only partly infuse.  If I watch the drip chambers, I can see the primary line dripping even though it's below the secondary--so there's obviously too much resistance on the secondary line and the fluid flows more easily from the primary.  I'll see, say, 1 drip from the secondary and then 2 from the primary.  Clamping the secondary line, unscrewing the luer lock connector, and fully re-tightening it usually fixes the issue.  When I do it I can usually feel/see that the tip goes into the connector a little deeper than it did the first time.  Once I've done it, though, I don't need to do it again on that med set-up.  So if you try that and the same med set-up still doesn't infuse bags fully, then...???

Our secondary tubing does have a vent, since we do infuse some secondaries in glass bottles (mostly tylenol).  But once the fiber in the vent gets wet, it's pretty useless and I'll add a secondary vent to the membrane of the bottle with a small (25ga) needle (single use, of course, but I'm sure this is not approved practice!)  I've never had this problem with bagged meds like Zosyn, though, and I wouldn't suggest putting a needle into the top of the bag. 

Oh, one other (probably far-fetched) thought:  Are you sure your tubings haven't changed?  Our hospital is getting a lot of different products these days due to supply issues.  If the tubing you're using for secondaries is different, maybe it has too much resistance?  We have a couple of meds that run as secondaries with a filter built into their tubing.  It creates too much resistance and the fluid will preferentially drain from the primary bag.  We use a padded clamp to clamp off the primary line during the infusion and unclamp it to allow the primary to flush the line at the end of the infusion. 

Hope you figure it out (and let us know!)