Please explain this concept to me!

[TnRN43]

I am a new grad in orientation and I am confused. I have run across an issue with IVPB running too fast and it was explained to me that if the primary is set faster than the IVPB then the pump will revert to the primary rate? Or gravity takes over and will pull the fluid from the IVPB faster? I am totally lost and can't find this information anywhere (was told that I should have learned this in school, but never heard of it). I really didn't understand the explanation and didn't want to keep on asking and looking even dumber. Does anyone have a clue what I am talking about and can explain this to me?

Ok. I just had a thought. I absolutely set the IV up wrong, I know this. I'm just trying to understand HOW I got the results that I got. I set up A as primary @ 100ml. B as secondary @5ml (was to run over 20 hrs) . What happened is B ran over about 20 minutes and A didn't change at all. I SHOULD have run B as primary and A as secondary (run over 30 minutes) or just run B on it's own line. But, how did B infuse over 20 minutes?

[pandabear2185]

Sounds like an error somewhere to me! But I think what they are getting at is this. For example you primary is running NS at 250/hr. the you hang a ivpb to run at 50cc/hr. When the ivpb is done, the primary kicks in. All the meds left in that line will now run at 5x the rate it should be,until it clears. Most stuff that must run slow I used the concurrent setting and then do a flush of 5-10 cc at the same rate to clear the line. Great for drugs like lasix gtt that run at 1cc/hr. run a tko with a lasix chaser on the b-port(hospira).

[MunoRN, RN]

I'm going to politely disagree here - our Hospira pumps have a cassette system, the bags are hung at exactly the same height, and the pump knows exactly which bag to run at which time (it apparently 'knows' primary from secondary). I hate them, but they avoid this problem as long as they're set correctly.

I wonder if, like the other person who posted this, the OP set it for :20 and not 20:00 (I've come close to doing that myself in my day - you think you hit enough zeros and they didn't take). That's why I always stop and wait for the thing to start infusing so I can see how fast it's really going.

The hospira pumps use a 2 channel cassette with a dual pump, which is really just 2 pumps in one with a pump-controlled 3-way valve, this is essentially 2 primaries that can be controlled separately, not a primary/secondary set-up.

[morte, LPN, LVN]

OP,-what_kind_of_pump

[PRNketamine]

I'm not really sure this is the issue here. I don't understand the op's preceptors comment about what went wrong.

Maybe the med to run over 20hrs should have been set as primary, and the other infusion over 30min as secondary. My thought here is that way the item infusing longer is physically the primary line, while the short infusion can be Y sited in and taken down.

[carolinapooh, BSN, RN]

The hospira pumps use a 2 channel cassette with a dual pump, which is really just 2 pumps in one with a pump-controlled 3-way valve, this is essentially 2 primaries that can be controlled separately, not a primary/secondary set-up.

All I know is, the machine calls it a secondary (line B), and can run it piggyback or concurrent - I'm not technical. :) What I do know is, I hate them with a passion and miss the Alaris pumps we had when I was a civilian. We only have singles on our floor and with transplant patients its dangerous as hell with all those pumps hanging off one, and sometimes two, poles. Ridiculous. If they weren't a falls risk, they damn sure are now. I miss four channels and one brain. :)

[nurseprnRN, BSN, RN]

I think there is a difference between a single pump and one that has multiple pumps in the same box, each capable of independent thought and action. It also makes a difference whether it's an actual volumetric pump (no drip counter), or is just a flow regulator that counts drops to make its calculations as to how much fluid is going down the line. These are very different functions, which is why everybody needs to know not just how to set controls but what the box is using for brains to make its decisions.

If there is just one flow controller and there are two bags hanging above it running into the one line that enters the box, they will both have back-check valves so the one bag can't flow up the tubing into the other. However, physics being what it is, the bag that is hanging higher will have a higher pressure, so it will preferentially flow before the one hanging lower, regardless of relative size. Height is what matters in a gravity feed. So if your piggyback is higher, it will run first, and then, and only then, will the main bag resume flow.

If you have a single pump chamber with both bags running into a single intake line, the same thing will happen, because the pump draws from the fluids above it, and the higher-hanging bag will preferentially run first.

If you tell the controller/pump to run at 20cc/hr x 5 hours and then resume a maintenance rate (say, 125cc/hr) with the assumption that the 100cc piggyback (hanging higher) will then be all gone and the regular one can resume, you're messed up because in this case the main bag won't run while the piggyback, up higher, runs, and the pt will not get all his prescribed fluids.

If you have two flow controllers running in parallel, one for each line, it won't matter; you can set them independently. Same if there are two pumps. Or one of each so long as the IV lines merge below the pumps, not above one pump. They are then hydrodynamically independent actors.

I hope this helps. Try drawing pictures to figure this one out.