IV questions

[Marythenurse1994]

hi nurses! these questions have been going over in my mind and i've searched for answers everywhere but with fail! answering some of these questions would cure my curiosity, ladies and gents!

1) why does the primary line back up into the secondary bag if it's hung lower? i've seen that happen a few times

2) why does the primary line compete with the secondary line towards the end? i have to clamp the primary line to let the secondary line run through, but just curious?

3) when it's the last 5 mls-7mls or so of medication, i prevent them from entering the port at the primary line to prevent bubbles, clamp, run the primary line. is this advisable? does anyone else do this?

4) i've been struggling with this one. how much flush do you guys to know to give from the primary line towards the end of the infusion? do you determine this based on how much drug is left in the secondary line or just follow protocol and give the usual 25-30ml of NS?

[Mossback]

It sounds like most of the issues you describe are occurring because the secondary bag isn't high enough relative to the primary bag. Bear in mind that the top of the fluid in the primary bag must be below the drip chamber of the secondary bag. When the bags are arranged with the proper height differential, simple physics prevents the fluid in the primary from backing up into the secondary. Judging from what I see in the clinical setting, this is a pretty common issue, even among experienced nurses.

As far as flush volume is concerned, typical primary IV tubing requires 15 to 30 mL to fully flush the circuit.

Good luck with future infusions

[NICU Guy, BSN, RN]

8 hours ago, Marythenurse1994 said:

hi nurses! these questions have been going over in my mind and i've searched for answers everywhere but with fail! answering some of these questions would cure my curiosity, ladies and gents!

1) why does the primary line back up into the secondary bag if it's hung lower? i've seen that happen a few times

2) why does the primary line compete with the secondary line towards the end? i have to clamp the primary line to let the secondary line run through, but just curious?

3) when it's the last 5 mls-7mls or so of medication, i prevent them from entering the port at the primary line to prevent bubbles, clamp, run the primary line. is this advisable? does anyone else do this?

4) i've been struggling with this one. how much flush do you guys to know to give from the primary line towards the end of the infusion? do you determine this based on how much drug is left in the secondary line or just follow protocol and give the usual 25-30ml of NS?

Pascal's law is a principle in fluid mechanics that states that a pressure change at any point in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere. In other words, fluids seek equilibrium. The secondary bag should be hung so that the bottom of the secondary bag is higher than the top of the fluid in the primary bag (if you are not using a pump).

[Marythenurse1994]

@Mossback @nicuguy thanks guys! ?